External beam radiation for men with prostate cancer appears to result in a small, but definite risk of bladder cancer and rectal cancer- so concludes Dr. Paul Nam and colleagues from the University of Toronto.
Dr. Nam and co- workers reviewed 3,056 published papers and selected 21 studies for more refined analysis. Their conclusion was that external beam radiation increased the chances for a second cancer 5 to 10 years down the road.
Dr. Nam and colleagues readily admit that most of the included studies had “moderate bias.” Nonetheless, men who had external beam radiation for their prostate cancers had an increased risk of bladder cancer ranging from 0.1% to 3.8%. Their risk of rectal cancer varied from 0.3% to 1.2%. Their study was reported in the British Medical Journal, March 2, 2016 issue.
BUT NOT ALL RADIATION FOR PROSTATE CANCER IS EQUAL.
In the accompanying editorial to the study, Dr. Zeitman and Dr. Eyler from Harvard, pointed out the importance of radiation dose to surrounding organs, like the bladder and rectum. Collateral damage to bladder and rectum is key. In fact, men with prostate cancer who underwent radiation implants, with little or no dose to the bladder or rectum, had no such increased risk for a second cancer. Fortunately, as Drs. Zeitman and Eyler point out in their editorial, cancer of the bladder and rectum can be caught early by screening and can be readily cured.
SO WHAT IS A MAN WITH PROSTATE CANCER TO DO?
With Cyber Knife, we can achieve the same sparing of bladder and rectum as with radiation implants. So for men with early stage and intermediate risk prostate cancer, I believe Cyber Knife may be their best choice. Cyber Knife has the same cure rates as external beam radiation and far fewer embarrassing side effects. In fact, First Dayton Cancer Care is the only Cyber Knife center in Southwest Ohio whose planning system and treatments mimics that of temporary implants.
For our men with high risk prostate cancer- men who need IMRT and a boost by either temporary implants or Cyber Knife- I think the benefits of combined radiation treatments dwarf the small risk of a second cancer.
And now that we know the risks, it’s even more important to screen our prostate cancer survivors for bladder and rectal cancer in the future- all part of our survivorship plan.
If you have any questions about your prostate cancer, please feel free to call me, Dr. Edward Hughes, at 855- DAYTON 1.