At 15 Years, Functional Declines Are Similar Regardless of Therapy Type for Prostate Cancer

David Penson, MD

In the short term, the selection of a therapy by patients with clinically localized prostate cancer can amount to a choice between potential declines in urinary and sexual function versus possible impairment in bowel function. However, 15 years after treatment, patients have roughly equal odds of experiencing declines in any of those functions, with no significant difference associated with their choice of either radical prostatectomy or external-beam radiation therapy, according to a recent study.

The study was needed because men with the condition are often eligible for either treatment, and while their prognosis is generally good, there have been no randomized trials comparing survival outcomes between the therapy types, senior study author David Penson, MD, professor of Urologic Surgery and Medicine at Vanderbilt University, and colleagues wrote. Therefore, they wrote, functional outcomes are an important factor in selecting a treatment.

The study included 1655 men who had been part of the Prostate Cancer Outcomes Study, in which patients diagnosed with the disease in the mid-1990s were followed prospectively for 15 years. Of the men chosen for the functional outcomes study, 1164 (70.3%) had undergone prostatectomy and 491 (29.7%) had undergone radiotherapy, all within a year of diagnosis. The men were between 55 and 74 years of age at diagnosis.

At 6 months after diagnosis, the men selected for Penson et al’s study had been asked to recall their prediagnosis urinary, sexual, and bowel function. Then, at 1, 2, 5, and 15 years after diagnosis, the surviving patients were surveyed about their clinical outcomes and quality of life.

Men who had undergone prostatectomy were more likely than radiotherapy patients to report urinary incontinence at 2 years (odds ratio [OR] = 6.22; 95% CI, 1.92-20.29) and 5 years (OR = 5.10; 95% CI, 2.29-11.36). At 15 years, the absolute difference in the prevalence of the problem was 18.3% for the prostatectomy group versus 9.4% for the radiotherapy group. Yet the authors “observed no significant difference in the adjusted odds of urinary incontinence (OR = 2.34; 95% CI, 0.88-6.23)” at 15 years, and wrote that, while the relative likelihood of patients feeling bothered by incontinence was higher in prostatectomy patients at 2 and 5 years, it was not significantly different at 15 years postdiagnosis.

Men in the prostatectomy group were also more likely than those in the radiotherapy group to report sexual dysfunction at 2 years (OR = 3.46; 95% CI, 1.93- 6.17) and 5 years (OR = 1.96; 95% CI, 1.05-3.63). But after 5 years, patients in both groups experienced a gradual decline of that function, and at 15 years, “erectile dysfunction was nearly universal,” affecting 87% of those in the prostatectomy group and 93.9% of those in the radiotherapy group, the authors reported. The OR for erectile dysfunction at 15 years was 0.38 (95% CI, 0.12-1.22) with no significant between-group difference, wrote Penson et al.

In the earlier years of the study, it was the radiotherapy patients who were more likely to experience bowel urgency, the authors added. At 2 years, the OR for that loss of function was 0.39 (95% CI, 0.22-0.68) and at 5 years, it was 0.47 (95% CI, 0.26-0.84). At 15 years, there were absolute differences in the prevalence of the problem between the prostatectomy group as compared with the radiotherapy group—21.9% versus 35.8%, respectively—and radiotherapy patients reported being significantly more bothered by bowel symptoms at both 2 and 15 years. However, at 15 years, the authors found no difference in the adjusted odds of having the problem between the two groups (OR = 0.98; 95% CI, 0.45-2.14).

Resnick MJ, Koyama T, Fan K-H, et al. Long-term functional outcomes after treatment for localized prostate cancer. N Engl J Med. 2013;368(5):436-445.