Prognostic value of tumour volume based on [18F]PSMA-1007 PET/CT in prostate cancer.

Abstract

BACKGROUND: Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) enables sensitive detection and staging of prostate cancer, yet its relationship with long-term survival remains unclear. This study aimed to assess whether total lesion volume (TLV) measured on [18F]PSMA-1007 PET/CT predicts overall survival (OS) in prostate cancer patients. METHODS: A cohort of 282 patients scanned between 2019 and 2021 was retrospectively studied, including both patients undergoing primary staging and imaging for biochemical recurrence (BCR). Tumour lesions in the prostate/prostate bed, lymph nodes and bone were manually segmented and TLV was calculated for each compartment and as total of all lesions. Based on TLV, patients were categorized into three groups for each compartment: no detectable tumour, TLV ≤ median, and TLV > median. Bone analyses were dichotomised into any vs. no detectable tumour. The association with OS was assessed using age-adjusted Cox proportional-hazards models and Kaplan–Meier analysis, separately for the primary staging subgroup and the BCR subgroup. RESULTS: Over a mean follow-up of almost 5 years, 49 patients (17%) died. In the primary staging subgroup (n = 171), detectable bone metastases on PSMA PET-CT predicted poorer survival compared to no detectable bone metastasis (HR 2.39, p = 0.031). Among patients with BCR (n = 111), total TLV above the median and a prostate TLV above the median both predicted an almost 5 times increased risk of death. CONCLUSION: Total lesion volume on [18F]PSMA-1007 PET/CT was associated with OS, with different prognostic patterns in primary staging and BCR. The results support future incorporation of volumetric PSMA PET metrics into personalized staging and therapeutic decision-making.