ANA Discussion Forum
Archive => Archives => Topic started by: Mark on September 24, 2005, 06:32:37 pm
-
Earlier this week their was a post on the board where the statement was made that radiation was effective on malignant tumors , but not benign tumors such as an Acoustic Neuroma. Given the numerous studies indicating tumor control percentages in the upper nineties this is an interesting claim to make. I posed the question on the doctor's message board on the CPSG site and got the following response which I wanted to pass along to clarify the issue.
My Post
Dear doctors,
the following was recently posted on the ANA message board and seems to be an ongoing perception that radiosurgery is not as effective on benign tumors due to the slower cell replication. Control rates for AN's treated by CK or GK would suggest otherwise, but I was hoping someone could provide a "biological" explanation to support the efficacy on benign tumors.
Quote from AN board
Also AN's do not respond as well to radiation as cancerous tumors which was a factor in my decision.
Thanks Mark
Reply from Dr. Medberry
Both benign tumors and malignant tumors respond to radiosurgery. When you are treating with standard fractionated radiation, cell populations that are dividing more often will move more cells into the vulnerable part of the cell cycle between fractions. This effect, of moderate importance in standard fractionation, becomes much less important in radiosurgery, and totally important when you use single fraction radiosurgery. The bottom line is that radiosurgery is extremely effective for AN's. One big mistake that I see people making is that they carefully and intelligently investigate their condition and treatment options, then make poor decisions because their understanding is imperfect.
Clinton A. Medbery, III, M.D.
St. Anthony Hospital Cyberknife Center
(405) 272-7311
buddy@swrads.org or cmedbery@coxinet.net
I would also add that this issue is also a central arguement against radiosurgery on the House Ear web site which was debated on the board earlier this week. While I think the Doctors at HEI are great ( probably among the best) practioners of surgery of AN's, I would not confuse them as great researchers of other treatment options who have an unbiased opinion. In my opinion, I would rely on doctors at a top teaching medical center in neurosurgery ( Pitt, Stanford , Hopkins, UCSF, etc) for understanding all the options. All of them have both capabilities which certainly would suggest they are both seen as viable.
Mark
-
I am getting very confused on this issue of radiotherapy for AN's. There seems to be a lot of information and unfortunately conflicting info at that.
I had mine operated on 3 years ago and it has now returned. Options are to either sacrifice my hearing totally or have radiotherapy treatment. I live in Sydney and have seen the "local" top specialist in this field and he was quoting statistics of successful Linac treatment of around 98%. With very few cases of facial dissorders over a 16 year period. However, there is about a 1 in 50,000 chance that the radiotherapy treatment can turn the benign AN into a malignant tumor. Odds are high but still a worry.
I would love to see a formal study done if anyone has one.
Larry
-
http://www.moffitt.usf.edu/pubs/ccj/v5n2/article5.html (this is a related article. when I did my research I often looked outside the box of AN and looked at treatment options for brain tumors.
I still have not been able to find the information that I had seen.
What I had read was that since the AN and the nerve are made of the same cells they are equally susceptible to radiation and thus both can be damaged. Where as cancerous cells were often more radiosensitive than the surrounding cells and this often improved the efficacy of the treatment.
If radiation can damage an AN it can damage your facial nerve.
-
However, there is about a 1 in 50,000 chance that the radiotherapy treatment can turn the benign AN into a malignant tumor. Odds are high but still a worry.
This post is a classic example of the emotive fears of radiation. I guess maybe we've all lived in fear of nuclear war in these times and the very word radiation can be frightening. However, radiation has been used in medicine long before it was used as a weapon, it's a very powerful thing, but it can help as well as hurt. Let's all look closely at the statement above. Larry is trying to make a decision between another surgery and radiosurgery, and is worried about a 1 in 50,000 chance of malignant transformation. Why isn't he alot more worried about the 1 in 100 chance of immediate death on the operating table? In the extremely unlikely event of malignant transformation, there is still the possibility of surviving the malignancy, whereas there is no chance of surviving when you die on the table. Also, there is no evidence that radiosurgery even caused the malignant transformation in the very few cases that have occured, because just about an equal small number of malignant transformations have occured following surgery, with no radiation whatsoever. Some doctors believe there is actually no such thing as malignant "transformation" in schwannomas, but that they had a malignant element the whole time. In schwannomas, very rarely they can have small pockets of malignant cells that can be missed when biopsied, so it's hard to say surgery or radiation caused it to become malignant, when it may have been malignant the whole time.
