ASCO 2023: Assessing Racial Differences in Time to Treatment Escalation Following Androgen-Deprivation Therapy Among Veterans with Prostate Cancer

(UroToday.com) The 2023 American Society of Clinical Oncology (ASCO) annual meeting held in Chicago, IL between June 2nd and June 6th was host to a prostate, testicular, and penile cancers poster session. Dr. Nadine Friedrich presented the results of an analysis evaluating racial differences in time to treatment escalation following ADT among veterans with prostate cancer.


Despite the emergence of doublet and triplet therapy combinations for the management of patients with metastatic hormone sensitive prostate cancer (mHSPC), ADT remains the backbone treatment of such patients and, in “real-world” practice, the majority of patients with advanced/metastatic prostate cancer are initially treated with ADT alone. Currently, there are no population-level studies assessing the duration of treatment with 1st line ADT and the time to subsequent treatment escalation to chemotherapy, novel hormonal therapy, or non-steroidal antiandrogens.

In this study, the authors performed a retrospective population-level analysis evaluating the association between race and subsequent time to treatment escalation following the initial use of ADT, within the setting of the Veterans Affairs Health Care System. Between 2001 and 2021, 164,477 patients diagnosed with prostate cancer and treated with ADT alone were identified. Baseline demographic and clinical characteristics were summarized/analyzed by race: Caucasian, African American, Hispanic, or other. Categorical and continuous variables were compared using the Chi-square and Kruskal-Wallis tests, respectively. The primary outcome was treatment escalation, defined as receipt of novel hormonal therapy, non-steroidal anti-androgens, and/or chemotherapy. Time to treatment escalation was defined from the time of ADT initiation. Men without evidence of treatment escalation were censored at time of death or last recorded visit. The 5-year event rates by race were evaluated using Kaplan-Meier (KM) curves. The associations between race and time to treatment escalation were evaluated using univariable and multivariable Cox proportional hazards regression modeling. The multivariable model was adjusted for age, year, time from prostate cancer diagnosis to start of ADT, Charlson Comorbidity Index, BMI at ADT start along with PSA, testosterone level, and receipt of radiation therapy prior to ADT.

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On univariable analysis, African American patients were the youngest, started ADT in more recent years, had the highest pre-ADT PSA and testosterone levels, had the most comorbidities, and were the most likely to receive radiation therapy prior to ADT, compared to the other racial/ethnic groups. At a median follow-up of 55.2 months (IQR: 25- 102.4 months), 31,288 patients (19%) underwent treatment escalation, of which 39% were to NHTs, 47% to NSAAs, 12% to chemotherapy, and 2% to other 2nd line therapies. Compared to Caucasian patients, African American patients had significantly lower rates of treatment escalation both on univariable (HR:0.89, 95% CI: 0.87 – 0.92) and multivariable analyses (HR:0.82, 95% CI: 0.80 – 0.84). The Kaplan-Meier curves demonstrated that the 5-year freedom-from treatment escalation rates were 80.5% and 83% for Caucasian and African American patients, respectively. The corresponding 5-year rates for Hispanic patients and those of other races were similar to those of Caucasians, with 5-year rates of 81%.

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This study assessing racial differences in time to treatment escalation of men receiving 1st line ADT found that African Americans had significantly lower rates of treatment escalation. Whether this decreased rate of treatment escalation represents improved outcomes (i.e., lower rates of progression) or undertreatment requires further study.

Presented by: Nadine Adriana Friedrich, MD, Postdoctoral Research Fellow, Cedars-Sinai Medical Center, Los Angeles, CA

Written by: Rashid Sayyid, MD, MSc – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, Chicago, IL, Fri, June 2 – Tues, June 6, 2023.