Comparative longer-term functional outcomes of radical prostatectomy and external-beam radiation therapy for localized prostate cancer remain undefined. In a study recently reported in The New England Journal of Medicine,¹ Matthew J. Resnick, MD, and colleagues at Vanderbilt University, Nashville, compared urinary, bowel, and sexual function up to 15 years after prostatectomy or external-beam radiation therapy in men from the population-based Prostate Cancer Outcomes Study (PCOS) who had been diagnosed with localized cancer in the mid-1990s. The study showed that there is little difference in functional outcomes between the two types of treatment at 15 years, with decline in all functional domains being common over the long term.

Study Details

The PCOS enrolled 3,533 men diagnosed with prostate cancer in 1994 and 1995. The cohort for the current study consisted of 1,655 men in whom localized prostate cancer had been diagnosed between the ages of 55 and 74 years and who had undergone either surgery (n = 1,164) or external-beam radiation therapy (n = 491) as primary therapy (with or without androgen-deprivation therapy) within 1 year after diagnosis.

Patients had to have completed a 2-year or 5-year follow-up survey. Disease-specific outcomes were measured using multi-item rating scales, with each domain-specific summary scale scored from 0 to 100 (worse to better function). Odds ratios (ORs) for all outcome analyses were adjusted for age, baseline function, race/ethnic group, tumor grade, number of coexisting illnesses, education level, and propensity score.

At baseline, there were significant differences between the prostatectomy group and the radiotherapy group with regard to age (median of 64 vs 69 years, P < .001) and race/ethnic group distribution (white, black, and Hispanic for 76%, 12%, and 12%, respectively, vs 82%, 10%, and 8%, respectively; P < .001). Gleason scores tended to be lower in the prostatectomy group (2–4, 5–7, and 8–10 in 64%, 18%, and 6.5%, respectively, vs 59%, 22%, and 10%, respectively; P < .001), with the prostatectomy group also having fewer coexisting illnesses (0, 1, 2, and ≥ in 42.5%, 34%, 15%, and 8%, respectively, vs 33%, 33%, 17%, and 17%, respectively; P < .001). However, none of these differences was significant on analysis adjusting for propensity scores. There was no difference between groups in prostate-specific antigen level at baseline.

At the time of the 15-year survey, 27.7% of patients in the prostatectomy group and 50.3% of those in the radiotherapy group had died. Among living patients, survey response rates were 87.5% at 2 years, 83.3% at 5 years, and 60.3% at 15 years. More surviving patients in the surgery group responded to the 15-year survey (63.2% vs 51.0%).

Urinary Function

Patients in the surgery group were significantly more likely to have no urinary control or frequent urinary leakage at 2 years (9.6% vs 3.2%, OR = 6.22, 95% confidence interval [CI] = 1.92–20.29) and 5 years (13.4% vs 4.4%, OR = 5.10, 95% CI = 2.29–11.36), but not at 15 years (18.3% vs 9.4%, OR = 2.34, 95% CI = 0.88–6.23). Patients in the prostatectomy group were more likely at all time points to wear incontinence pads. The likelihood of being bothered by urinary incontinence was significantly higher in the prostatectomy group at 2 years (10.6% vs 2.4%, OR = 5.86, 95% CI = 1.93–17.64) and 5 years (12.9% vs 2.9%, OR = 7.66, 95% CI = 2.97–19.89), but no significant difference was observed between groups at 15 years (17.1% vs 18.4%, OR = 0.87, 95% CI = 0.41–1.80).

Mean summary scores decreased from 100 at baseline to approximately 80 in the radiotherapy group and to less than 70 in the prostatectomy group at 15 years among patients with normal baseline urinary function. Scores were higher in the radiotherapy group at years 1, 2, and 5.

Among patients with lower function at baseline, both groups had a baseline score of 70. The mean score initially increased in the radiotherapy group but then gradually declined to near baseline level by 15 years. Scores initially decreased in the prostatectomy group and then improved back to baseline levels by 1 year and gradually declined to a score of approximately 65 at 15 years. Scores were higher in the radiotherapy group at years 1, 2, and 5 by similar magnitudes.

Sexual Function

Patients in the surgery group were significantly more likely not to have erections sufficient for intercourse at 2 years (78.8% vs 60.8%, OR = 3.46, 95% CI = 1.93–6.17) and 5 years (75.7% vs 71.9%, OR = 1.96, 95% CI = 1.05–3.63), but there was no significant difference between groups at 15 years (87.0% vs 93.9%, OR = 0.38, 95% CI = 0.12–1.22). More patients in the prostatectomy group reported being bothered by sexual dysfunction at 2 years (55.5% vs 48.2%), 5 years (46.7% vs 39.7%), and 15 years (43.5% vs 37.7%), but none of these differences was statistically significant.

Among patients with higher sexual function summary scores at baseline (≥ 80), the mean score decreased from approximately 90 in both groups to approximately 20 to 25 at 15 years; scores were higher in the radiotherapy group at 1 and 2 years, nearly identical in the two groups at 5 years, and declined at a similar rate thereafter in both.

Among patients with lower baseline function, scores in the radiotherapy group decreased from approximately 43 at baseline to approximately 13 at 15 years, whereas those in the prostatectomy group decreased from approximately 53 to 15. Scores were higher in the radiotherapy group at 1 and 2 years, with scores in the two groups being nearly identical at 5 years.

Bowel Function

Significantly fewer patients in the prostatectomy group had bowel urgency at 2 years (13.6% vs 34.0%, OR = 0.39, 95% CI = 0.22–0.68) and 5 years (16.3% vs 31.3%, OR = 0.47, 95% CI = 0.26–0.84), with the difference no longer being significant at 15 years (21.9% vs 35.8%, OR = 0.98, 95% CI = 0.45–2.14). Significantly fewer patients in the prostatectomy group were bothered by frequent bowel movements, pain, or urgency at 2 years (2.9% vs 7.9%, OR = 0.37, 95% CI = 0.14–0.96) and at 15 years (5.2% vs 16.0%, OR = 0.29, 95% CI = 0.11–0.78), but not at 5 years (4.4% vs 5.8%, OR = 0.93, 95% CI = 0.27–3.22).

Among patients with normal bowel function at baseline, mean summary scores decreased from 100 to approximately 87 in the prostatectomy group and 83 in the radiotherapy group at 15 years. The difference between the two groups remained stable after 1 year, with scores being higher in the surgery group at years 1, 2, and 5. Among patients with lower function at baseline, scores improved from 72 in the prostatectomy group and 70 in the radiotherapy group to 82 and 78, respectively, at 1 year and remained fairly stable thereafter (approximately 82 and 77, respectively, at 15 years).

The authors concluded, “[M]en undergoing prostatectomy or [radiotherapy] for localized prostate cancer had declines in all functional outcomes throughout early, intermediate, and long-term follow up. Whereas short- and intermediate-term data reveal differences in functional profiles among men undergoing prostatectomy and [radiotherapy], at 15 years we observed no significant relative between-group differences. Considering the often long duration of survival after treatment for prostate cancer, these data may be used to counsel men considering treatment for localized disease. Furthermore, these data underscore the need for consideration of active surveillance in appropriately selected men with low-risk prostate cancer.” ■

Disclosure: Dr. Resnick has served as a consultant/advisor for Dendreon and Bayer Healthcare.

Reference

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