I would love to see a formal study done if anyone has one.
There have been so few cases, that would be difficult. But here's the closest thing I could find for you:
http://www.anarchive.org/malignancy.htm
http://www.moffitt.usf.edu/pubs/ccj/v5n2/article5.html (this is a related article. when I did my research I often looked outside the box of AN and looked at treatment options for brain tumors.
The only info that source provides on radiosurgery is this:
High-intensity, focused radiotherapy (gamma knife or linear accelerator radiosurgery) is effective in reducing the growth rate of benign or intermediate malignant tumors.
The experience of radiation therapy, especially radiosurgery, has increased dramatically during the last decade, and the success rate of tumor control is high. In initial reports of radiosurgery on vestibular schwannomas, complications included cranial neuropathy consisting of 30% delayed facial paresis, 50% hearing loss, and 33% trigeminal neuropathy.25 Recently, the result has been revised with better outcomes achieved with a new dosimetry plan. However, it is not clear if a lower dose will result in the same rate of tumor control. Additionally, patients who have recurrent tumors after radiosurgery experience worse outcomes with microsurgery.10
The last part is disputed in the neurosurgeon community, but even if true, I'd take a 2-3% chance of a more difficult surgery, with the 97% chance to avoid surgery any day. But that's a personal choice that must be made.
The rest of the info pertains to radiotherapy, which is not stereotactic and radiates healthy tissue as well. And even with radiotherapy, your source still gives a control rate of 97%, and cites the complication rate as minimal. Maybe you understood conventional fractionated radiotherapy to be the same as FSR, but it is different. If that's the case, Dr. Medberry's comment about imperfect understanding rings true.
What I had read was that since the AN and the nerve are made of the same cells they are equally susceptible to radiation and thus both can be damaged. Where as cancerous cells were often more radiosensitive than the surrounding cells and this often improved the efficacy of the treatment.
If radiation can damage an AN it can damage your facial nerve.
Actually, the AN is made of the same cells as the nerve sheath, not the nerve itself. Schwann cells are the cells that surround the nerve. Nerve cells are called neurons. Nerve cells have a much better ability to recover than schwann cells, and that ability is thought to be even more when using hypofractionated radiosurgery, radiosurgery done over 3-5 sessions, not to be confused with conventional fractionated radiotherapy. And again, it doesn't work better on cancer cells, just faster, and mostly only on cancer cells that are metastatic, not primary brain cancer. If it were the case that radiation was more efficient on cancer cells, the GBM would be cured in days.
-
Radiation vs.Surgery
Same arguementative junk. Same issues and biases from pts. and Drs. alike. All report stats in their favor. One criticizes another Tx provider as per MedBerry. HEI has treated more pts. successfully over the years than any, whether surgically or with radiation. They did once employ GK.
'I'm very thankful anyone is helped by the Tx type utilized'.
Either choice involves risk and no guarantees. Some risks are more immediately obvious.
Geesh. Anything worthwhile or new to offer?
Russ
-
Radiation vs.Surgery
 Same arguementative junk. Same issues and biases from pts. and Drs. alike. All report stats in their favor. One criticizes another Tx provider as per MedBerry.
It's not an arguement, it's a discussion and an attempt to assist newly diagnosed patients in obtaining correct information to base their decisions upon.
HEI has treated more pts. successfully over the years than any, whether surgically or with radiation.
They did once employ GK.
House has not employed gamma knife to my knowledge. They treat about 200 patients a year surgically. They certainly don't treat more patients with radiation than other facilities.ÂÂ
From their own website:
With improvements in the results of surgical therapy for acoustic neuroma, radiation therapy is infrequently used by House Clinic in the treatment of acoustic neuroma.
http://www.houseearclinic.com/acousticneuroma.htm
Again, radiation therapy is not radiosurgery.
