Weekly and 3-Weekly Taxane Regimens in Metastatic Breast Cancer: Outcomes in Unselected Patients

Abstract

Objectives: Our main objective was to describe outcomes of taxane therapy in women with metastatic breast cancer treated in non-trial clinic settings. A second objective was to compare outcomes of two common taxane regimens, whose relative effectiveness was uncertain.

Design: Retrospective cohort of all female breast cancer patients treated with taxanes as first line therapy between January 2010 and December 2015 followed up until death or censor on 21^st March 2017. Community Health Index, ChemoCare(R) prescribing data, acute hospital discharge records, cancer registration and death records from National Records for Scotland were linked. Descriptive statistics, Kaplan-Meier and Cox proportional hazards models were used to assess survival.

Setting: Large UK cancer centre with 1.1 million population catchment area.

Participants: All female breast cancer patients treated with taxanes as first line therapy between January 2010 and December 2015 followed up until death or censor on 21^st March 2017.

Main Outcome Measures: Death from any cause.

Results: 260 women met the inclusion criteria, comprising 56 prescribed docetaxel 3-weekly and 204 prescribed paclitaxel weekly. Median follow-up 13 months (range 1 day to 6.7 years). Median survival was significantly longer in patients treated with docetaxel (1.48 years, 95% CI 1.19 to 2.18) compared with those on paclitaxel (0.91 years, 95% CI 0.78 to 1.23). In the first year of treatment, patients treated with paclitaxel had a 72% higher risk of death than those treated with docetaxel (HR 1.72, 95% CI 1.03 to 2.87) after adjusting for HER2 receptor status, socio-economic circumstances, age, time since diagnosis and Charlson Comorbidity Index. No significant difference in hazard ratios was observed between the groups after 1 year, although hazards were lower in the paclitaxel group. HER2 receptor positivity, age ≤ 50 years, and diagnosis ≤ 1 year before commencing treatment were associated with significantly better survival.

Conclusions: Women with metastatic breast cancer who are treated with taxanes have poorer survival if treated on weekly regimens compared with 3-weekly ones. The differences may be partially or wholly explained by differences in casemix. While randomised controlled trials continue to be the gold standard for determining the relative efficacy of different cancer regimens, our results will be helpful in better understanding the likely outcomes that patients will obtain in clinical practice.

Funding Statement: This study was funded by a grant from Breast Cancer Now, 2015NovSP691.

Declaration of Interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

Ethics Approval Statement: Data were obtained under a minor amendment of West of Scotland Research Ethics Committee 4 project reference 12/WS/0075.