Prognostic factors and treatment choice for stage IV, low-volume metastasis hormone-sensitive prostate cancer: cross-sectional study of real-world data

Background: Many metastatic prostate cancer prognostics have been suggested, but few are validated. Nodal metastasis burden and baseline biochemical characteristics are overlooked in the currently accepted stratifications for metastatic hormone-sensitive prostate cancer (mHSPC). Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) is likely to increase the incidence of pelvic nodal and mHSPC undetected by conventional scans. However, there is no consensus on managing regional nodal metastasis (N1M0) and no separate guidelines for non-regional nodal (M1a) and low-volume bone (M1b) spread but collectively as a part of low-volume CHAARTED disease.

Objectives: To assess the different prognostic factors for stage IV disease classified as CHAARTED low-volume on a real-world series of patients and to examine treatment preference for each of the disease subcategories.

Methods and design: This retrospective cross-sectional study included patients diagnosed with HSPC at stage IV, with low-volume disease according to the CHAARTED criteria. Data were collected from the database of Portsmouth and St. Mary NHS Hospitals between February 2017 and August 2023. Patient characteristics were analysed, and prognostic factors were evaluated using Cox regression analysis. 5-year progression-free survival (PFS) was the primary outcome measure.

Results: Data on 126 patients were analysed. Seven patients (6%) had N1M0, 28 (22%) M1a, and 91 (72%) M1b. 5-year PFS was 80.9% for M1a and 54.9% for M1b metastases, p = 0.3. High prostate-specific antigen (PSA) value (⩾25) was identified as an independent prognostic factor for PFS with HR = 2.80 (95% CI: 1.19-6.56), p = 0.0179. Variable treatment preference for each subclass reflects the uncertainty regarding the best regimen and the importance of consolidation prostate radiotherapy (cRT) in clinical practice.

Conclusion: Early results of our data analysis underscore the significance of baseline PSA as an independent prognostic factor alongside anatomical tumour extent of spread in stage IV low-volume metastasis prostate cancer. There is no agreement on treatment for each subcategory, necessitating further real-world studies and clinical trials. Further follow-up would assess the prognostic benefit of cRT.