Clinical Investigation
Increasing Age and Treatment Modality Are Predictors for Subsequent Diagnosis of Bladder Cancer Following Prostate Cancer Diagnosis

https://doi.org/10.1016/j.ijrobp.2009.09.055Get rights and content

Purpose

To determine the effect of prostate cancer therapy (surgery or external beam irradiation, or both or none) on the actuarial incidence of subsequent bladder cancer.

Methods and Materials

The Surveillance, Epidemiology, and End Results registry from 1973 to 2005 was analyzed. Treatment was stratified as radiotherapy, surgery, both surgery and adjuvant radiation, and neither modality. Brachytherapy was excluded.

Results

In all, 555,337 prostate carcinoma patients were identified; 124,141 patients were irradiated; 235,341 patients were treated surgically; 32,744 patients had both surgery and radiation; and 163,111 patients received neither modality. Bladder cancers were diagnosed in: 1,836 (1.48%) men who were irradiated (mean age, 69.4 years), 2,753 (1.09%) men who were treated surgically (mean age, 66.9 years); 683 (2.09%) men who received both modalities (mean age, 67.4 years), and 1,603 (0.98%) men who were treated with neither modality (mean age, 71.8 years). In each treatment cohort, Kaplan-Meier analyses showed that increasing age (by decade) was a significant predictor of developing bladder cancer (p < 0.0001). Incidence of bladder cancer was significantly different for either radiation or surgery alone versus no treatment, radiation versus surgery alone, and both surgery and radiation versus either modality alone (p < 0.0001). On multivariate analysis, age and irradiation were highly significant predictors of being diagnosed with bladder cancer.

Conclusions

Following prostate cancer, increasing age and irradiation were highly significant predictors of being diagnosed with bladder cancer. While use of radiation increased the risk of bladder cancer compared to surgery alone or no treatment, the overall incidence of subsequent bladder cancer remained low. Routine bladder cancer surveillance is not warranted.

Introduction

There are nearly 220,000 new prostate cancer diagnoses each year (1). Some patients with favorable prognosis prostate cancer choose active surveillance without any directed therapy. Most patients, however, chose aggressive treatment (2) with either radiation therapy, surgery, or in some cases surgery followed by radiation therapy.

Since aggressive therapy carries attendant but differing morbidity 3, 4, 5, 6, patients must carefully consider the risks and side effects of each treatment modality. Given the excellent long term disease-free survival (7) and quality of life outcomes with either surgery- or radiation-based approaches 8, 9, consideration of the late effects of therapy is appropriate. A particularly worrisome potential effect of prostate irradiation is radiation-induced second malignancy. Studies reporting the incidence of bladder cancer following prostate cancer 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 have yielded conflicting results, with both positive and negative study outcomes. Several publications have shown that bladder cancer incidence increases following prostatic external beam irradiation 10, 14, 19, 20, 21, 22. On the basis of such positive studies, some authors argue for early and frequent bladder cancer surveillance (24).

However, aside from treatment modality, there are other confounders that may contribute to the risk for subsequent bladder cancer diagnosis after a diagnosis of prostate cancer. Increasing age, smoking, common etiologic genetic factors, and intensity and duration of follow-up have been implicated 17, 25, 26.

This analysis of the Surveillance, Epidemiology, and End Results (SEER) registry was performed to determine the effects of types of prostate therapy (external beam irradiation, surgery, both, or neither) on the actuarial incidence of bladder cancer. These data could be used to (1) counsel patients about their risk of developing bladder cancer over a variety of time points and (2) generate risk-stratified, follow-up guidelines.

Section snippets

Methods and Materials

The SEER program database was used to identify patients for this study. Data from 1973 to 2005 from 17 SEER tumor registries were used (San Francisco [Oakland Standard Metropolitan Statistical Area], Connecticut, Metropolitan Detroit, Hawaii, Iowa, New Mexico, Seattle [Puget Sound], Utah, Metropolitan Atlanta, Alaska, San Jose-Monterey, Los Angeles, rural Georgia, greater California, Kentucky, Louisiana, and New Jersey). Cases were available only for 1974 to 2005 for Seattle (Puget Sound), for

Results

A total of 555,337 patients were diagnosed with pathology confirmed prostatic carcinomas in the SEER database from 1973 to 2005. These data exclude patients who received any brachytherapy as a part of treatment for prostate cancer. Also excluded were patients diagnosed with simultaneous bladder and prostate cancers. This includes 137 patients treated with radiation alone, 631 patients managed surgically, 144 men who received both surgery and radiation, and 280 men who did not receive either

Discussion

This SEER database review is the largest to evaluate the risk of subsequent bladder cancer following diagnosis of prostate cancer, with over 555,000 men included. Men were evaluated for their risk for bladder cancer according to the type of treatment received (external beam irradiation, surgery, both, or neither). To our knowledge, this is the first study to investigate the risk for subsequent bladder cancer after combined surgery and adjuvant external beam irradiation. The overall incidence of

Conclusions

Following prostate cancer, increasing age and irradiation were highly significant predictors of being diagnosed with bladder cancer. These analyses confirm that the actual risk of subsequent bladder cancer following use of radiation in the treatment of prostate cancer is very low. The actuarial statistics provided can be used in informed decision making with patients prior to treatment and in considering the need for cystoscopic surveillance in men following treatment. The low overall incidence

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Conflict of interest: none.

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