Impact of clinical-pathological factors on locoregional recurrence in mastectomy patients with T1-2N1 breast cancer: who can omit adjuvant radiotherapy?

Postmastectomy radiation therapy (PMRT) in T1-T2 tumors with 1-3 positive axillary lymph nodes (ALNs) is controversial. This study was to identify prognostic factors of locoregional control (LRC) following mastectomy with or without PMRT for patients with T1-2N1 breast cancer and to discuss the selection of patients who might omit PMRT. Between January 2006 and December 2012, the data of 1474 postmastectomy patients staged pT1-2N1 were analyzed. PMRT was applied in 663 patients. LRC and disease-free survival (DFS) were calculated using the Kaplan-Meier method. Cox regression model was applied in the univariate and multivariate analyses to recognize the recurrence risk factors. With the median follow-up duration of 93 months (range, 5-168 months), 78 patients (5.3%) failed to secure LRC and 220 patients (14.9%) experienced any recurrence. The 7.7-year LRC and DFS was 94.9% and 85.4% respectively in the entire cohort. PMRT significantly improved 7.7-year LRC from 93.4% to 96.6% (p = 0.005), but not the DFS (p = 0.335). Multivariate analysis revealed that PMRT was an independent prognostic factor of LRC (p < 0.001), meanwhile, age ≤ 40 years (p = 0.012), histological grade 3 (p = 0.004), 2-3 positive nodes (p < 0.001) and tumor size of 3-5 cm (p = 0.045) were significantly associated with decreased LRC. The 7.7-year LRC for patients with 0, 1, and 2-4 risk factors was 97.7% / 98.9% (p = 0.233), 95.3% / 98.0% (p = 0.092), and 80.3% / 94.8% (p < 0.001) in the non-PMRT and PMRT group, respectively. In patients with T1-2N1 breast cancer, clinical-pathological factors including young age, histological grade 3, 2-3 positive nodes, and tumor size of 3-5 cm were identified to be predictors of a poorer LRC following mastectomy. Patients with 0-1 risk factor might consider the omission of PMRT.

Wang X ，Zhang L ，Zhang X ，Luo J ，Wang X ，Chen X ，Yang Z ，Mei X ，Yu X ，Zhang Z ，Guo X ，Shao Z ，Ma J ... -  《-》

Postmastectomy radiotherapy in patients with T(1-2)N(1) breast cancer: a single center experience and a meta-analysis.

Postmastectomy radiotherapy (PMRT) in patients with T1-2N1 breast cancer is still controversial. This study was to evaluate the survival prognosis of T1-2N1 patients with or without PMRT. From January 2006 to May 2017, 2606 female breast cancer patients underwent mastectomy in our medical center, among whom 402 patients of T1-2N1 stage with or without PMRT were finally analyzed. The median follow-up duration was 59.5 months. The primary endpoint was overall survival (OS). The secondary endpoint was disease-free survival (DFS). In the study of our center, no statistically significant difference was observed between the T1-2N1 PMRT and non-PMRT subgroups for the 5-year OS (94.4% vs 95.4%, p = 0.667) and DFS (90.1% vs. 91.1%, p = 0.798). By the date of the last follow-up, 8.96% (n = 36) of the patients experienced any recurrence. Univariate analysis revealed that PMRT was not a prognostic factor for either OS (p = 0.667) or DFS (p = 0.798) in T1-2N1 patients. We then did a meta-analysis on the current treatment patterns, in which 2606 PMRT and 4281 non-PMRT T1-2N1 breast cancer patients with mastectomy were included. The meta-analysis showed that PMRT didn't improve the OS of the patients (HR = 0.85, p = 0.11), but patients with PMRT had better DFS than those in the non-PMRT group (HR = 0.62, p < 0.001). PMRT did not affect the survival of T1-2N1 breast cancer patients who underwent mastectomy, suggesting that radiotherapy may be safely omitted for them.

Luo M ，Jin Y ，Xu C ，Chen H ，Zhang K ，Chen Q ，Jin C ，Lu J ，Wang J ，Huang J ，Deng H ，Jin W ，Zheng S ，Chen Y ，Zhou J ... -  《-》

Effectiveness of the AJCC 8th edition staging system for selecting patients with T1-2N1 breast cancer for post-mastectomy radiotherapy: a joint analysis of 1986 patients from two institutions.

Wang S ，Wen G ，Tang Y ，Yang Y ，Jing H ，Wang J ，Zhang J ，Zhao X ，Sun G ，Jin J ，Song Y ，Liu Y ，Fang H ，Zhang Y ，Li Y ... -  《BMC CANCER》

Postmastectomy radiotherapy improves disease-free survival of high risk of locoregional recurrence breast cancer patients with T1-2 and 1 to 3 positive nodes.

He ZY ，Wu SG ，Zhou J ，Li FY ，Lin Q ，Lin HX ，Sun JY ... -  《PLoS One》

Selecting breast cancer patients with T1-T2 tumors and one to three positive axillary nodes at high postmastectomy locoregional recurrence risk for adjuvant radiotherapy.

Truong PT ，Olivotto IA ，Kader HA ，Panades M ，Speers CH ，Berthelet E ... -  《INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS》