Contemporary post-prostatectomy radiation therapy for prostate cancer within a statewide quality consortium.
Authors: Samuel Regan, Michael Dykstra, Huiying Yin, Mark A. Zaki, Mazen Mislmani, Patrick McLaughlin, Danielle Kendrick, Sarah Paluch, Andrea Smith, David K. Heimburger, Matthew J. Schipper, William C. Jackson, Robert Timothy Dess
Journal: Journal of Clinical Oncology (2025)

369 Background: The 2024 AUA Salvage Therapy for Prostate Cancer Guideline provides guidance at the time of suspected recurrence after radical prostatectomy (RP). Recommendations include early initiation of post-operative radiation therapy (RT), and the addition of androgen deprivation therapy (ADT) for those with high-risk features. Given that an increasing number of men receive RP for high-risk disease, we characterized RT in a prospective cohort from the Michigan Radiation Oncology Quality Consortium (MROQC) and the Michigan Urological Surgery Improvement Collaborative (MUSIC). Methods: Patients who received post-RP RT at an MROQC center from 06/09/20 – 09/18/24 were eligible. The MUSIC database provided surgical pathology variables, and MROQC prospectively collected data via patient-, physician-, and physicist-completed forms. RT was defined as adjuvant (pre-RT PSA &lt;0.1 ng/mL), consolidative (persistently elevated PSA post-RP), or salvage. Multivariable analyses (MVA) were used to evaluate associations between ADT intent and patient and clinical features, including high risk features (pT3b/T4, pN1, grade group (GG) 4/5, pre-RT PSA &gt;0.5 ng/mL, consolidative). Results: A total of345 patients at 26 centers received RT. The median pre-RT PSA was 0.3 ng/mL (IQR: 0.2-0.6); PET staging was done in 60%, and 34% had genomics testing. RT was adjuvant in 10% (n = 35), consolidative in 28% (n = 95), and salvage in 62% (n = 215). Median pre-RT PSA in each subgroup was 0.07 (IQR: 0.03-0.09), 0.5 (IQR: 0.3-1.5), and 0.3 (IQR: 0.2-0.5) ng/mL, respectively (p=0.005). Median time to RT post-RP was 8, 6, and 29 months, respectively. Most patients (62%) had at least one high risk feature including pT3b (24%), pN1 (5%), GG 4/5 (30%), Pre-RT PSA &gt;0.5 ng/mL (27%), and PSA persistence (28%). Consolidative patients had worse pathologic features compared to salvage patients: pT3b (35% vs. 15%), pN1 (9.5% vs. 0.5%), GG 4/5 (42% vs. 24%), and pre-RT PSA (0.5 vs. 0.3 ng/mL), p&lt;0.01 for all. Sixty percent (n = 204) were prescribed ADT, with an intended duration of ≤6 months in 133 men (65%) and ≥24 months in 34 (17%). On MVA, ADT use was positively associated with high-risk features including pN1 (OR 6.22 [95% CI 1.35 – 47.57]), pT3b/T4 (ref. pT2, OR 2.77 [95% CI 1.34 – 5.93]), GG 4/5 (ref. GG 1/2, OR 2.87 [95% CI 1.51 – 5.56]), pre-RT PSA ≥0.5 ng/mL (OR 2.11 (95% CI 1.17 – 3.91]). ADT was less often used with adjuvant RT (ref. salvage, OR 0.17 [95% CI 0.06 – 0.45]). Conclusions: In a contemporary statewide quality consortium, salvage RT was delivered at a PSA ≤0.5 in nearly 75% of patients, and ADT use was associated with high-risk features. Importantly, 62% of patients have at least one high-risk feature, and over 25% received consolidative RT for persistently positive PSA. Optimized treatment strategies are needed for this at-risk population that has been underrepresented on many modern trials.