Evaluation of the impact on overall survival curves of patients with metastatic castration-sensitive prostate cancer staged with PET-PSMA and classified according to current prognostic criteria by volume and risk.

Abstract

36 Background: The treatment of metastatic castration-sensitive prostate cancer (mCSPC) has evolved over the years. These therapies are guided by current volume (CHAARTED) and risk (LATITUDE) criteria, instituted based on conventional exams. The emergence of new imaging exams like PSMA PET, with its greater accuracy and early detection of metastatic disease, raises questions about the applicability of these criteria in this context. Methods: We conducted a retrospective, single-center study comparing patients staged with PSMA PET between August 2017 and February 2022 and classified as metastatic, after curative therapy or de novo metastatic. Patients with stage IVA, i.e., N1, were also included. Patients were stratified into high and low volume and risk, with the aim of comparing these prognostic factors with outcome of OS. Results: 48 patients with a median age of 66 years at diagnosis were selected: 81.3% had Gleason scores between 8 to 10, 57% had T classification greater than or equal to T3 and 32% were N1 by conventional exams. According to PSMA PET, 40% were de novo metastatic, with disease sites being bones (M1b - 52%), non-pelvic lymph nodes (M1a - 21%), pelvic lymph nodes (N1 - 17%), and viscera (M1c - 10%). 71% of them were low volume and 75% were low risk. With a median follow-up of 37.5 months and 7 deaths, at 36 months we had 64.6% of the high-volume population alive versus 96.6% of low-volume patients (p=0.054), 77.8% of high-risk patients alive compared to 89.9% of low-risk ones (p=0.739). There was a 67% increase in distant metastasis detection. When correlated with bone scintigraphy (BS), there was a 78.9% discordance between the number and/or location of bone lesions, and in 53.3% of cases, PSMA PET was positive for bone disease with negative BS at the same time. Conclusions: PSMA PET appears to be prognostic when applied to volume curves, despite p=0.054, which does not happen for risk, in addition to increasing the detection of metastatic disease compared to conventional exams and being more accurate in the detection of bone disease when compared to BS.