Adjuvant Radiotherapy Benefits Survival in Subsets of Patients With Node-Positive Prostate Cancer
In an analysis of outcomes in patients with node-positive prostate cancer reported in the Journal of Clinical Oncology, Abdollah et al found that adjuvant radiotherapy is associated with a survival benefit in patients with low-volume nodal disease in the setting of intermediate- to high-grade non–specimen-confined disease and in patients with intermediate-volume nodal disease irrespective of other tumor characteristics.
Study Details
The study involved 1,107 patients with pN1 prostate cancer treated with radical prostatectomy and anatomically extended pelvic lymph node dissection between 1988 and 2010 at the Mayo Clinic in Rochester, Minnesota, and San Raffaele Hospital in Milan. All patients received adjuvant hormonal therapy with or without adjuvant radiotherapy.
Improved Cancer-Specific Survival
In total, 35% of patients received adjuvant radiotherapy. On multivariate analysis, adjuvant radiotherapy was associated with a significantly lower risk of prostate cancer–specific mortality (hazard ratio [HR] = 0.37, P < .001). Stratification into risk groups showed that the survival benefit was limited to two groups of patients, consisting of: patients with two or more positive nodes, Gleason score 7 to 10, pT3b/pT4 stage, or positive surgical margins (HR = 0.30, P = .002) and patients with three to four positive nodes regardless of other tumor characteristics (HR = 0.21, P = .02).
Similar Findings for Overall Survival
Findings were similar in multivariate analysis of overall survival, with adjuvant radiotherapy being associated with significantly reduced risk of overall mortality in patients with two or more positive nodes, Gleason score 7 to 10, pT3b/pT4 stage, or positive surgical margins (HR = 0.42, P = .001) and in those with three to four positive nodes (HR = 0.32, P = .02) and not in other defined risk groups.
The investigators concluded: “The beneficial impact of [adjuvant radiotherapy] on survival in patients with pN1 prostate cancer is highly influenced by tumor characteristics. Men with low-volume nodal disease ([two or more positive lymph nodes]) in the presence of intermediate- to high-grade, non–specimen-confined disease and those with intermediate-volume nodal disease (three to four [positive lymph nodes]) represent the ideal candidates for [adjuvant radiotherapy] after surgery.”
Alberto Briganti, MD, of San Raffaele Scientific Institute, Milan, is the corresponding author for the Journal of Clinical Oncology article.
The authors indicated no potential conflicts of interest.
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