Is re-irradiation combined with chemotherapy an option for inoperable local recurrence of previously irradiated breast cancer? A collection of cases

BACKGROUND: The rate of locoregional recurrence after primary therapy remains at 5-15%. Ipsilateral recurrences are most commonly located in the residual breast or chest wall, followed by isolated nodal axillary and supraclavicular recurrences at 1-3%. In pre-irradiated patients with inoperable recurrences, re-radio(chemo)therapy can achieve sufficient local tumor control. METHODS: All inoperable patients with histologically confirmed locoregional recurrence (LRR) who underwent salvage radio(chemo)therapy at the University Medical Center Freiburg were included in this analysis. A descriptive assessment of toxicity and oncological endpoints was performed. RESULTS: A total of seven patients were identified. The LRRs were located as follows: two in the chest wall, three parasternal/sternal, and two supraclavicular. The LRRs occurred after a median of 99 (3-311) months after completion of primary therapy. In four patients, additional osseous involvement (per continuitatem) was diagnosed. The mean dose of prior radiation was 59.7 Gy. All patients received normofractionated percutaneous radiotherapy, with a simultaneous integrated boost with a single dose of 1.7-2 Gy up to a total dose of 50.4-60 Gy, if necessary. Five patients received concomitant chemotherapy with 5‑fluorouracil (FU)/capecitabine. Staging and target volume definition were based on PET-CT or MRI imaging. The median follow-up was 14.8 (1-76) months. No high-grade toxicity ≥ 3 was observed. Acute and chronic toxicity grade 1-2 was limited to radiodermatitis, fatigue, restriction of arm elevation, and pain. Local tumor control was achieved in all patients. Visceral metastasis occurred in one woman. CONCLUSION: Re-irradiation with concurrent chemotherapy in inoperable LRR can achieve reliable local control. Our approach provides additional support for the existing evidence regarding the oncological benefit of combined postoperative radiotherapy and capecitabine in patients with triple-negative breast cancer. Given the established clinical tolerability of re-irradiation protocols, future efforts must prioritize the standardization of concurrent systemic treatments to optimize both safety and therapeutic outcomes in this setting.