Chest wall recurrence in pT1-2N0-1 breast cancer patients after mastectomy without radiotherapy.

PURPOSE: In correlation with the nodal status in the era of modern radiotherapy, the chest wall recurrence (CWR) rate was investigated in pT1-2N0-1 breast cancer patients after a mastectomy without post-mastectomy radiotherapy (PMRT). METHODS: The data from the patients participating in two South Korean multi-institutional studies (KROG 14-22; N = 1842 and KROG 14-23; N = 1382) were analyzed. In total, 3224 pT1-2N0-1 breast cancer patients who underwent mastectomy without PMRT were analyzed. RESULTS: The median follow-up time was 72.2 months (range 0.8-125.2 months). The overall CWRs during the follow-up period were 1.68% in N0 patients and 2.82% in N1 patients. There was no statistically significant difference in 5-year and 10-year CWR-free survival (CWRFS) between the N0 and N1 patients. Of the 70 patients with CWR, 33 (1% of all the patients) had isolated CWR, and the 10-year overall survival rate in this group was 96.9%. After the propensity score matching of the N0 and N1 groups, there was still no difference in CWRFS by nodal status. CONCLUSIONS: The incidence of CWR in pT1-2N0-1 breast cancer patients is very low, especially with isolated recurrence. Also, the obtained data showed that the nodal status had no impact on CWRFS.