'I'm very thankful anyone is helped by the Tx type utilized'.
Either choice involves risk and no guarantees. Some risks are more immediately obvious.
Very true, but patients need to have a clear understanding of both options.ÂÂ
Geesh. Anything worthwhile or new to offer?
This is the radiaton/radiosurgery forum, so you should probably expect discussion about that topic. Do you have anything worthwhile to offer? First you said gamma knife was created to treat cancer when it was not, now you say House has treated more patients succesfully with radiation than any other facility when they don't regularly use radiation. Where are you getting this info? Please provide any sources you may have. I don't see any radiosurgery patients posting false info in the microsurgery forum, why do we not deserve the same consideration?
-
There seems to be alot of confusion, and interchanging of treatment outcomes and risks, between stereotactic radiosurgery/FSR, and radiation therapy. The former involves precise targeting with higher doses over a short period of time (1-5 days), and minimal exposure to surrounding tissue, the latter involves much lower doses applied to the whole brain over a much longer period of time (>20 days). Radiation therapy has not been used frequently for AN's since radiosurgery has emerged, and is more suitable for brain cancers, because unlike AN's, brain cancer cells are often found throughout the brain so it's necessary to irradiate the whole thing. The risks and outcomes are quite different, and the belief that radiosurgery can cause new malignant tumors to develop comes from data involving whole brain radiation therapy in which all the healthy tissue in the brain is affected. These two procedures should not be confused.
-
as I said that was only a related article not the information I had at the beginning of the year. I do not know if I will ever find the information I had that helped me to make my decision.
And I was aware of we were taking nerve sheath I should have been more precise.
And posting the article was not in anyway supposed to be anti radiation. I am not trying to prove or disprove anything I already have my outcome. God willing soon all of this will only be a memory. :)
-
as I said that was only a related article not the information I had at the beginning of the year. I do not know if I will ever find the information I had that helped me to make my decision.
I see. I was able to find an article about radiation effects on cancer cells:
Indications for Radiation Therapy
Radiation therapy is the principal treatment for various skin cancers; cancers of the mouth, nasal cavity, pharynx and larynx; brain tumours and many gynaecological, lung cancers, and prostate cancers.
Radiation therapy plays a leading role in conjunction with surgery and/or chemotherapy in breast cancer, bowel cancer, bladder cancer, Hodgkin's disease, leukemia and lymphomas, thyroid cancer, childhood cancers, gynaecological and testis tumours, as well as many other cancers and certain benign conditions.
Action of Radiation Therapy
Radiation therapy works by destroying cells, either directly or by interfering with cell reproduction using high-energy X-rays, electron beams or radioactive isotopes. When a radiated cell attempts to divide and reproduce itself, it fails to do so and dies in the attempt.
Normal cells are able to repair the effects of radiation better than are malignant and other abnormal cells. Thus, normal cells are able to recover from exposure to radiation and maintain integrity and viability better than malignant cells.
http://www.healthcastle.com/radiation.shtml
And I was aware of we were taking nerve sheath I should have been more precise.
Quite alright. :) Another point about nerve cells and schwann cells is that nerve cells are meant to conduct electricity in the form of the impulses which send signals to and from the brain, so they should be much more able to recover from the electromagnetic energy applied during radiosurgery. The abnormal schwann cells are not conductors of electricity and should be more vulnerable to the radiation.
God willing soon all of this will only be a memory. :)
I certainly hope so. :)
-
I am currently scheduled for surgery at HEI, but am now reconsidering in light of many folks suggesting I look at radiosurgery instead. My AN is small (I don't know the actual size), but I have no side effects other then Tinitus. It's just a freak accident it was found. I was initially discouraged from radiation due to a vast history of cancer in my family. In reading further and from encouragement from many on this site, I am now considering radiosurgery.
I am confused my the variety of terms...radiosurgery (I assume this is the "parent" term referring to all types of radiation for tumors), gammaknife, cyberknife and the general term radiation therapy. Can anyone shed some light of differences?
