Toxicity of concurrent radiotherapy with CMF chemotherapy in the E-CMF adjuvant breast carcinoma regimen

582 Background: In the adjuvant management of breast cancer although delivery of radiotherapy (RT) concurrently with anthracyclines is contraindicated, toxicities are acceptable when the chemotherapy regimen used is CMF. The NEAT trial (NEJM 2006; 355:1851- 1862), presented at ASCO in 2003 demonstrated a significant survival advantage for sequential 4x epirubicin and 4x CMF chemotherapy (E- CMF) compared with 6x CMF and was adopted in the UK as a standard regimen. In order to limit treatment duration, RT may be given concurrently with chemotherapy during the CMF phase of treatment. We have reviewed the toxicity associated with this approach. Methods: Retrospective review of all patients treated with concurrent breast RT and CMF chemotherapy as part of the E-CMF regimen in our institution. Toxicities were graded according to the Radiation Therapy Oncology Group (RTOG) toxicity criteria. Confidence intervals were calculated by the binomial method using Stata version 9. Results: 77 patients received concurrent therapy between March 2004 and May 2006. Baseline characteristics; median age: 48, ER positive: 63.5%, HER2 positive: 11.7%, node positive disease: 85.7%. Type of surgery; lumpectomy: 61.0%, mastectomy: 39.0%, nodal dissection: 100%. Chemotherapy delivery; completed without delay: 35.1%, completed therapy with dose reduction/delay: 48.1%, discontinued therapy prematurely due to toxicity 16.8%. Sites of RT; breast: 62.3%, chest wall: 35.1%, axillary nodes: 45.5%, supraclavicular fossa: 36.4%. Schedule of RT; 50Gy/25#: 18.2%, 46/45Gy/20#: 67.6%, 45Gy/15#: 14.3%. Median interval between final dose of epirubicin and start of RT: 55 days. Toxicity; cutaneous grade 3–4 acute radiotherapy toxicity: 31.2% (95%CI 21.1–42.7%); cutaneous infective cellulitis: 14.3% (95%CI 7.4–21.1%); grade 3–4 neutropenia: 54.4% (95%CI 42.8–65.9%); febrile neutropenia requiring hospitalisation: 22.1% (95% CI 13.4–33.0%). The median duration of stay in hospitalised patients was 8 days (range 3–23 days). Conclusions: Toxicities were significantly greater than documented previously for concurrent therapy. RT should not be given concurrently with CMF chemotherapy as part of the E-CMF regimen. No significant financial relationships to disclose.