A Two‐Factor Bedside Prognostic Score Integrating Eastern Cooperative Oncology Group (ECOG) Performance Status and Aggressive Metastatic Burden in Metastatic Hormone‐Sensitive Prostate Cancer

BACKGROUND: Metastatic hormone-sensitive prostate cancer (mHSPC) remains clinically heterogeneous despite upfront treatment intensification. The commonly used CHAARTED high-volume and LATITUDE high-risk criteria stratify metastatic burden but do not explicitly incorporate Eastern Cooperative Oncology Group (ECOG) performance status (PS). We developed and internally assessed a simple bedside prognostic score integrating PS with aggressive metastatic burden in a real-world mHSPC cohort. METHODS: We retrospectively identified consecutive patients with histologically confirmed prostate adenocarcinoma who initiated first-line androgen deprivation therapy (ADT)-based systemic therapy for mHSPC between January 2014 and May 2025. Metastases were assessed primarily by conventional imaging (bone scintigraphy and computed tomography [CT]). The PS-Metastatic Burden score (0-2) assigned 1 point each for ECOG PS ≥ 1 and for aggressive metastatic burden defined as bone scan extent of disease (EOD) ≥ 3 and/or liver metastasis. The primary endpoint was overall survival (OS). Model fit and discrimination were compared with CHAARTED and LATITUDE using Akaike information criterion (AIC) and Harrell's concordance index (C-index) in a common complete-case dataset. RESULTS: Among 886 patients (median follow-up 36.9 months), 218 deaths occurred. Score distribution was 0/1/2 points in 592 (66.8%)/257 (29.0%)/37 (4.2%). OS was clearly separated across groups (log-rank p < 0.001): median OS was not reached for score 0 during follow-up; it was 49.0 months for score 1, and 37.3 months for score 2. In complete cases (n = 869; deaths = 211), hazard ratios versus score 0 were 2.16 (95% confidence interval [CI] 1.62-2.87) for score 1 and 3.08 (95% CI 1.87-5.08) for score 2 (both p < 0.001). The PS-Metastatic Burden score showed superior performance (AIC 2513.2; C-index 0.600) compared with CHAARTED and LATITUDE; adding PS to those frameworks improved performance modestly but remained inferior. Upfront androgen receptor pathway inhibitor (ARPI) use was lower in ECOG PS ≥ 1 than PS 0 (38.4% vs 60.8%; p < 0.001), and best supportive care initiation or death increased stepwise across score groups (21.3%, 37.2%, 51.4%). CONCLUSIONS: A two-factor bedside score integrating host reserve and aggressive metastatic burden provides pragmatic prognostic stratification for real-world mHSPC in the upfront ARPI era and offers information beyond CHAARTED/LATITUDE. External validation is warranted.