1166 - Real-World Evidence across Prostate RT Modalities: Utilization Shifts, Toxicity and BCR in Genomic Classifier Scored Patients

05:35pm - 05:40pm ET

Room 205

Presenter(s)

Thomas Kole, MD, PhD - Memorial Sloan Kettering Monmouth, Middletown, NJ

T. P. Kole¹, Q. Joslove Xu², A. R. Barsky¹, J. Janopaul-Naylor¹, E. Bent¹, Z. R. Moore¹, D. J. Gorovets¹, V. S. Brennan¹, S. M. McBride¹, J. Haseltine¹, D. M. Guttmann¹, M. A. Kollmeier¹, J. Setton¹, M. B. Bernstein¹, X. Zhao², A. Moradi², Y. Liu², J. Proudfoot², E. Davicioni², and H. Nagar¹; ¹Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, ²Veracyte, Inc., South San Francisco, CA

Purpose/Objective(s): Hypofractionated radiation therapy (RT) regimens have become standard treatment options in the primary management of prostate cancer (PCa). We examined real-world data (RWD) to determine utilization trends, toxicity, and biochemical recurrence (BCR) across RT modalities in patients with genomic classifier (GC) scored PCa.

Materials/Methods: A retrospective analysis was conducted of a national clinical–genomic linkage of Decipher GC with longitudinal RWD (Veracyte, South San Francisco, CA). We identified 36,026 patients with biopsy GC scores who received primary RT for PCa between 2016-2025. External beam (EBRT) episodes were classified as conventional (CF, >35 fx), moderate hypofractionation (HF, 20-28 fx), and SBRT (=10 fx with CPT 77373). Brachytherapy episodes were classified as monotherapy (BM) and boost (BB, EBRT + brachy). Toxicity (GU, GI, sexual) was assessed via ICD-10 diagnostic and HCPCS procedural codes and defined as acute (=6 months after RT) or late (>6 months after RT). Multivariate logistic regression was used to examine associations between RT fractionation and toxicity. BCR was assessed using multivariate Cox models stratifying for treatment modality, NCCN risk, GC group, and ADT.

Results: Among 30,918 EBRT patients, CF utilization declined from 75.1% (2016) to 22.3% (2025), while HF and SBRT increased to 56.4% and 21.3%, respectively. Increases in HF were similar across all GC groups, whereas SBRT was more pronounced among GC low and decreases in CF were largest in GC low and intermediate groups. Compared to CF, both HF and SBRT demonstrated significantly lower adjusted all-grade GU toxicity (acute aOR: 0.72 and 0.47; late aOR: 0.60 and 0.57, all p<0.001), sexual toxicity (acute aOR: 0.73 and 0.51; late aOR: 0.65 and 0.58, all p<0.001), and late GI toxicity (aOR 0.77 and 0.71, both p<0.001). BM (n=3,851) had significantly lower adjusted all-grade GU, sexual, and GI acute/late toxicity compared to CF (p<0.001), whereas BB (n=1,257) had similar acute (p=0.916) and late (p=0.432) GI toxicity to CF. Despite uniformly low rates of urinary catheterization (<3%) across all modalities, patients with BB and BM had approximately 4 and 6-fold increased rates compared to SBRT, respectively. Toxicity was independent of GC for all modalities.

At a median follow-up of 21.2 months, BCR risk did not differ by EBRT (HF aHR 0.98, p=0.79; SBRT aHR 0.99, p=0.96) or BM (aHR 0.98, p=0.87) versus CF, while BB demonstrated the lowest adjusted BCR (aHR 0.41, p<0.001). BCR was independent of GC group in all modalities except CF where GC high patients demonstrated the highest risk of BCR (aHR 1.51, p=0.012).

Conclusion: In this large RWD cohort, EBRT utilization shifted from CF toward MF and SBRT. Hypofractionated approaches were associated with lower GU and sexual toxicity compared to CF with similar rates of BCR. Toxicity was independent of GC, however, predicted increased BCR risk in CF treated patients.