ASCO GU 2018: Real-World Experience with Docetaxel for Castration-Sensitive Prostate Cancer from a Population-Based Analysis

San Francisco, CA (UroToday.com) Phase III clinical trials have demonstrated efficacy with an overall survival (OS) benefit for the addition of docetaxel (DOC) to androgen deprivation therapy (ADT) for the treatment of metastatic castration-sensitive prostate cancer (mCSPC). The clinical effectiveness of DOC with ADT in the general patient population remains undefined.


Methods:

The authors report a population-based retrospective review of patients with mCSPC who received DOC from 04/2015 to 02/2017. Safety and clinical-effectiveness were evaluated.

Results:

A total of 183 records were identified; 156 patients received DOC in the mCSPC setting. Baseline characteristics included a median age of 67 years (range 44-86) and visceral metastases (mets) were present in 18%. 80% had high volume disease with 74% having > 3, and 54% > 10 bone mets; 76% had de-novo metastatic disease. All 6 planned DOC cycles were delivered to 126 patients (81%). Treatment was stopped early due to toxicity in 15 (10%), unrelated death in 1 (0.6%), patient preference in 5 (3%) or disease progression in 9 (6%) cases. Dose reductions and delays were required in 61 (39%) and 25 (16%) patients, respectively. Grade 3-5 adverse events were noted in 62 (40%) patients, with 28 (18%) due to febrile neutropenia (FN); there were no treatment-related deaths. Patients with FN had more bone mets (p = 0.046), but there was no difference in time from start of ADT to initiation of docetaxel, age, baseline performance status, PSA, or visceral involvement. PSA ≤ 0.2 ng/L was achieved in 41 (28%) patients after 6 months of ADT and maintained in 13 (8%) patients after 12 months. 41% of patients had developed castrate resistant prostate cancer (CRPC) within 1-yr, with a median time to CRPC of 14.3 months. Treatment for CRPC was given in 54 patients, with most of them receiving either abiraterone or enzalutamide (87%) with a PSA decline of over 50%.

Conclusions:

The authors concluded that effectiveness of DOC with ADT in a general population of patients with mCSPC was associated with poorer outcomes and high rates of toxicity compared to the results reported in phase III studies. Response rates to first-line treatment for mCRPC with abiraterone or enzalutamide appear similar to those previously reported.


Presented by: Jean-Michel Lavoie, MD, Vancouver, Canada

Co Authors: Kevin Zou, Daniel Khalaf, Bernhard J. Eigl, Christian K. Kollmannsberger, Joanna Vergidis, Krista Noonan, Muhammad Zulfiqar, Daygen L. Finch, Kim N. Chi; British Columbia Cancer Agency - Vancouver Centre, Vancouver, BC, Canada; British Columbia Cancer Agency, Vancouver, BC, Canada; British Columbia Cancer Agency - Vancouver Island Centre, Victoria, BC, Canada; British Columbia Cancer Agency - Fraser Valley Centre, Surrey, BC, Canada; British Columbia Cancer Agency - Abbotsford Centre, Abbotsford, BC, Canada; British Columbia Cancer Agency - Centre for the Southern Interior, Kelowna, BC, Canada; BC Cancer Agency, Vancouver, BC, Canada

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre @GoldbergHanan at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA