Effect Of Radiotherapy On The Prognosis Of Patients With Different Molecular Types Of T_1-2N₁ Breast Cancer

Objective:To investigate the prognosis of postoperative radiotherapy for T_1-2N₁breast cancer.Methods:186 cases of T_1-2 breast cancer with 1-3 positive axillary lymph nodes（stage II）who underwent modified radical mastectomy in Xinjiang Medical University affiliated tumor hospital from January 2014 to September 2017 were collected.The pathological diagnosis was invasive ductal carcinoma,and the surgical margin was negative.All patients received postoperative adjuvant chemotherapy.According to whether radiotherapy was performed or not,the patients were divided into radiotherapy group（n=126）and non radiotherapy group（n=60）.The LRR,5-year OS,5-year DM and the impact of related factors on survival and prognosis were analyzed.Results:The 5-year LRR,DM and OS in the radiotherapy group were 0.8%,10.3%and 94.4%,respectively,and the 5-year LRR,DM and OS in the non-radiotherapy group were 15.0%,10.0%and90.0%,respectively.The 5-year LRR in the radiotherapy group was lower than that in the non-radiotherapy group,with a statistically significant difference（P=0.000）,while there was no statistically significant difference between the 5-year DM and OS in the two groups（P=0.266,0.947）.Multivariate analysis of the prognosis of patients:no radiotherapy after surgery was the adverse prognostic factor of 5-year LRR（P=0.004）.Triple negative breast cancer is an independent poor prognostic factor for 5-year OS（P=0.014）.In the non-tri-negative subgroup,the 5-year LRR of the radiotherapy group was 0%,lower than that of the non-radiotherapy group（13.2%）,with a statistically significant difference（P=0.000）.In the three negative subgroups,there was no statistically significant difference between 5-year LRR and 5-year DM（P=0.099,0.908）.Conclusion:Postoperative radiotherapy can significantly reduce the LRR of non triple negative T_1-2breast cancer patients with 1-3 positive axillary lymph nodes（N1）after modified radical surgery,but has no effect on 5-year DM and OS.Postoperative radiotherapy does not seem to improve the prognosis of triple negative breast cancer patients.Non radiation therapy,triple negative breast cancer were the adverse prognostic factors.