What are the side effects and/or risks of radiosurgery?
I am in a profession in which I need to retain my hearing and which requires complete functionality of my facial muscles. It has made the whole idea of surgery most distressing to me. I have a 5-6% loss of hearing which is approximately 30db.
I live in Atlanta, and I don't see Cyberknife being offered here - suggestions on where I might consider? I know Stanford is listed, I would be interested in other recommendations as well.
Thanks! :)
-
I am confused my the variety of terms...radiosurgery (I assume this is the "parent" term referring to all types of radiation for tumors), gammaknife, cyberknife and the general term radiation therapy. Can anyone shed some light of differences?
Glad to see you're weighing all options! Radiosurgery is a term applied to focused beams of ionizing radiation (gamma, x-ray, proton, etc.), which all precisely intersect at the target tissue, and delivers very little radiaton to surrounding healthy tissue. It achieves surgical accuracy, hence the name. It's quite different from whole brain radiation applied to cancer patients, like the difference between a shotgun and a sniper rifle. All forms of ionizing radiation achieve the same effect on tumor cells, it scrambles the tumor cell DNA and takes away it's ability to reproduce itself. When the cell tries to reproduce, it fails and dies. As far as the difference between CyberKnife and gamma knife, CyberKnife uses a linear accelerator which emits x-rays, and gamma knife uses cobalt that emits gamma rays as it is decaying. Again, both affect the cells the same. Both machines are comparable in accuracy (sub millimeter), although some say CyberKnife is a bit more accurate. Gamma knife is done in one treatment, because a metal frame has to be attached to the skull to keep you completely still, whereas CyberKnife is usually done in three treatments because it uses real time x-ray images of your skull to track the tumor and it even adjusts for small movements, a plastic face mask keeps you still and allows them to line up the ceiling mounted x-rays to track the tumor's location. One advantage of three treatments over one is it is said to allow healthy tissue time to recover overnight, before treatment the next day. Abnormal cells don't recover as quickly. So far the results of fractionated treatments have backed that theory up, and result in less chance of any nerve damage. ÂÂ
What are the side effects and/or risks of radiosurgery?
From IRSA webite (some of these side effects only apply to gamma knife, and the headframe it uses):
Early complications may include:
Common complications:
· local pain and swelling in the scalp
· headache
Rare complications:
· skin reddening and irritation
· nausea
· seizure
Delayed complications may include:
Uncommon complications:
· local loss of hair in superficial lesions
· local brain swelling in the treatment site
· local necrosis in the treatment site
Rare complications:
· visual loss (dependent on diagnosis)
· deafness (dependent on diagnosis)
http://irsa.org/qa.html
I am in a profession in which I need to retain my hearing and which requires complete functionality of my facial muscles. It has made the whole idea of surgery most distressing to me. I have a 5-6% loss of hearing which is approximately 30db.
Then you probably should seriously consider CyberKnife, which of all treatments offers the best chance of not sustaining any nerve damage.
I live in Atlanta, and I don't see Cyberknife being offered here - suggestions on where I might consider? I know Stanford is listed, I would be interested in other recommendations as well.
On the House thread after your exchange with Josh, I provided you with contact info for Dr. Rosenberg in MO, he practices CyberKnife and is quite a bit closer to you than Stanford. Since the machine does the work, and the CK treatment plans are fairly universal, you should achieve the same outcome at either facility. :)
-
I remembered more information about radiation effect on cancerous vs. non cancerous cells. Maybe somebody else will have luck finding sources for it.
It was due to a mechanism that fixes DNA. regular cells are able to repair the damage done to some extent whereas cancer cells are not able to repair the damage as easily. Thus benign tumors often can fix themselves while still leaving the gene for replication activated.
Sorry that's the best I've got.
