A 70 year-old gentleman comes to see you after a recent diagnosis of localized prostate cancer. He has decided to forgo watchful waiting and pursue active treatment, but he has heard that the two options he is considering – external beam radiation therapy and prostatectomy – are both associated with adverse effects. Your patient explains that he leads an active life and is otherwise healthy, and asks which option will interfere least with his daily functioning.
An article in this week’s NEJM seeks to answer exactly that question. In their article, “Long-Term Functional Outcomes after Treatment for Localized Prostate Cancer,” Matthew J. Resnick and colleagues examined a cohort of 1655 men between the ages of 55 and 74, diagnosed with prostate cancer in the mid-1990s, who were treated with either prostatectomy (1164 men) or radiotherapy (491 men) and followed for fifteen years. At diagnosis, as well as at one, two, five, and fifteen years afterwards, the men were asked to complete a survey about their urinary, bowel, and sexual function. In general, radiotherapy is associated with an increased risk of bowel problems and surgery increases a patient’s risk of urinary incontinence and impotence. However, no study has followed patients for more than five years to find out which, if either, of these two treatments is associated with a higher risk of any adverse effect over the long term. Importantly, there has been no direct comparison of the two treatments in a randomized controlled trial, and this study was not randomized and did not look at how well patients did or did not respond to their treatments. The focus of the study was late effects of treatment.
Their findings were intriguing. While patients who had received a prostatectomy were significantly more likely to experience urinary incontinence and erectile dysfunction 2 and 5 years after treatment compared to patients who had received radiotherapy, they were no more likely to experience these problems after 15 years. Similarly, patients who had received radiotherapy were significantly more likely to experience bowel urgency at 2 and 5 years than those who had received a prostatectomy. However, those differences were no longer statistically significant after 15 years.
The study had several limitations. The first survey the participants filled out required them to retrospectively assess their urinary, bowel, and sexual function, so these evaluations may not have been accurate representations of each patient’s function before diagnosis. Most importantly, no untreated control group was included. As the authors explain, “although we evaluated the comparative harms of prostatectomy and radiotherapy, the precise contribution of prostate cancer treatment to age-dependent changes in urinary, sexual, and bowel function remains unknown, given the absence of an untreated, age-matched control cohort.” In essence, it was not possible to discern what proportion of these changes were due to aging alone.
While the implications of these findings for patient care are difficult to predict, they will likely be dependent on the goals individual patients set for their own care. Regardless, they give us new and important information with which we can educate patients about the adverse effects associated with two treatments for localized prostate cancer.