Feasibility of 4 Cycles of Docetaxel and Cyclophosphamide Every 14 Days as an Adjuvant Regimen for Breast Cancer: A Wisconsin Oncology Network Study

Adjuvant therapy for breast cancer can be improved by increasing dose density. We tested the feasibility of delivering dose-dense docetaxel-cyclophosphamide (TC) in a single-arm phase II trial of 42 patients via the Wisconsin Oncology Network. Treatment was safe, tolerable, and most patients completed therapy as plan- ned. Thus, this commonly used regimen can be delivered in 8 weeks. Introduction: Dose-dense therapies have had a major effect on reducing toxicity and improving outcomes in breast cancer. A combination of TC every 3 weeks has emerged as a common chemotherapy regimen used for treatment of node-negative or lower-risk node-positive breast cancer. We tested whether it is feasible to deliver TC on a dose- dense schedule, with therapy completed within 10 weeks. Patients and Methods: We enrolled women with early stage breast cancer on a single-arm phase II study of adjuvant dose-dense TC through a regional oncology network. All women completed primary surgery before accrual, and subsequent therapy with TC was deemed appropriate by the treating physician. Planned treatment was docetaxel 75 mg/m 2 plus cyclophosphamide 600 mg/m 2 every 2 weeks for 4 cycles with subcutaneous pegfilgrastim 6 mg administered 24 to 48 hours after the administration of each chemotherapy cycle. Results: Of 42 women enrolled, 41 were evaluable using prespecified criteria. Of these, 37 (90.2%) completed therapy within 10 weeks and 34 (83%) completed therapy at 8 weeks without dose modification. Rates of neuropathy were similar to that reported previously. The rate of neutropenic fever was low (2.5%). Rash and plantar-palmar erythrodythesia were common and reached grade 3 in 4 subjects (9.8%). Conclusion: Dose-dense TC is feasible with tolerability profiles similar to standard TC and a low likelihood of neutropenic fever. This study supports further clinical development of this 8-week adjuvant chemotherapy regimen.