Prognostic Factors and Risk Stratification in Patients With Castration-Resistant Prostate Cancer Receiving Docetaxel-based Chemotherapy

Shimpei Yamashita; Yasuo Kohjimoto; Takashi Iguchi; Hiroyuki Koike; Hiroki Kusumoto; Akinori Iba; Kazuro Kikkawa; Yoshiki Kodama; Nagahide Matsumura; Isao Hara

Disclosures

BMC Urol. 2016;16(13) 

In This Article

Methods

Patients and Treatment

Patients with CRPC treated with docetaxel chemotherapy at the Wakayama Medical University Hospital (Wakayama, Japan) from June 2005 to May 2014 were included in this study. The eligibility criteria included histopathologically diagnosed adenocarcinoma of the prostate and confirmed failure of prior androgen deprivation therapy. If PSA increased after confirmation of the existence of antiandrogen withdrawal syndrome and alternative antiandrogen therapy, we judged that prior androgen deprivation therapy was a failure. No patient was administered abiraterone or enzalutamide or sipuleucel-T. In general, patients received 70 mg/m2 of docetaxel intravenously every 3 or 4 weeks. The recommended dose of docetaxel in the NCCN guidelines is 75 mg/m2, however the 70 mg/m2 dose is commonly used in Japan. This is because severe myelosuppression is more likely to develop in Japanese than Europeans and Americans. If necessary, dose reduction and interval extension were allowed, based on the patient's overall condition. Prednisone 5 mg was routinely administered twice daily simultaneously with hormonal therapy for medical or surgical castration. Treatment with docetaxel was continued until disease progression, unacceptable adverse events, or the patient's refusal. Disease progression was defined as increases in the number of evaluable lesions observed or in size of existing lesions by RECIST 1.1 on imaging tests and/or biological progression characterized by an elevated serum PSA level of 25 % and an absolute increase of ≥2 ng/mL than the nadir. As a general rule, PSA increase required at least two times.

This study was approved by the institutional review board of Wakayama Medical University (approval number 1672). Written informed consent to participate in this study was not obtained from patients since this study was a retrospective observational study for ordinary medical practice. Instead, information about this clinical study was disclosed at the web page of our hospital and posted at visitor consultation rooms in our hospital. If patients refused the use of their clinical data, we should have excluded their data from our study. However, no patient refused to provide his data for our study.

Assessment

The variables, including patients' characteristics at diagnosis (serum PSA level, Gleason score, and metastatic sites) and characteristics at the start of chemotherapy (age, ECOG performance status (PS), significant clinical pain, precedent treatment, serum PSA level, duration from initiation of androgen deprivation therapy, complete blood count, biochemical profile, combined drugs) were collected retrospectively. The NLR was calculated from the circulating neutrophil and lymphocyte counts. The CRP-to-albumin ratio was calculated from the CRP value and the albumin value using the formula: CRP value/albumin value) × 100.

The goal of the of the study was to determine the effect of patient characteristics on OS, calculated as the interval between the first day of docetaxel administration and the date of death or the last follow-up visit for censored (living) patients.

Statistical Analysis

All statistical analyses were performed using SPSS software. OS was determined according to the Kaplan-Meier method. Univariate and multivariate analyses of OS were performed to compare the prognostic factors in a Cox proportional hazards analysis. Continuous data were divided into 2 groups according to their median values. P < 0.05 was considered significant.

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