-
The consistent control rates of 95% or above would not suggest these benign tumors are fixing themselves often. It's true normal cells have the ability to repair themselves, but AN cells are abnormal, and divide much more rapidly than normal cells. The main difference between benign tumors and cancer is that cancer cells can break off and spread, and are much more invasive and infiltrative, and therefore much more difficult to irradicate. The vast majority of AN's shrink dramatically when followed up long enough after radiosurgery, some even disappear alltogether. I'm still very interested to see the source of your info, I've not been able to find any studies or articles suggesting that AN cells are normal.ÂÂ
Normally, the growth and reproduction of every cell in the body are regulated; this regulation, in turn, determines the size and functions of tissues and organs. If a normal body cell begins to grow abnormally and reproduces too rapidly, a mass of abnormal cells eventually develops that is called a tumor. A tumor generally contains millions of genetically identical abnormal cells before it can be detected or felt.
If the cells of the tumor remain localized at the site of origin in the body and if they multiply relatively slowly, the tumor is said to be benign. Benign tumors, such as cysts, warts, moles, and polyps, do not spread to other parts of the body. Benign tumors usually can be removed surgically and generally are not a threat to life. In fact, benign tumors weighing several hundred pounds have been surgically removed from persons who then recovered fully. Benign tumors cannot regrow if all of the abnormal cells are removed by surgical excision of the tumor.
http://www.cancermed.com/patient_information.php?table=patient_info&page=8
Stereotactic radiosurgery works the same as all other forms of radiation treatment. It does not remove the tumor or lesion, but it distorts the DNA of the tumor cells. The cells then lose their ability to reproduce and retain fluids. The tumor reduction occurs at the rate of the normal growth rate of the specific tumor cell. In lesions such as AVMs (a tangle of blood vessels in the brain), radiosurgery causes the blood vessels to thicken and close off. The shrinking of a tumor or closing off of a vessel occurs over a period of time. For benign tumors and vessels, this will usually be 18 months to two years. For malignant tumors and metastatic tumors, results may be seen as soon as a couple of months as these cells are very fast-growing.
http://www.irsa.org/radiosurgery.html
Maybe you read that cancer cells are affected more quickly because the cells turn over faster, but the abnormal cells in a benign tumor are just as vulnerable to radiation, it just takes a bit more time.
Like Dr. Medbery stated, "The bottom line is that radiosurgery is extremely effective for AN's."
And that statement is backed up with plenty of published data.
-
Jamie,
Thanks, your innformation is very helpful, and I feel quite encouraged! :D
I have checked and found several other locations for the CyberKnife including
(1) CyberKnife Center UT Brain & Spine Institute University of Tennessee Medical Center in Knoxville, TN
(2) NCH Regional Cancer Institute, Naples, FL
(3) The CyberKnife Center of Miami, FL
(4) Georgetown University in DC
(5) Sinai Hospital of Baltimore, MD
All of these are East Coast and not too difficult for me to get to. Can anyone comment on their experience at any of these locations? Is anyone aware if Boston has a location? That's where my family lives, and it would be easy for me to have it done there too...
Thanks!
-
Dear Diss,
I too am scheduled at House for Nov. 8 w/Dr Brackmann. Ins and I are fighting.That date does not look at all possible. I had to change local neurotologist and am not really thrilled with him. I have a 1 cm AN (I hope) and will be going for another MRI Monday. I had never considered GK or CK until I started talking to Dr. Medbury. I am in the same boat with you. If I have facial paralysis and a lot of the complications of surgery I will not have a job. I am just a couple of years away from retirement and can't give it up now. Plus I raise horses and need my balance. I am terrified of surgery and when people start quoting statistics my stomach turns. They don't mean a lot to me. It is a 1:100,000 that I have AN and I also have autoimmune ear disease that happens to only 1.6% of AN people. So, given a 1 in 100% chance of dying of the surgery and a 10% chance of paralysis of the face is just not the greatest of odds. I am researching furiously on the GK and CK route. I was diag. 6 months ago and I am not a good wait and watcher. Something has all along told me surgery even with Dr. B may not be the way to go. The women in my family are long lived and I may be looking at 30 to 40 more years. Believe me if this thing has grown an appreciable amount I will go the CK route so fast it will be hard to make the appointment fast enough. I have always kept up my appearance and because of that have a nice job that I have defended against a lot of younger want to be's. I feel great and want to stay that way so if you can direct me to what ever good information you find, let me know.
-
Hey Sandy,
Glad to hear you're checking other options too! While I'm not (you couldn't pay me enough!) a doctor, you sound pretty ideal for radiosurgery - glad you're looking into it.
If you've read more than a handful of posts on this site, you know the general consensus of patients: doctors will promote the options they are most comfortable and experienced with. My own father is a surgeon, and he agrees with that statement 100%. It's human nature, but not helpful when you're looking for the best treatment option and the two main ones are so different.
I'm a surgery candidate myself, having translab for a 3cm AN in three weeks. But I was glad to have all the cards on the table, so to speak, before I made my decision. Check out this thread, and the "House Ear Institute" thread under "Microsurgical Options" if you haven't already done so - lots of info there.
Good luck, and keep us posted!
Josh
-
DB,
Since Radiosurgery in general is highly computerized the ability of each center to deliver consistently good treatment is very high. In terms of CK, I know that Miami, Sinai and Georgetown have all had the machine for at least 3-4 years so they should be very experienced.
CC, another poster recently shared some of the exchange on CK that she had with Dr. Chang at Stanford. The listing of all the responses to her questions is in her post in the radiosurgery section of this board, but to the question of expereince and human involvement in delivering treatment, Dr. Chang's response was:
"The choice of the positioning for each beam is chosen by the computer. The doctors input the tumor volume, and the computer calculates the optimal beam positions based upon the millions of possible iterations. The beam positions are not chosen by a human, but by the computer, so there is not any human input as to the choice of beam positions, and therefore nothing that gets delegated since it is all done by the computer."
Hope that helps
Mark
-
Thanks Mark!
I have been reading all the posts as well. I was thinking Miami might be a good choice, and am glad to see the information on how long they had their machines. I had read what CC had posted based upon conversation with Dr. Chang. Stanford is an option, but think I'd like to go closer...
Will keep all posted!
-
Sandy,
You're doing all the right things...like you, I was diagnosed 5 months ago, and I'm not one to let things sit. I'm also a professional, I am President of a consulting firm, and at 48, look and feel great and plan to stay that way! The folks on this site have been great and have provided not only a rich stream of information, but also great encouragement.
I have several relatives and friends also researching information. My cousin's husband has a surgeon relative that he's consulted on my behalf, and he asked why I hadn't considered CK - I have no symptoms other then Tinitus, so I'd be a great candidate. My business partners father-in-law is the head of Surgery at Emory and he's going to check with him. Everything I'm seeing, hearing and reading is leading me to CK. I will be getting more information in the next week, I'd be glad to share anything I find out with you if you're interested. At this point, I'm feeling best and most reassured about CK - as Josh pointed out to me, surgery should be my last option...I believe he is absolutely correct.
Best of luck!
-
from the national cancer institute:
What is radiation therapy?
Radiation therapy (also called radiotherapy, x-ray therapy, or irradiation) is the use of a certain type of energy (called ionizing radiation) to kill cancer cells and shrink tumors. Radiation therapy injures or destroys cells in the area being treated (the “target tissue�) by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue.
Still not the info I had but still interesting.
-
Distressed,
I had 6 mo. MRI. The AN has grown and has become cystic. I am told I need to make up my mind. No more watch and wait. Have you heard how CK is for cystic AN's? The radio oncologist here says I should be fine with CK. He has only done 10 CK around 60 GK. for AN's
My neurotologist says if it is cystic it is nothing to fool around with and why take a chance on something that is not going to get it out. Back to confusion again. Seems like every time I go to the Dr. it is something new. How is the research going?
-
from the national cancer institute:
What is radiation therapy?
Radiation therapy (also called radiotherapy, x-ray therapy, or irradiation) is the use of a certain type of energy (called ionizing radiation) to kill cancer cells and shrink tumors. Radiation therapy injures or destroys cells in the area being treated (the “target tissue�) by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue.
Still not the info I had but still interesting.
