The doublet combination of docetaxel and ADT is currently approved for patients with mHSPC, following the results of the CHAARTED and STAMPEDE trials that demonstrated an OS benefit with this combination compared to ADT alone.1,2 Docetaxel is currently given for up to 6 cycles. However, it remains unclear if additional cycles of docetaxel are associated with improved oncologic outcomes. Furthermore, the safety/adverse event profile of additional treatment cycles remains poorly described.
This was a retrospective, single center analysis of patients with mHSPC treated at a German tertiary care center between 2018 and 2022. All patients received first-line treatment with ADT and docetaxel (75 mg/m2), given intravenously on the first day of each 21-day cycle. A subset of patients was treated beyond the standard 6 cycles. Baseline clinical and pathologic variables were abstracted. The following outcomes were evaluated, with T0 defined as the time of treatment initiation:
- Treatment-related toxicity
- PFS1: Progression-free survival on Docetaxel/ADT
- PFS2: Progression-free survival on subsequent therapy
- Overall survival
Survival analysis with Kaplan-Meier curves was employed, with the log-rank test used for between group comparisons.
This study included a total of 88 mHSPC patients, with a median follow up of 12 months. Mean age was 66 years (range: 50 – 83). Grade Group 4 disease was present in 78%, CHAARTED high volume in 69%, and LATITUDE high-risk in 74%. Of the 88 patients, 56 received 6 or less cycles of docetaxel (mean number of cycles: 5.2, with 5% receiving 1-2) and 32 received >6 cycles (7-8 cycles: 25%, 9-10 cycles: 75%, mean 9.2 cycles).
The frequency of toxicities did not significantly differ between the groups. From an oncologic efficacy standpoint, there were no significant differences in median PFS1 (14.0 versus 13.7 months) or PFS2 (5.5 versus 8.9 months).
Median OS in the standard docetaxel group was 40 months, whereas it was not yet reached in the extended docetaxel group.
Based on these results, the authors concluded that extended docetaxel treatment beyond 6 cycles is not associated with superior oncologic outcomes, although treatment-related toxicity appears to be comparable as well. Furthermore, overall survival data for such a comparison remains immature and future studies will be needed to further evaluate this.
Presented by: Can Aydogdu, MD, Department of Urology, Klinikum der Universität München, Munich, Germany
Written by: Rashid K. Sayyid, MD, MSc – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2023 American Urological Association (AUA) Annual Meeting, Chicago, IL, April 27 – May 1, 2023
References:
- Clarke NW, Ali A, Ingleby FC, et al. Addition of docetaxel to hormonal therapy in low- and high-burden metastatic hormone sensitive prostate cancer: long-term survival results in the STAMPEDE trial. Ann Oncol 2019 Dec 1;30(12):1992-2003.
- Kyriakopoulos CE, Chen YH, Carducci MA, et al. Chemohormonal therapy in metastatic hormone-sensitive prostate cancer: Long-term survival analysis of the randomized phase III E3805 CHAARTED trial. J Clin Oncol 2018 Apr 10;36(11):1080-1087.