Postoperative radiotherapy is a conventional treatment for breast cancer patients with a high risk of recurrence, such as those with regional lymph node metastasis, especially TNBC. However, the optimal mode of treatment for the combination of radiotherapy and immunotherapy has not yet been determined, especially in the adjuvant treatment phase. There is still a lack of validation and high-grade evidence on the safety and synergistic efficacy of radiotherapy-immunotherapy combinations. In this study, we aimed to compare the safety and preliminary efficacy of hypofractionated radiotherapy and concurrent immunotherapy with those of hypofractionated radiotherapy and sequential immunotherapy in the postoperative adjuvant stage through prospective real-world studies for TNBC patients, and focused on verifying the incidence of adverse reactions in radiotherapy and immunotherapy in the adjuvant stage, so as to find out the optimal combination mode of postoperative radiotherapy combined with immunotherapy, further reduce the distant metastasis of TNBC patients under the premise of ensuring safety, and improve long-term survival.

Inclusion Criteria:

1. Age 18-65 years;
2. Triple negative invasive breast cancer, with immunohistochemistry confirming that the primary lesion was ER- or ER<10% and weakly expressed, PR-, HER 2-;
3. Patients who had surgery after neoadjuvant immunotherapy, and required a hypofractionated radiotherapy regimen of whole breast/chest wall ± regional lymph nodes ±tumor bed: whole breast/chest wall ± regional lymph nodes DT 40.05Gy/15F; Sequential dose increase of DT 2.9 Gy*3F for tumor bed in breast conserving patients; For patients with a stage of T4 or N3c, it is up to the radiation oncologist to decide whether to proceed with sequential bolsing of locoregional lesions;
4. Patients received adjuvant immunotherapy after neoadjuvant immunotherapy, and the drugs used for postoperative immune maintenance were the immunodrugs used in the neoadjuvant treatment stage;
5. Patients who have not received neoadjuvant immunotherapy and require 1 year of adjuvant immunotherapy and hypofractionated intensity-modulated radiotherapy for whole breast/chest wall ± regional lymph nodes ± tumor beds in the postoperative adjuvant stage.

Exclusion Criteria:

1. Failure to complete the course of radiotherapy as planned
2. Concomitant contralateral breast cancer or second primary malignancy (except basal cell carcinoma of the skin and carcinoma in situ of the cervix);
3. Previous history of thoracic radiotherapy;
4. Serious heart, lung, liver, kidney, hematopoietic and nervous system diseases, mental diseases;
5. Concomitant autoimmune diseases such as scleroderma or active lupus erythematosus; pregnant and lactating patients;
6. Patients with prior immunotherapy-related grade 3-4 toxicities during the neoadjuvant immunotherapy phase

Tripple negative breast cancer patients who require hypofractionated radiotherapy and immunotherapy