AN cells are not normal. If they were, radiosurgery would not control over 95% of them. AN cells are abnormal, just like cancer cells only they turn over more slowly, they do not invade other tissues, and they do not spread. But the cells in benign tumors are not normal, or none of us would be posting on this board, it wouldn't even exist.
Neoplasm, or tumor, tissue composed of cells that grow in an abnormal way. Normal tissue is growth-limited, i.e., cell reproduction is equal to cell death. Feedback controls limit cell division after a certain number of cells have developed, allowing for tissue repair but not expansion. Tumor cells are less responsive to these restraints and can proliferate to the point where they disrupt tissue architecture, distort the flow of nutrients, and otherwise do damage. Tumors may be benign or malignant.
http://www.encyclopedia.com/html/n1/neoplasm.asp ÂÂ
Radiation therapy works by destroying cells, either directly or by interfering with cell reproduction using high-energy X-rays, electron beams or radioactive isotopes. When a radiated cell attempts to divide and reproduce itself, it fails to do so and dies in the attempt.
Normal cells are able to repair the effects of radiation better than are malignant and other abnormal cells.
http://www.healthcastle.com/radiation.shtml
-
Distressed,
I had 6 mo. MRI. The AN has grown and has become cystic. I am told I need to make up my mind. No more watch and wait. Have you heard how CK is for cystic AN's? The radio oncologist here says I should be fine with CK. He has only done 10 CK around 60 GK. for AN's
My neurotologist says if it is cystic it is nothing to fool around with and why take a chance on something that is not going to get it out. Back to confusion again. Seems like every time I go to the Dr. it is something new. How is the research going?
Here is a series of MRI scans of a cystic AN following radiosurgery:
(http://www.ajnr.org/content/vol21/issue8/images/medium/ajnr-21-08-15-f05.gif)
FIG 5. Serial contrast-enhanced axial T1-weighted images (450/17/5) in a 64-year-old woman show enlargement of the cystic component and transient loss of contrast enhancement in the solid component at 3 months; regression of the cystic component, slight enlargement and recovery of contrast enhancement of the solid component, and slight regression of the overall tumor at 18 months; further enlargement of the solid component, no change in the cystic component, and regression of the overall tumor at 24 months; and remarkable regression of the tumor at 50 months. GKRS indicates gamma knife radiosurgery; mos., months after gamma knife radiosurgery
http://www.ajnr.org/cgi/content/figsonly/21/8/1540
-
I do like that on done at 50 months.
Sandy
-
Hi All,
I went to see Dr. Clinton Medbery today. He answers questions on the Cyberknife patient support forum. He is really nice guy. Above all extremly honest. He does not see a thing wrong with surgery. However, he thought I would do well with either cyberknife or gammaknife or surgery if I want. He does not think the tumor is necessarly cystic and said my last MRI is is not very clear and taken from a different angle and it would be hard to tell just how much it had grown. Could be the 3 mm in 6 months I was told or more or less. there is just not a way to tell how much it had grown, just that it had grown. He was not nearly as down on surgery as the neurotologists are on radiosurgery. He told me up front the down side of each treatment and how they were done. He is also very willing to listen. He kept my films to present to a panel and will get back to me with their opinion as a body. I didn't come out of his office feeling beat up as I have with other doctors.
-
Okiesandy:
Is Medbery in Oklahoma?
Jeanne
-
Yes, Dr. Medberry is at St Anthony hospital in Oklahoma city
attached is his profile
Clinton A. Medbery, III, M.D.
Medical Director
St. Anthony Hospital Cyberknife Center
Oklahoma City, Oklahoma
Email: buddy@swrads.org
Patient appointments:
Phone: (405) 272-7311
Fax: (405) 236-3888
Dr. Medbery is board certified in both medical oncology and radiation oncology. He specializes in radiosurgery of both intracranial and body cancers and benign tumors. Research interests include the use of the Cyberknife as a non-invasive and rapid treatment of prostate cancer and pancreatic cancer. He also is an expert in the radiosurgical treatment of metastatic disease in the brain, with an experience of several hundred treated cases.
