Second Tumar after Prostate Cancer Therapy?

Less occurrence of bladder and colon cancer after brachytherapy than after surgery and radiation

The risk to develop a bladder or colorectal cancer as a secondary tumor after radiation, e.g., brachytherapy, is lower than developing a second cancer after complete removal of the prostate. This is the result shown in a current U.S. study that has recently been published in the renowned British Journal of Urology.

The fear that after successful treatment of prostate cancer, a secondary tumor develops is deeply ingrained in many men. Especially radiotherapeutic procedures are in disrepute to favor the occurrence of colon and bladder cancer. "Wrongly so”, says Dr. Pedram Derakhshani, urologist at the West German Prostate Center. Thanks to the state-of-the-art radiation therapy process, it is now possible to optimally protect healthy tissue from radiation damage.

The question of how high the actual risk is to develop a secondary cancer after prostate cancer therapy, has now been examined by researchers from the Memorial Sloan-Kettering Cancer Center in New York1. The researchers analyzed data from a total of 2658 patients. Of these, 1348 underwent a radical removal of the prostate, 897 an external radiation, and 413 brachytherapy. The results clearly show that secondary tumors occur relatively infrequent.  For example, a reoccurrence of cancer was detected in an average of 10 to 15 percent of the patients ten years after the treatment. Most frequently occurring were thereby bladder or rectal tumors. The risk was 3% in the operated patients, 4% in patients who received external irradiation, and in patients having received brachytherapy it was only 2%.

Precisely accurate radiation
"Newer and much more targeted techniques such as brachytherapy assure today that bowel and bladder are not within the radiation field," says Dr. Derakhshani. "Cutting-edge computer technology and the use of imaging techniques allow us to detect the target area and to irradiate it with millimeter accuracy." Thus, in brachytherapy unlike the external radiation, the smallest radiation sources (seeds) are implanted directly into the tumor. The seeds remain there for several months disbursing a high-dose radiation targeting the tumor tissue. "The advantage here is that the tumor is destroyed without damaging the surrounding healthy tissue or organs such as bladder, colon, or sphincter," says the Cologne urologist.

An additional factor is that radiation-induced changes in the genome of healthy cells often occur only decades later.  "The majority of the irradiated cancer patients are at the time of their illness already in the second half of their lives", says Dr. Derakhshani.  Again, this should always be taken into consideration when comparing potential risks with the benefit of treatment.Nevertheless, with regard to follow-up treatments, it is important to pay attention to secondary cancers", the Cologne's urologist emphasizes. Bladder and rectum should be examined at regular intervals.

1Zelefsky MJ, Pei X, Teslova T, Kuk D, Magsanoc JM, Kollmeier M, Cox B, Zhang Z: Secondary cancers after intensity-modulated radiotherapy, brachytherapy and radical prostatectomy for the treatment of prostate cancer: incidence and cause-specific survival outcomes according to the initial treatment intervention. BJU Int. 2012 Aug 13.