Secondary Cancer from Radiation treatment

[May3]

Does anyone know about secondary cancer or malignancy caused from radiotherapy or stereotactic radiosurgery treatments?

[Mark]

In the roughly 40 years since GK was first used on an AN there have been a handful of cases reported in the medical literature. Ironically that is about the same number reported following open surgery, although for some odd reason no one seems to ask that question  . statistically, I believe the odds are around 1/100,000 or something like that.

[tony]

The sheffield Gamma knife unit had one case,
out of 3,000+ treated over 10 yrs
Even then the original tumour was showing signs,
pre treatment of unusual growth patterns
(It may not actually have been an AN after all..)
There is a knife vs radio bias behind the stories maybe ?
Best Regards
Tony

[Lorenzo]

the way it was put to me when I asked that same question was: 'about the same changes of getting cancer in any other way, and possibly less'. I know that Stanford at the time I was treated had no malignancy on record, and they had been using CK since the early 90s I think.
Lorenzo

[sgerrard]

Not sure if you want the technical data or not, but here goes:
http://www.ncbi.nlm.nih.gov/pubmed/17704364

From the abstract:
There are currently 19 reported cases of tumors linked with stereotactic radiotherapy/radiosurgery, to which we add our second institutional experience of a patient.

That is the total of all known cases to date with any form of stereotactic radiation treating any kind of benign brain tumor.

Review of these 20 cases revealed 10 de novo secondary tumors, of which eight were malignant, with six being malignant gliomas.

8 new malignant tumors found (not sure why the 2 benign ones are being counted).

The majority of the cases (14 of 20) involved AN, with most being in patients with neurofibromatosis-2 (NF2; 8 of 14), reflecting the large numbers and long-term use of radiotherapy for AN.

8 cases of NF2; 6 cases of regular AN. That's the grand total, world wide, in the entire history of radiation treatments.

The exact carcinogenic risk after radiotherapy is unknown but likely extremely low.

I agree with the conclusion.

Steve

[Tumbleweed]

Thanks for the great research, Steve.

Put another way, I've been told that the cancer risk from radiosurgery is no more than that for the general population.

Best wishes,
Tumbleweed

[FlyersFan68]

  This is a tough question for many reasons. First, Lorenzo mentioned CK being used in the 90's but I don't believe that to be accurate since CK was FDA approved in 2001. Mark stated that GK has been in use for forty years which is true but here's my discrepancy.   

   When I was seeking treatment in 2003 I was looking into GK. I desperately wanted to speak to someone that had GK 20 years ago and couldn't find one person. My guess is that the first 20-25 years of Gamma Knife use on acoustic neuromas was performed only on the elderly. Likely, the patients that had GK done in the 70's and 80's passed on due to age/health issues? This is why long term results are very important.  I don't believe we've seen the true outcome in those early patients

   I personally agree that the risks of malignancy is likely small but they are certainly elevated and to what extent we can only speculate. Nothing is risk free. This is why they use lead jackets for quick scans including the ones performed in the dental office. The rooms that host CK & GK have very thick concrete walls at around 10' thick. However, radiation is curing people everyday. To what extent the cure can only be seen over time and varies person to person but the immediate relief and convenience is good enough for many. CK is effectively treating tumors throughout the entire body. The only problem that AN people face is that acoustic neuromas are benign and patients with benign lesions are expected to live long healthy lives unlike many cancer patients. This is what makes treatment for acoustic neuroma so difficult and personal. I was 34 when I was diagnosed so I wanted immediate results with no long term fear of direct and non-direct malignancies even if the odds seem low. This was important to me. Also, In 2003 CK was barely around and even mentioned.   

   Re: Malignancy!  Think about this...how difficult would it be to prove that a malignancy found 20-30 years following radiation for an acoustic neuroma was caused directly by the radiation treatment? Possible? (of course) Although, how can one be entirely sure? This is probably why we may never know the truth. The possibility can never be erased or ruled out. Radiation is it's various forms is known to be somewhat dangerous over time. Remember, some people smoke their entire lives knowing the risk and never get cancer while others smoke for a shorter time and do get cancer.   

   Now this leaves us with the documented cases of direct malignancies (the very site and immediate surrounding area of radiation treatment). As of today, the number is closer to 20 but this number includes and favors NF2 patients. Those tumors are known to be a bit more aggressive than the ordinary sporadic AN. 
 
  Briefly, this is my perspective and personal research on the topic. 
  There were a few other reasons for me to personally elect surgery and I would be glad to discuss this further. I've mentioned earlier in a previous post that CK is off to a wonderful startand should be investigated. Some older machines had some software issues but maybe they have it all figured out now. The immediate results are usually the best results so more long-term data is definately needed. Long term data for GK is still impressive 10-15 years later but that is only out of Pittsburgh. Pittsburgh highly endorses GK and is a leader in the use of GK treatment. House has impressive and published reports regarding surgery. House also has a nice little site that addresses all these issues at   acousticneuroma.org  ....(if I remember correctly)

May3,
  There is still some mis-information out there regarding AN and treatments so the best research is your own research. Finding one of the three treatments is a very tough decision and even though surgery is initially tough to choose next to an out-patient procedure it does have advantages. For example, the relief I have knowing that it's gone is extremely comforting for me. Consequently,  it cost me my hearing on one side. IMO, most people will either lose their hearing or watch it deteriorate over time anyway. It's the nature of the beast. 

  Maybe you've already had treatment but you raised a very good question and I had to leave my input with due respect to others (my AN friends).  I hope that I have given you an accurate and unbiased perspective. My Pennsylvania friend (Mark) is always helpful should you need further CK assistance.       If you are pre-treatment feel free to contact me anytime.

[FlyersFan68]

Steve,

Thanks for that link. I've never seen that published report despite recently learning the new count. Hope all is well.

[sabuck]

One important point to consider too is a person's family history that may be predisposed to developing cancer. On my paternal side of the family, each of my father's siblings, him included, developed various cancers leading to their ultimate demise. This is the primary reason that I chose surgery over GK. Why give CA a catalyst to develop when it may not need one to begin with? At least that was my thinking.
 

[FlyersFan68]

Good Point. I remember thinking about that too. My father died from osteogenic sarcoma (spelling??).

[jb]

Quote from Dr. Kondziolka (Univ. of Pitt. Med. Ctr) in IRSA BrainTalk newsletter, 2004:
(http://www.irsa.org/publications/Vol9No2.pdf)

"...patients inquire about the risk of delayed malignant transformation. Malignant schwannomas are rare, but have been reported to occur spontaneously, after prior resection, and after irradiation. We answer that delayed malignant transformation is always a risk after irradiation, but the risk should be very low. We have not yet seen this in any of our 6400 patients during our first 17 years of experience with radiosurgery, but quote patients a risk of 1 in 1000 over the next 5–30 years of their life. We believe the risk of developing a tumor years after radiosurgery is much less than the risk of mortality immediately after a resection, and likely less than the risk of the patient developing another tumor on his own in another body location."

-Douglas Kondziolka, M.D., M.Sc., F.R.C.S.(C), F.A.C.S., is Professor of
Neurological Surgery and Radiation Oncology at the University of Pittsburgh
Medical Center Presbyterian and Co-director of the Center for Image-Guided
Neurosurgery

[Jim Scott]

They'll be some reservations over radiation treatments for AN's for some time to come.  The 'C-word' scares people to the point of irrationality, sometimes.  That is unfortunate but a fact of life. 

Frankly, by the time the really long-term studies are completed, most of us will be long gone.  Admittedly, the thought of having radiation shot into your head is just too scary for some folks, never mind the statistics.  Conversely, some people can't abide the thought of a surgeon drilling into their skull, opening it up and mucking around in there, no matter how beneficial that surgery might ultimately be for them.  Everyone wants a painless, uncomplicated, out-patient treatment with a guarantee of 100% effectiveness and of course, no complications.  That is a fantasy.  Let's be realistic: AN surgery is fraught with possible complications but, as I often try to warn some newbies clinging to the idea that radiation is a walk in the park with no possible ramifications, GK, CK and FSR are not without some risks.

I had surgery and radiation and had few qualms about the radiation.  If I happen to develop cancer due to the radiation treatment, I'll have to deal with that.  However, the radiation was necessary and I had no fears having it...and don't regret doing so.  The fact that I'm retirement age is admittedly a factor in my attitude regarding radiation but like anyone, I would like to be around as long as possible and certainly don't want a cancer diagnosis at any time in my life. 

We always support whatever treatment a patient chooses and try to keep it real and not favor any specific treatment.  We avoid substituting opinion for fact and don't subscribe to playing 'what if?' when no scientific evidence is presented, as is sometimes the case with the radiation/cancer position.  Meanwhile, radiation treatment for Acoustic Neuromas is gaining in popularity as the malignancy fears fade with time.  However, I doubt AN surgery is going to disappear any time soon.

Jim

[Tumbleweed]

   First, Lorenzo mentioned CK being used in the 90's but I don't believe that to be accurate since CK was FDA approved in 2001.

Actually, I think Lorenzo was correct. Dr. Chang told me that they've been using CK since 1994 (I presume in clinical trials) and that it was approved by the FDA in 1999.

JB, thanks for the great research quote on the relatively low malignancy risk associated with RS.

Best wishes to all,
Tumbleweed

[Sue]

Great subject.  Great answers.  All I know is that I think the risk of dying is greater going to and from your treatment than from the treatment itself!   Also, the risks of dying under anesthesia  is less than 1 in 200,000.  Don't know exactly how that compares to the AN statistic, but 6 known cases out of how many radiations?  It's got to be a lot.  Anyway....interesting subject. 

Sue in Vancouver USA