Use of helical tomotherapy in locally advanced and/or metastatic breast cancer for locoregional treatment.

objectiveHelical tomotherapy (HT) is a new promising tool whose use remains to be studied. This work assesses its impact for local irradiation in terms of side effects, as well as tumour control in locally advanced (LABC) and metastatic breast cancer (MBC).

methodsWe retrospectively reviewed data of 66 patients with LABC and MBC. Patients received standard fractionated radiotherapy by HT, with or without concurrent systemic treatment.

resultsThe median age was 60 years (28-77). The median follow-up of the population was 35.9 months (10.6-95.8). For 91% of patients, HT was concomitant with systemic treatments. Three patients experienced grade 3 skin toxicity and all had concurrent 5FU-vinorelbine. One patient who was receiving concurrent treatment with trastuzumab-pertuzumab had a decreased left ventricular ejection fraction by 14%. No late cardiac or lung toxicity was observed. A clinical benefit was observed in 75% of cases. At 2 months after HT, we observed tumour regression in 7/8 patients, as following: 1 complete, 4 partial responses, and 2 stable disease. The median survival for MBC group was 64.4 months (42.6-65.8) and 21.1 (6.1-36.1) months for LABC.

conclusionThis study suggests that the use of HT is well tolerated and feasible with a multimodal strategy that includes concurrent systemic treatments for patients with LABC and MBC. Advances in knowledge: The survival of LABC and MBC increases and new safe tools are needed to determine optimal strategies of treatment. To our knowledge, this is the first paper describing the use of HT for this population.