Radiation Therapy for Prostate Cancer Increases Subsequent Risk of Bladder and Rectal Cancer: A Population Based Cohort Study
Pre-prostate specific antigen era series demonstrated an increased risk of bladder cancer and rectal cancer in men who received radiotherapy for prostate cancer. We estimated the risk of secondary bladder cancer and rectal cancer after prostate radiotherapy using a contemporary population based cohort. We identified 243,082 men in the Surveillance, Epidemiology and End Results database who underwent radical prostatectomy or radiotherapy for prostate cancer between 1988 and 2003. We estimated the incidence rate, standardized incidence ratio and age adjusted incidence rate ratio of subsequent bladder cancer and rectal cancer associated with radical prostatectomy, external beam radiotherapy, brachytherapy, and a combination of external beam radiotherapy and brachytherapy. The relative risk of bladder cancer developing after external beam radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy compared to radical prostatectomy was 1.88, 1.52 and 1.85, respectively. Compared to the general United States population the standardized incidence ratio for bladder cancer developing after radical prostatectomy, external beam radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy was 0.99, 1.42, 1.10 and 1.39, respectively. The relative risk of rectal cancer developing after external beam radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy compared to radical prostatectomy was 1.26, 1.08 and 1.21, respectively. The standardized incidence ratio for rectal cancer developing after radical prostatectomy, external beam radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy was 0.91, 0.99, 0.68 and 0.86, respectively. Men who receive radiotherapy for localized prostate cancer have an increased risk of bladder cancer compared to patients undergoing radical prostatectomy and compared to the general population. The risk of rectal cancer is increased in patients who receive external beam radiotherapy compared to radical prostatectomy. Patients should be counseled appropriately regarding these risks.
- "The observed hazard ratio for radiation therapy and subsequent rectal cancer was 1.7 (18) Results from the SEER database estimated the relative risk of rectal cancer developing after EBRT, brachytherapy, and EBRT brachytherapy compared with radical prostatectomy to be 1.26, 1.08, and 1.21, respectively. (19) There is evidence that patients diagnosed with prostate cancer share an increased relative risk for primary bladder cancer occurrence irrespective of the treatment modality used. (20, 21) In the vast majority, the secondary bladder carcinomas are high grade and muscle invasive at diagnosis. "
[Show abstract] [Hide abstract] ABSTRACT: Literature about the risk of secondary cancer after radiation therapy (RT) of prostate and rectal cancer reveals contradictory results. We conducted a meta-analysis to examine whether the RT induces secondary rectal or prostate cancer in patients, respectively, with prostate or rectal cancer. All studies published in Medline or Pubmed up to March 3, 2015, containing RT of primary rectal or prostate cancer, and providing risk estimates of secondary prostate or rectal cancer were considered as eligible. Relative risk (RR) and standardized incidence ratios (SIR) were calculated using the random-effects model. Twenty studies met the inclusion criteria. 12 of them were from the Surveillance, Epidemiology, and End Results (SEER) database. For prostate cancer patients, pooled adjusted RRs or SIRs did not show an effect on the risk of secondary rectal cancer. However, notwithstanding the limitations of SEER-based studies, the subgroup of prostate cancer patients receiving external beam radiation therapy (EBRT) showed an increased risk of rectal cancer. For rectal cancer patients, pooled adjusted RR of prostate cancer was 1.12 (95 % CI, 0.44-2.8) and SIR was 0.40 (95 % CI, 0.29-0.55). All studies included in the SIR analysis of rectal cancer were derived from the SEER data source. Based on current evidence, RT for prostate cancer patients had no effect on rectal cancer incidence, except for patients who received EBRT therapy. However, compared with the general population, RT for rectal cancer is associated with a decreased prostate cancer risk as found in SEER-based studies.0Comments 0Citations
- "This bias is unlikely, because prostate cancer patients without RT did Overall (I-squared = 100.0%, p < 0.01) Huo D  Baxter NN  Kendal WS  Moon K  Brenner DJ  Prostate cancer, EBRT, SEER Nieder AM  1 "
- "The RISPC risk is still held to be variable and small for IMRT, however the effect has only begun to be investigated in recent years . Contemporary studies comparing newer forms of radiotherapy continue to find increased risk for RISPC for two-dimensional radiation therapy, most frequently of the bladder, however IMRT may have a reduced potential for RISPC despite conflicting experimental evidence [32, 33]. The analysis underscores the multitude of factors that underlie survival and the inherent complexity in estimating which patients will survive longer. "