(UroToday.com) The 2023 ASCO annual meeting included a prostate cancer session, featuring a presentation by Dr. Susan Halabi discussing the relationship between a priori defined prognostic risk groups and overall survival (OS) in men with metastatic hormone sensitive prostate cancer (mHSPC). Prior analyses have shown that men who present with high volume disease and de novo metastases have shorter OS compared with other mHSPC subgroups. This analysis aimed to determine the prognostic relationship between a-priori defined 4-prognostic groups and OS in men with mHSPC and in a subset of trials in patients treated with ADT + docetaxel. This hypothesis was investigated by the STOPCAP M1 collaborators.
Dr. Halabi and colleagues obtained individual patient data from 8 randomized trials (12 comparisons) comparing treatment regimens (ADT or ADT + docetaxel in the control or research arms) in mHSPC:
OS was defined as the time between date of randomization and date of death/or last follow-up. Patients were classified into four mutually exclusive groups. Poor prognostic risk-group was defined as high volume (presence of visceral metastases, and/or > 4 bone metastases or presence of bone metastases beyond pelvic or vertebral bones) plus synchronous diagnosis. Intermediate risk groups were patients with high volume and metachronous (intermediate A) or low volume plus synchronous diagnosis (intermediate B). Lastly, good risk group had low volume plus metachronous disease:
The proportional hazards model was used to estimate the hazard ratio (HR) and assess the prognostic significance of risk groups in predicting OS adjusting for treatment.
Among 6,041 patients included in this analysis, 60% (3,622 patients) had died over a median follow-up of 5 years. Overall, 11%, 8%, 47%, and 34% were in the good, intermediate A, intermediate B, and poor risk groups, respectively, and for trials including docetaxel (n=2,627 patients) 9%, 5%, 39%, and 47% respectively. Hazard ratios of OS in all cohorts and docetaxel subgroups are as follows:
The Kaplan-Meier OS plots by risk groups are as follows:
Dr. Halabi concluded her presentation discussing the relationship between a priori defined prognostic risk groups and OS in men with mHSPC with the following take-home points:
- Differences in OS across the risk groups were observed
- Further work is needed to investigate if more precise prognostic groups can be defined such as better characterization of patients' groupings of extent of bone metastases and visceral metastases
Presented by: Susan Halabi, PhD, Duke University Medical Center, Durham, NC
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, Chicago, IL, Fri, June 2 – Tues, June 6, 2023.