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 ... -  《-》

[Risk-adapted postmastectomy radiotherapy based on local-regional recurrence for T1-2N1M0 breast Cancer].

Li M ，Wang SL ，Fang H ，Tang Y ，Chen B ，Qi SN ，Song YW ，Liu YP ，Lu NN ，Li N ，Tang Y ，Ren H ，Jin J ，Li YX ... -  《-》

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 ... -  《-》

The prognostic differences and the effect of postmastectomy radiotherapy between post-chemotherapy ypT1-2ypN1 and de novo pT1-2N1 breast cancer.

The prognosis and the value of postmastectomy radiotherapy (PMRT) between post-chemotherapy ypT1-2ypN1 and de novo pT1-2N1 breast cancer (BC) remain controversial. We aimed to evaluate the prognostic differences and the effect of PMRT between the two patient subsets. Patients diagnosed with pT1-2N1M0 BC were identified between 2010 and 2018. The study endpoints were overall survival (OS), breast cancer-specific survival (BCSS), locoregional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS) and disease-free survival (DFS). The chi-square test, Kaplan-Meier method and Cox regression analysis were used for data analysis. Total number of 2103 pT1-2N1M0 BC patients were included in the study, including 270 post-chemotherapy (97 without PMRT, 173 with PMRT) and 1833 de novo cases (993 without PMRT, 840 with PMRT). No significant differences were found between post-chemotherapy ypT1-2ypN1 and de novo pT1-2N1 BC patients in 5-year OS (p = 0.068), BCSS (p = 0.054), LRFS (p = 0.241), DMFS (p = 0.104) or DFS (p = 0.08). PMRT did not improve any survival outcome in patients receiving neoadjuvant chemotherapy; however, the PMRT group had a better 5-year BCSS (97.0% vs. 95.8%, p = 0.033) in de novo pT1-2N1 BC. Cox multivariate analysis demonstrated that PMRT was a significant independent predictor of BCSS (HR 0.628; 95% CI, 0.403-0.978; p = 0.04) in de novo pT1-2N1 patients. There seemed no survival difference in post-chemotherapy ypT1-2ypN1 and de novo pT1-2N1 BC patients with contemporary systemic therapy. In addition, PMRT might be exempted in patients with post-chemotherapy ypT1-2ypN1 BC, while not in patients with de novo pT1-2N1 BC.

Yang T ，Zhong X ，Wang J ，Xiang Z ，Zeng Y ，Yu S ，Dai Z ，Xu N ，Luo T ，Liu L ... -  《Cancer Medicine》

Practical Model to Optimize the Strategy of Adjuvant Postmastectomy Radiotherapy in T1-2N1 Breast Cancer With Modern Systemic Therapy.

The effect of adjuvant irradiation after mastectomy in early-stage breast cancer patients remains controversial. The present study aims to explore the clinical benefit obtained from adjuvant radiotherapy among post-mastectomy pT1-2N1 breast cancer patients who received adjuvant modern systemic therapy. Medical records of consecutive patients with pT1-2N1 breast cancer who received mastectomy in our institution between January 2009 and December 2016 were retrospectively reviewed. High-risk features consist of patient age, number of positive lymph nodes, T stage, and Ki67 index, which were developed previously at our institution using early-stage breast cancer patients after mastectomy without adjuvant radiotherapy. Differences of survival and local recurrence were compared between no-postmastectomy radiotherapy (PMRT) and PMRT group according to number of risk factors. The time-to-event curves were calculated by the Kaplan-Meier methods and compared by the log-rank test. Propensity score matching (PSM) was performed to reduce the imbalances in patient characteristics. A total of 548 patients were enrolled (no-PMRT: 259 and PMRT: 289). After a median follow-up of 69 months, the 5-year rate of DFS, BCSS, and LRR in the overall cohort was 90.2%, 97.4%, and 3.6%, respectively. PMRT did not significantly improve DFS, BCSS, and LRRFS in the whole cohort. Patients were divided into low-risk (with no or one risk factor) and high-risk (with two or more risk factors) groups. According to the univariable and multivariable analysis, high-risk group (HR = 1.81, 95% CI 1.11-2.98, p = 0.02) was demonstrated as an independent risk factor for DFS. For the high-risk group, PMRT significantly improved DFS from 81.4% to 91.9% and BCSS from 95.5% to 98.6% and decreased the 5-year rate of LRR from 5.6% to 1.4%, respectively (p < 0.01, p = 0.05, and p = 0.06). However, no survival benefit from PMRT was observed in the low-risk group in terms of DFS, BCSS, and LRR (p = 0.45, p = 0.51, and p = 0.99, respectively). In multivariate analysis, PMRT remained an independent prognostic factor for DFS (HR = 0.50, 95% CI 0.24-1.00, p = 0.05) in the high-risk group. After PSM analysis, the survival benefit of PMRT was sustained in high-risk patients. PMRT significantly improved DFS in high-risk pT1-2N1 breast cancer patients, but not in low-risk patients. Independent validation of our scoring system is recommended.

Xu FF ，Cao L ，Xu C ，Cai G ，Wang SB ，Qi WX ，Chen JY ... -  《Frontiers in Oncology》