-
What is the difference in CK and FSR using the Peacock method? Is one better than the other?
ITwo years ago when I was doing my investigations I remember a study performed in the UK that made a remarkable statement, that there were no completely blind, unbiased medical papers on the each of the treatment options. Has this changed? If I recall they had reviewed every paper submittted up to a certain date and ranked them using some universal system as to accuracy.
-
Ned,
I beleive the Peacock system is an IMRT system ( Intensity Modulated Radiation Therapy) whereas the CK isan active targeting SRS system. Both are Linac and both are very effective in treating Skull based tumors. Here is a one discussion of there advantages and disadvantages:
Shaped Beam Systems
The recent development of IMRT or Intensity Modulated Radiation Therapy has added another dimension to multi-fraction radiation therapy. These linac-based technologies use computer-controlled "beam-shaping" to do a better job of conforming the radiation dose to the shape of the tumor or other lesion. This form of advanced radiation therapy can be utilized at virtually any location in the body. IMRT technology enables a mechanical device (called a multi-leaf collimator) that is typically attached to most modern medical linear accelerators, to dynamically reshape the outlines and intensity of the radiation field during cancer treatment. When combined with sophisticated planning software, IMRT fits the dose of radiation to a target much better than conventional radiation therapy, and thereby minimizes the volume of surrounding normal tissue that is injured by treatment. While it appears that IMRT may produce fewer side-effects than conventional radiation therapy, IMRT is not as spatially precise as radiosurgery. Because of this imprecision, a full course of IMRT treatment is typically administered over multiple treatment sessions (typically 20-30+). Common brand names include X-Knife (Radionics) and Novalis (Brain Lab). Advantages of Shaped-Beam systems include:
1. The capacity to treat most regions of the body with IMRT
2. When coupled to an invasive stereotactic frame, precision targeting for brain tumors that approaches, but does not equal, that of the Gamma Knife or CyberKnife.
3. The capacity to more accurately target extracranial (non-brain) tumors than standard radiation therapy
4. An ability to deliver fractionated intracranial or extracranial treatment
Disadvantages of the Shaped Beam systems include:
1. The need for an invasive head frame (similar to the Gamma Knife) to assure treatment accuracy when used for brain radiosurgery (single fraction)
2. Less treatment accuracy when multiple fractions are used to treat areas of the brain where the use of an invasive head frame is impractical
3. A significantly lesser degree of targeting accuracy when treating extracranial tumors compared to brain radiosurgery
4. Treatment accuracy is degraded further when the target moves during radiation delivery from either natural breathing or patient movement
CyberKnife System
The CyberKnife System is an SRS system utilizing contemporary technology that is designed to be the most accurate and flexible tool available for aggressive therapeutic irradiation. The CyberKnife was designed to address the limitations of frame-based SRS systems and expands the application of radiosurgery to sites outside of the head. It is the only system to incorporate a miniature linear accelerator mounted on a flexible, robotic arm. An image-guidance system that can track target location during treatment also enables the CyberKnife to offer superior targeting accuracy without the need for the invasive head frame. While Gamma Knife and linac-based systems can perform radiosurgery in the brain, true radiosurgery for areas outside of the brain is difficult if not impossible to perform with these systems. For more detailed information on the CyberKnife, see CyberKnife Overview.
Advantages of the CyberKnife include:
1. No invasive head frame or other rigid immobilization device is required
2. The ability to perform radiosurgery (1-5 fractions) on targets throughout the body, not just the brain
3. Precise targeting (within 1 mm) of selected lesions in the brain and body
4. A unique ability to provide real time monitoring of the treated target throughout treatment using an advanced image-guidance system
5. A unique ability to correct during treatment for limited target motion (e.g. due to small patient movements)
6. The capacity to easily perform staged radiosurgery
Disadvantages of the CyberKnife include:
1. The need for placement of very small markers (fiducials) via a needle for the treatment of targets outside of the head
2. Compared to other radiosurgical devices, treatment takes longer when multiple tumors are ablated during the same treatment session.