Definitive Radiation Therapy and Survival in Clinically Node-Positive Prostate Cancer

• Published in: International journal of radiation oncology, biology, physics Vol. 101; no. 5; pp. 1188 - 1193
• Main Authors: Bryant, Alex K., Kader, Andrew K., McKay, Rana R., Einck, John P., Mell, Loren K., Mundt, Arno J., Kane, Christopher J., Efstathiou, Jason A., Murphy, James D., Rose, Brent S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2018
• Subjects: Aged; Androgen Antagonists - therapeutic use; Cohort Studies; Databases, Factual; Disease-Free Survival; Hospitals, Veterans; Humans; Incidence; LYMPH NODES; Lymph Nodes - pathology; Lymphatic Metastasis; Male; Middle Aged; Multivariate Analysis; Neoplasm Metastasis; NEOPLASMS; Proportional Hazards Models; PROSTATE; Prostate-Specific Antigen - blood; Prostatic Neoplasms - mortality; Prostatic Neoplasms - radiotherapy; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Time Factors; Treatment Outcome
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2018.04.023

The survival benefit of combined radiation therapy (RT) and androgen deprivation therapy (ADT) compared with ADT alone for clinically lymph node–positive prostate cancer remains controversial. We identified patients with clinically node-positive, nonmetastatic prostate cancer diagnosed between 2000 and 2015 and treated with ADT (n = 450) or ADT-RT (n = 198) from a national Veterans Affairs database. We compared prostate cancer–specific mortality (PCSM) and all-cause mortality (ACM) between treatment groups using multivariable competing-risks regression and Cox regression, respectively. An interaction term between ADT-RT and prostate-specific antigen (PSA) level (dichotomized about the median) was included in the multivariable models. ADT-RT was associated with improved PCSM among patients with PSA levels less than the median of 26 ng/mL (sub-distribution hazard ratio, 0.50; 95% confidence interval [CI] 0.28-0.88; P = .02) but not greater than the median (hazard ratio [HR], 1.15; 95% CI 0.67-1.96; P = .62) (P = .038 for interaction). ADT-RT was also associated with improved ACM among patients with PSA levels less than the median (HR, 0.38; 95% CI 0.25-0.57; P < .001) but not greater than the median (HR, 0.91; 95% CI 0.60-1.38; P = .66) (P = .004 for interaction). Definitive treatment with ADT-RT is associated with improved PCSM and ACM among patients with clinically node-positive prostate cancer and lower baseline PSA levels. Patients with clinically node-positive disease appear to be a heterogeneous cohort, with a subset who may achieve long-term survival with combined RT and ADT.