Clinical Impact of the Number of Treatment Cycles in First-Line Docetaxel for Patients With Metastatic Castration-Resistant Prostate Cancer.
We investigated the impact of the number of docetaxel cycles administered in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with first-line chemotherapy.



Charts from 421 consecutive patients who initiated standard treatment with docetaxel-based chemotherapy (75 mg/m2every 3 weeks) between 2007 and 2013 were reviewed. Patients who received < 6 cycles of docetaxel were excluded from the analysis. Remaining patients were divided into 2 groups on the basis of whether or not ≥ 9 cycles of docetaxel were administered (n = 108 and 184, respectively). Reasons for treatment discontinuation and postdocetaxel treatments were registered. Prostate-specific antigen (PSA) responses were defined as a confirmed ≥ 50% decrease in baseline PSA levels. Overall survival (OS) was calculated from start of therapy using the Kaplan-Meier method. Cox proportional hazards were calculated to estimate the effect of clinical variables on OS.



OS was longer in patients treated with ≥ 9 cycles of docetaxel (21.9 months vs. 17.2 months; P < .0001, log rank). Survival also favored patients treated with ≥ 9 cycles of docetaxel when only patients ending docetaxel because of toxicity or treatment conclusion (22.3 vs. 19.4 months; P = .048, log rank) or patients who achieved a PSA response (22.3 vs. 18.7 months; P = .012, log rank) were evaluated. mCRPC-related prognostic factors and patients who received ≥ 1 subsequent line of therapy post-docetaxel were well balanced.



On the basis of our retrospective findings, a superior OS was found in patients treated with ≥ 9 cycles of docetaxel when adjusting for known prognostic factors. Dose reductions might increase the number of docetaxel cycles administered.
Department of Oncology, Herlev University Hospital, Herlev, Denmark. Electronic address: per.kongsted@regionh.dk.
Per
P
Kongsted
Department of Oncology, Herlev University Hospital, Herlev, Denmark.
Inge Marie
IM
Svane
Department of Oncology, Herlev University Hospital, Herlev, Denmark.
Henriette
H
Lindberg
Department of Oncology, Herlev University Hospital, Herlev, Denmark.
Lisa
L
Sengeløv
D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D000077143:Docetaxel; D004334:Drug Administration Schedule; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000378:metabolism; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy* / Q000378:metabolism; D012189:Retrospective Studies; D016019:Survival Analysis; D043823:Taxoids / Q000008:administration & dosage* / Q000627:therapeutic use; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D043823:Taxoids; D000077143:Docetaxel; D017430:Prostate-Specific Antigen
Chemotherapy; Dose reductions; Efficacy; Treatment duration; mCRPC