Adding immune checkpoint inhibitors to postoperative radiotherapy did not significantly increase radiation pneumonitis or radiation dermatitis in patients with triple-negative breast cancer, according to a preliminary single-centre retrospective analysis. The study did find nearly three times more hypothyroidism in the immunotherapy group.
What was known
Immune checkpoint inhibitors are already part of neoadjuvant treatment for triple-negative breast cancer, so postoperative radiotherapy is increasingly delivered while the patient is still on immunotherapy. The combination may increase the risk of radiation pneumonitis, but evidence on whether concurrent checkpoint inhibitors raise it in triple-negative disease was very limited.
What this study adds
Preliminary, single-centre (Hubei Cancer Hospital, Wuhan, China), retrospective and hypothesis-generating study in patients treated between 2022 and 2024. It included 132 patients with triple-negative breast cancer who had received neoadjuvant chemotherapy, with or without immunotherapy, followed by adjuvant radiotherapy. Thirty received radiotherapy with concurrent immunotherapy (five pembrolizumab, 22 tislelizumab, one camrelizumab and two toripalimab) and 102 radiotherapy alone. Radiotherapy parameters and contrast-enhanced CT scans every three months for one year were reviewed.
Main results
Pathological complete response after neoadjuvant therapy was higher in those who later received concurrent immunotherapy (46.7% versus 22.5%; p=0.01). Grade 1 radiation pneumonitis occurred in 63.3% (19 of 30) of the immunotherapy group and 46.1% (47 of 102) of the radiotherapy-alone group, with no statistically significant difference, and there were no grade 2 or higher cases. Hypothyroidism was more frequent with immunotherapy: 33.3% (10 of 30) versus 11.8% (12 of 102); p=0.01, probably attributable to immune-related adverse events. Radiation dermatitis was similar: grade 1 in 10.0% and 9.8%, and grade 2 in 90.0% and 90.2%.
What it means
The authors conclude that adding concurrent immunotherapy to postoperative radiotherapy did not significantly increase radiation dermatitis. There was no statistically significant increase in pneumonitis, but a clinically relevant trend towards more grade 1 cases cannot be excluded. The excess of hypothyroidism calls for monitoring of thyroid function. These are preliminary findings that need prospective confirmation; the retrospective design cannot rule out that the better pathological response reflects differences in patient selection.
Reading from the breast unit
For a breast unit the message is about coordination: if immunotherapy continues during radiotherapy, medical oncology and radiation oncology should share the schedule and follow-up, with attention to thyroid function and respiratory symptoms during the first year.
Reference: Liang G, Zhang Q, Yuan M, Yao G, Yuan F. Safety of concurrent immune checkpoint inhibitor therapy during postoperative radiotherapy for triple-negative breast cancer: A preliminary retrospective analysis. Oncol Lett, 2026. https://doi.org/10.3892/ol.2026.15903
