Stratification of Prognoses based on Criteria from Clinical Trials of Metastatic Hormone-sensitive Prostate Cancer
Abstract Background: Oncologic outcomes in metastatic hormone-sensitive prostate cancer (mHSPC) are extremely heterogeneous. We aimed to (1) stratify the prognosis in mHSPC patients according to criteria for high-volume disease, as defined in clinical trials, and (2) identify the combinations of unfavorable risk factors.Methods: This retrospective study reviewed 623 patients who were diagnosed with mHSPC between 1996 and 2014. The prognoses of mHSPC patients were stratified by criteria from the GETUG15, CHAARTED, STAMPEDE, and LATITUDE trials. The exclusion criteria were incomplete clinical data, docetaxel chemotherapy with upfront options, and metastatic disease without proper management after initial diagnosis.Results: All 485 patients (median follow-up=36.1 months) were categorized according to stage: M1a (70, 14.4%), M1b (367, 75.7%), and M1c (48, 9.9%). Significant differences in overall survival (OS) and cancer-specific survival (CSS) were found among the groups with low-volume disease, as classified by four clinical trials (log-rank p=0.001 and p<0.001, respectively). Bone metastasis volume and liver metastasis were independent predictors of prognosis. According to disease classification under NCCN guidelines, the prognosis of CSS between low-volume disease patients and M1c patients (no bone metastasis and low-volume bone metastasis) was not significantly different. Additionally, the prognosis of CSS did not significantly differ between M1c (high-volume bone metastasis and visceral metastasis, except liver) and M1b (high-volume bone metastasis) patients.Conclusions: The prognoses of patients with low-volume disease, based on several classification systems, were heterogeneous. Except for lung or liver metastasis, the combination of visceral metastasis with no/low-volume bone disease should be considered as a proxy of less aggressive disease in patients presenting with mHSPC.