Comparison of 2-Weekly and 3-Weekly Dosing of Docetaxel in Metastatic Prostate Cancer

Docetaxel 75 mg/m² every 3 weeks is the standard schedule for metastatic prostate cancer (mPC). Alternative dosing of 50 mg/m² every 2 weeks may be an option for frail patients. Our aim is to define which factors influence the choice of schedule and to compare the outcomes of both schedules in daily clinical practice.

We retrospectively included patients with mPC treated with docetaxel in our institution. We compared data from patients treated with 3-weekly, 75 mg/m² docetaxel or 2-weekly, 50 mg/m² docetaxel, including basal characteristics, predefined prognostic factors, treatment received, toxicity and survival data.

We included 200 patients, 86% of whom presented castration resistant mPC. A total of 158 patients (79%) were treated with 3-weekly scheme. Compared with these patients, patients treated with 2-weekly scheme were significantly older, had higher Eastern Cooperative Oncology Group performance status (ECOG PS) and Charlson Comorbidity Index, presented more visceral metastases and needed opioid treatment more frequently. Patients treated with 2-weekly scheme presented shorter median overall survival; however, these differences were not shown after multivariate analysis with significant prognostic factors. Patients treated with 2-weekly scheme had more treatment delays and suspensions, but less clinically impairing toxicities such as febrile neutropenia, neuropathy and diarrhea; toxic deaths were 5 in the 3-weekly group while none in the 2-weekly group.

Compared to docetaxel 75 mg/m² every 3 weeks, dosing of 50 mg/m² every 2 weeks may be an alternative for older, frailer and more comorbid patients. Two-weekly dosing may be used more frequently in selected patients.