Locoal Recurrence Risk And Survival Analysis Of Breast Cancer Patients With T1-2 And One To Three Positive Axillary Lymph Nodes Without Postmastectomy Radiotherapy

Background and objective:Breast cancer is a clinically pathologically characterized heterogeneous disease with distinct morphological and molecular biological properties.Radiotherapy is an important adjuvant treatment for patients with breast cancer.The general consensus is that postmastectomy radiotherapy(PMRT)is indicated for patients with a high risk of recurrence,such as patients whose primary tumors are larger than 5 cm and those with four or more positive axillary lymph nodes(ALNs).However,the use of PMRT in patients with early-stage breast cancer with 1–3 positive ALNs(pT1-2N1M0)is somewhat controversial.At present,studies have shown that postmastectomy radiotherapy can bring significant clinical benefits in patients with high risk of local recurrence of breast cancer.Several retrospective studies have reported relatively low10-year LRR rates of 6-10 % for postmastectomy patients with one to three positive ALNs receiving modern adjuvant systemic therapy without PMRT,and some subgroups of patients may benefit from PMRT.However,two recent important studies have shown that 1-3 patients with positive ALN who received regional lymph node radiotherapy did not show significant survival benefits.The results of EBCTCG meta-analysis showed that even after systemic treatment,PMRT could still reduce local regional recurrence and breast cancer-related death.The current breast Cancer clinical practice guidelines of the National Comprehensive Cancer Network(NCCN)also strongly suggest that PMRT should be considered for patients with early breast Cancer with 1-3 positive ALNs.However,there is no direct evidence to support the application of PMRT in patients with stage T1-2N1.This study was designed to investigate the relationship between molecular subtype,clinicopathological features and locoal recurrence in patients with early-stage breast cancer with 1–3 positive axillary lymph nodes(ALNs)and improve the individualized indications for postmastectomy radiotherapy(PMRT).Methods:Clinical data of 7416 breast cancer patients who visited our hospital and received surgical treatment from 2009 to 2012 were retrospectively analyzed,and 489 eligiblepT1-2N1M0(1-3 ALNs positive)patients who did not receive PMRT were selected according to the inclusion and exclusion criteria.The Kaplan-Meier method was used to calculate local recurrence rate(LRR),disease-free survival rate(DFS)and overall survival rate(OS),and draw survival curve.Pearson chi-square test was used to compare the distributions of baseline characteristics among the four subtypes and the survival rates between groups.A Cox proportional hazards model was used for the univariate and multivariate analysis.Results:The 489 patients with pT1-2N1M0 breast cancer who did not receive PMRT,Luminal A,Luminal B(HER-2 negative)and triple-negative breast cancer(TNBC)were 229 cases,196 cases and 64 cases.The median follow-up time was 75 months(range,5-115 months),there were 52 developed LRR,Luminal A,Luminal B(HER-2negative)and triple-negative breast cancer were 18 cases,21 cases and 13 cases.According to the molecular typing analysis showed that compared to non-triple-negative subtypes,triple-negative subtypes had a higher 5-year LRR(7.4%vs 19.0%,?=0.005),lower 5 years DFS(87.7% vs76.0%,?=0.010)and lower 5 year OS(94.7% vs 83.1%,?=0.001).However,there were no significant differences in5-year LRR,DFS,and OS between Luminal A and Luminal B(HER-2 negative)in the non-triple-negative subtypes(?=0.311,?=0.558,?=0.555).Multivariate analysis showed that age ? 35 years(HR=2.756,?=0.001),pT2 stage(HR=2.033,?=0.021)and triple-negative breast cancer(HR=2.968,?=0.003)were independent prognostic factors for LRR.Conclusion:Molecular subtyping is helpful for individualized evaluation of LRR in pT1-2N1M0 breast cancer with 1-3 positive axillarv lymph nodes.Age ? 35 years,pT2 stage and triple-negative breast cancer were independent adverse prognostic factors of LRR in patients without radiotherapy,so PMRT should be recommended for patients with age ? 35 years,pT2 stage and triple-negative breast cancer to reduce the risk of local recurrence and improve prognosis for individualized and precise treatment.