Men with prostate cancer with positive surgical margins or extracapsular extension achieved longer biochemical RFS; after radical prostatectomy with adjuvant radiotherapy compared with surgery alone; according to results of a randomized Finnish study published in European Urology. Researchers observed the greatest benefit among men with pT2 disease and positive margins and those with Gleason scores of 5 to 7.
“Prostate cancer may generate metastases and, in the worst case; therefore result in death more than 10 years after the recurrence of the disease, detected from a PSA increase,” Greetta Hackman, Lic. Med., of the faculty of medicine at University of Helsinki, said in a press release. “Given that the patients in this study monitored for less than 10 years on average; it is only natural that the treatment we studied did not have a significant impact on survival. In even longer follow-up; a difference in PSA increases could also lead to a difference in mortality.”
Men to adjuvant radiotherapy
However, for the randomized, open-label trial, Hackman and colleagues enrolled 250 men between April 2004; and October 2012 from eight Finnish hospitals. The men, all of whom had undergone radical prostatectomy, had pT2N0M0 prostate cancer with positive surgical margins or pT3aN0M0 disease (with or without positive margins) with no seminal vesicle invasion; preoperative PSA no higher than 20 µg/L and postoperative PSA less than 0.5 µg/L.
But the researchers randomly assigned the men to adjuvant radiotherapy at 66.6 Gy (n = 126; median age, 61 years; interquartile range [IQR], 57-65) or observation (n = 124; median age; 62 years; IQR, 59-65). But biochemical RFS served as the primary endpoint. Researchers hypothesized that, after 2 years of follow-up; 80% of men in the radiotherapy group and 60% in the observation group would remain biochemical progression-free.
OS, cancer-specific survival, local recurrence and adverse events served as secondary endpoints. Median follow-up for surviving participants was 9.3 years (range, 3.3-12.6) in the adjuvant group and 8.6 years (range, 3.6-12.1) in the observation group. But results showed 10-year biochemical RFS rates of 82% for the radiotherapy group vs. 61% for the observation group (HR = 0.26; 95% CI, 0.14-0.48), with 10-year OS rates of 92% vs. 87% (HR = 0.69; 95% CI, 0.29-1.6).
Two metastatic cancers
Two metastatic cancers occurred in the adjuvant group vs. four in the observation group. But of the 43 men in the observation group who experienced biochemical recurrence, 37 underwent salvage radiotherapy. Grade 3 adverse events occurred among 56% of men in the adjuvant group vs. 40% in the observation group (P = .016). However, these included erectile dysfunction (37% vs. 28%) and urinary incontinence (12% vs. 5%). But there was only one grade 4 adverse event, a compartment syndrome, which occurred in the adjuvant group.
However, the researchers cited the low number of patients as the study’s main limitation. Hackman noted that it is important for clinicians to discuss treatment options with patients, and to inform them of potential adverse events. “ More treatment also means more side effects,” she said in the release. “However, at the same time, we can likely influence the disease’s prognosis in a situation in which the cancerous tissue already extends to the prostate’s surface or has penetrated through the prostate’s capsule but has not yet metastasized.”