These were the findings of a retrospective cohort study in JAMA Network Open.
The standard treatment of advanced prostate cancer is androgen deprivation therapy (ADT). “The role of local therapy has been debated for several years. Studies have shown that radiation therapy or radical prostatectomy can improve patient survival under certain conditions,” said Hubert Kübler, MD, director of the Clinic and Polyclinic for Urology and Pediatric Urology at the University Hospital Würzburg in Germany. “At academic centers, a local therapy is pursued for oligometastatic patients if they are fit enough.”
The hope is to spare patients the side effects of ADT over an extended period and thus improve their quality of life. “But what impact does local therapy itself have on the men’s quality of life, especially considering that the survival advantage gained may be relatively small?” wrote study author Saira Khan, PhD, MPH, assistant professor of surgery at Washington University School of Medicine in St. Louis, Missouri, and her colleagues.
Examining Side Effects
This question has not been thoroughly examined yet. “To our knowledge, this is one of the first studies investigating the side effects of local therapy in men with advanced prostate cancer for up to 5 years after treatment,” wrote the authors.
The cohort study included 5500 US veterans who were diagnosed with advanced prostate cancer between January 1999 and December 2013. The tumors were in stage T4 (tumor is fixed or has spread to adjacent structures), with regional lymph node metastases (N1), and partially detectable distant metastases (M1).
The average age was 68.7 years, and 31% received local therapy (eg, radiation therapy, radical prostatectomy, or both), and 69% received systemic therapy (eg, hormone therapy, chemotherapy, or both).
Types of Local Therapy
Combining radiation therapy and radical prostatectomy “diminishes the meaningfulness of the study results,” according to Dr. Kübler. “The issue should have been analyzed in much finer detail. Studies clearly show, for example, that radiation therapy consistently performs slightly worse than prostatectomy in terms of gastrointestinal complaints.”
In their paper, the researchers reported that the prevalence of side effects was high, regardless of the therapy. Overall, 916 men (75.2%) with initial local therapy and 897 men (67.1%) with initial systemic therapy reported experiencing at least one side effect lasting more than 2 years and up to 5 years.
In the first year after the initial therapy, men who underwent local therapy, compared with those who underwent systemic therapy, experienced more of the following symptoms:
- Gastrointestinal issues (odds ratio [OR], 4.08)
- Pain (OR, 1.57)
- Sexual dysfunction (OR, 2.96)
- Urinary problems, predominantly incontinence (OR, 2.25)
Lasting Side Effects
Even up to year 5 after the initial therapy, men with local therapy reported more gastrointestinal and sexual issues, as well as more frequent incontinence, than those with systemic therapy. Only the frequency of pain equalized between the two groups in the second year.
“Our results are consistent with the known side effect profile [of local therapy] in patients with clinically localized prostate cancer receiving surgery or radiation therapy instead of active surveillance,” wrote the authors.
The comparison in advanced prostate cancer, however, is not with active surveillance but with ADT. “As the study confirmed, ADT is associated with various side effects,” said Dr. Kübler. Nevertheless, it was associated with fewer side effects than local therapy in this study. The concept behind local therapy (improving prognosis while avoiding local problems) is challenging to reconcile with these results.
Contradictory Data
The results also contradict findings from other studies. Dr. Kübler pointed to the recently presented PEACE-1 study, where “local complications and issues were reduced through local therapy in high-volume and high-risk patients.”
The study did not consider subsequent interventions, such as how many patients needed transurethral manipulation in the later course of the disease to address local problems. “There are older data showing that a radical prostatectomy can reduce the need for further resections,” Dr. Kübler added.
“I find it difficult to reconcile these data with other data and with my personal experience,” said Dr. Kübler. However, he agreed with the study authors’ conclusion, emphasizing the importance of informing patients about expected side effects of local therapy in the context of potentially marginal improvements in survival.
Different Situation in Germany
“As practitioners, we sometimes underestimate the side effects we subject our patients to. We need to talk to our patients about the prognosis improvement that comes with side effects,” said Dr. Kübler. He added that a similar study in Germany might yield different results. “Dr. Khan and her colleagues examined a very specific patient population: Namely, veterans. This patient clientele often faces many social difficulties, and the treatment structure in US veterans’ care differs significantly from ours.”
This article was translated from the Medscape German edition. A version of this article appeared on Medscape.com.