Publication Year: 2000

527

Adjuvant Cyclophosphamide, Etoposide and Cisplatin (CEP) Without STEM Cell Rescue as Consolidation for High Risk Localized Breast Cancer. Kristine J Rinn, Robert B Livingston, Julie R Gralow, Tove Thompson, Cheryl Vernon, Maggie Williams, Georgiana K Ellis, Univ of Washington, Seattle, WA; Puget Sound Oncology Consortium, Seattle, WA.

This study evaluated efficacy and feasibility of high-dose CEP without stem cell rescue. From 1991-1999, 115 patients (pts) with high-risk breast cancer received CEP on one of several protocols which varied by growth factors being evaluated. All received G/GMCSF or PIXY321 and an additional 17 received IL-11 or thrombopoetin. Pts had stage II/IIIA disease involving >10+ axillary LN, >4+ axillary LN following neoadjuvant chemotherapy, or IIIB (non-inflammatory) breast cancer (n=78); pts with IIIBc (inflammatory) disease were also enrolled (n=37). Median age=46 (30-66). Tumors were ER+/PR+/mixed in 77, ER-/PR- in 36 and unknown in 2. Overexpression of HER-2/neu (HER2) was present in 34 of 56 patients whose tumors were tested. All patients first received 4-6 months of doxorubicin-based (neo)adjuvant chemotherapy. Two cycles of CEP (cyclophosphamide 2.25g/m² d.4,5, etoposide 150mg/m² q 12º d.1-3, cisplatin 75 mg/m² d.1,5) were planned with 91 receiving both cycles and 24 just one (first cycle toxicity/patient refusal). Median hospital stay was 22-24 days/cycle. With median follow-up of 29 months (2-92), the 3-year projected DFS for all high-risk patients is 66% (95%CI 56-76%). The 3-year DFS in the 78 with stage II/III (non-inflammatory) is 68% (95%CI 56-80%) and for those with inflammatory disease is 59% (95%CI 42-73%). HER2+ and HER2- patients have identical DFS at this time. The mortality rate was 3.5% with 3 acute deaths (hemorrhage, RSV/fungal pneumonia) and 1 late death (pneumonitis). Excluding myelosuppression, 44% of patients had grade 4 toxicities (predominantly gastrointestinal). In conclusion, a non-transplant regimen using high-dose CEP as consolidation for high-risk breast cancer is feasible and has efficacy similar to autotransplant regimens reported from the ABMTR by Rowlings et al (1997), but does not show advantages in terms of efficacy, toxicity and cost. Further study in HER2+ patients may be warranted, as several groups report increased high-dose failures in this population.