Tolerance and Oncological Outcomes of In-Field Reirradiation for Locally Recurrent Breast Cancer: A Long-Term Single-Center Experience.

Background: The management of cancer relapse in previously irradiated tissues is a challenging therapeutic issue. The aim of this work was to report our experience with breast reirradiation for locoregionally recurrent breast cancer.

Methods: All patients who underwent breast or chest wall in-field reirradiation at the Institut Curie, Paris, France, between 2003 and 2019, were identified. Efficacy outcomes and physician-reported toxicities were retrospectively assessed.

Results: A total of 21,372 patients underwent breast irradiation in our institution. Of these, 28 received a second course of radiotherapy to the homolateral breast/chest wall. A total of 18 (64%) patients were treated with a curative intent, and 10 (36%) were treated for palliative purposes. Only one acute and one late grade 3 adverse events were reported. One patient with major cardiovascular risk factors died of myocardial infarction 13 months after left breast reirradiation. The 2-year LRFS, OS, DSS, PFS and MFS were 59%, 79%, 82%, 46% and 75%, respectively, in the whole cohort. The 2-year LRFS (72% vs. 31%, = 0.02), OS (94% vs. 50%, < 0.01), DSS (94% vs. 56%, < 0.01) and PFS (61% vs. 20%, = 0.02) differed significantly between patients treated with curative or palliative intent but not the MFS (78% vs. 69%, = 0.77). Among the patients, eight (29%) remained relapse-free 5 years after reirradiation.

Conclusion: Breast/chest wall reirradiation appears to be feasible with good disease control, especially in patients treated with a curative intent, and presents acceptable toxicity rates.