The use of radiotherapy (RT) was associated with an overall survival benefit in patients with prostate cancer and lymph node involvement who underwent radical prostatectomy and were also treated with androgen-deprivation therapy (ADT), according to a new study.
Approximately 12% of prostate adenocarcinoma patients have regional lymph node involvement at diagnosis. “This is a heterogeneous group with ultimately poor cancer-related outcomes,” wrote study authors led by Naresh Jegadeesh, MD, of Emory University in Atlanta. “Despite the prevalence of lymph node involvement, there is a dearth of high-level evidence available to guide genitourinary oncologists in its optimal management.” Limited research has suggested that RT after extended pelvic lymph node dissection could be effective, but in the United States extended dissection is uncommon.
The new study was a retrospective analysis of 2,569 patients with N1M0 prostate cancer included in the National Cancer Database; of those 906 patients (35.3%) received RT, and the study’s median follow-up was 53 months. Results of the analysis were published online ahead of print in Cancer.
Fewer patients over the age of 65 received RT (P < .001) than younger patients. RT was used more frequently when fewer lymph nodes were involved (P < .001), and those with private insurance or who were treated in nonacademic centers were also more likely to receive RT. The use of RT increased over the course of the study period (P < .001).
The 5-year overall survival rate was 87% in those who received RT along with ADT, compared with 82% in those who received ADT alone (P = .007). This association was maintained on a multivariate analysis, with a hazard ratio (HR) of 1.50 (95% CI, 1.18–1.90).
A propensity score-matched analysis yielded 826 patients in each group; in this cohort, the 5-year overall survival rate was 88% with RT, and 81% without, for an HR of 1.43 (95% CI, 1.10–1.86).
“Given the growing body of retrospective evidence, there is a pressing need for a prospective, randomized trial evaluating locoregional treatment for lymph node–positive prostate cancer,” the authors concluded, adding that in the absence of such high-level evidence these new results can help guide treatment management.
In an accompanying editorial, Ronald C. Chen, MD, MPH, of the University of North Carolina at Chapel Hill, agreed that “the time is right” to design a prospective clinical trial to determine optimal treatment. “This is an exciting new frontier in which the continued development of treatments and genomic tests can be used potentially to cure more patients with aggressive disease and maybe even to help individualize decisions regarding how aggressive treatment needs to be for each patient,” he wrote.