Radiation induced deficets: permanent or temporary?

connsteele said:

how long on the decadron?
Is your sister done with radiation? If so, how long ago and is she still on the decadron? Also, for some reason, the docs here haven't mentioned the Avastin. His tumors are aggressive and this is his second time having radiation for a brain tumor. He was previously diagnosed with a medulloblastoma at the age of 8, which the docs say the radiation back then probably caused the GBM 26 years later as the tumors are all located in the same location where he received the boost for the medullo. Because of that, docs don't want to give him the normal dose for GBM as it would cause severe necrosis to brain tissue that has been previously affected by radiation. He's getting 2/3 the normal dose and just to the cerebellum, where the tumors are located.

The high dose Decadron helped his symptoms some, but nothing dramatic. He'd like to get off the Decadron ASAP as it affects his blood sugars (he's also diabetic).

We are thinking that he will need to apply for social security disability as we don't really know the outcome. The only thing we've been told is that these tumors won't go away and that treatment will only "slow things down." But then, when he was 8, he was given a 20 % chance of surviving 10 years and he's now 34, has lived independently, and held down a good job. So, what do the docs know!

Rory1987 said:

yeah right?!
yeah right?! That's what doctors do give survival rates and stuff to scare their patients. I don't think that treatments will only slow things down as I have read a lot of survivor stories of GBM patients who are alive 10-20 years since they were diagnosed. Blessing to your son.

Rory

palmyrafan said:

CT Scans, MRI's and Statistics
Hey again,

For the CT Scans and MRI's, my docs have always offered to sedate me (twilight sleep) in order to get MRI's or CT scans if I am having problems with vertigo or seizures. I have never needed it, but it is nice to know it is available if needed.

As for statistics, I think that is the worst thing a doctor can do is to tell a patient how long they have to live. It becomes a self-fulfilling prophecy and can keep the patient from seeking therapy and/or other medical opinions when needed.

Good luck.

Teresa

gdpawel said:

Treating Radiation Necrosis of the Brain with Avastin
When brain tumors are treated with radiation therapy, there is always a risk of radiation-induced necrosis of healthy brain tissue. Insidious and potentially fatal, radiation necrosis of the brain may develop months or even years after irradiation.

This poorly understood side effect can occur even when the most stringent measures are taken to avoid exposing healthy tissue to harmful levels of radiation. In most cases, radiation necrosis of the brain occurs at random, without known genetic or other predisposing risk factors. The only treatment options typically available for radiation necrosis of the brain are surgery to remove dead tissue and use of the steroid dexamethasone to provide limited symptom control. But clinicians have not found a way to stop the progression of necrosis, despite having tested a range of therapies including anticoagulants, hyperbaric oxygen, and high-dose anti-inflammatory regimens.

However, recent studies at M. D. Anderson have shown that the monoclonal antibody bevacizumab (Avastin) may be able to stop radiation necrosis of the brain and allow some of the damage to be reversed. Victor A. Levin, M.D., a professor in the Department of Neuro-Oncology and the senior researcher on the studies, said the findings suggest that radiation necrosis of the brain can be successfully managed-and perhaps even prevented-with bevacizumab or similar drugs.

The need for such a breakthrough is as old as radiation therapy for cancers in the brain. "No matter what we do or how good we do it, we know a small percentage of patients who receive radiation therapy to the central nervous system will suffer late-occurring radiation necrosis," Dr. Levin said. "We used to think it was the dose that was causing problems. Then we did a study and found that there was little to no relation to radiation dose or radiation volume-the necrosis occurred simply by chance. So it is impossible to say which patients will develop this problem; we just have to monitor them and hope for the best."

Like necrosis, the discovery that bevacizumab has an effect on necrosis can also be attributed to chance. Bevacizumab, a newer drug that prevents blood vessel growth in tumors by blocking vascular endothelial growth factor (VEGF), was originally approved in the United States for the treatment of metastatic colon cancer and non-small cell lung cancer. An M. D. Anderson group that included Dr. Levin decided to test the drug in patients who had VEGF-expressing brain tumors. "Some of these patients also had necrosis from prior radiation therapy, and we were struck by the positive response of those patients to bevacizumab," Dr. Levin said. "We had never seen such a regression of necrotic lesions with any other drug like we did in those patients." The observation prompted the researchers to design a placebo-controlled, double-blind, phase II trial sponsored by the U.S. Cancer Therapy Evaluation Program in which bevacizumab would be tested specifically for the treatment of radiation necrosis of the brain.

The trial is small, having accrued 13 of a planned 16 patients, and is limited to those with progressive symptoms, lower-grade primary brain tumors, and head and neck cancers. But the results have been unlike anything the researchers have seen before in radiation necrosis therapy. All of the patients receiving bevacizumab responded almost immediately to treatment, with regression of necrotic lesions evident on magnetic resonance images, while none of the patients receiving the placebo showed a response. The results were striking, and all of the patients who switched from placebo showed a response to bevacizumab as well. So far, responses have persisted over 6 months even after the end of bevacizumab treatment.

Side effects seen in the trial so far included venous thromboembolism in one patient, small vessel thrombosis in two patients, and a large venous sinus thrombosis in one patient. Dr. Levin is unsure whether the side effects were caused by therapy or the radiation necrosis itself. "We're also not absolutely sure what is causing the positive effects against the radiation necrosis," he said. "We presume it's related to the release of cytokines like VEGF, since bevacizumab is very specific and only reduces VEGF levels. We think aberrant production of VEGF is involved with radiation necrosis of the brain, and the fact that even short treatment with bevacizumab seems to turn off the cycle of radiation damage further confirms the central role of VEGF in the process."

The multidisciplinary research team has also postulated that radiation therapy damages astrocytes, a cell type involved in various brain functions, and causes them to leak VEGF. This leaked VEGF might then cause further damage to brain cells and further leakage of VEGF. "It gets to be a very vicious cycle," Dr. Levin said. "The question is, is that all that's going on?"

Dr. Levin hopes that the answers to that question and others may lead to preventive measures against radiation necrosis, beyond what is already done to control the development of radiation itself. Perhaps bevacizumab can be given in low doses before radiation or intermittently afterward to reduce VEGF levels and protect the brain from abnormally high levels of the protein. He hopes such approaches can be tested in future studies. "Just the fact that bevacizumab works has helped us understand so much more about what happens in radiation necrosis," he said. "Everything we've tried up until now has been a brick wall."

Source: OncoLog, May 2009, Vol. 54, No. 5

http://www2.mdanderson.org/depts/oncolog/articles/09/5-may/5-09-2.html

Visualizing the effects of Avastin (bevacizumab)

http://www2.mdanderson.org/depts/oncolog/articles/09/5-may/pop.html