235P - Study on the socioeconomic and clinical factors affecting the proportion of breast conserving surgery in Chinese women breast cancer.

This study intends to investigate the socioeconomic and clinical factors affecting the proportion of breast conserving surgery (BCS) in China. A total of 51237 breast cancer patients were treated in Tianjin Medical University cancer institute &Hospital from January 2005 to January 2018. In order to improve the success rate of BCS, we choose 5660 patients prepared to be treated by BCS to make analysis of independent factors affecting initial positive margins. Finally, we analyzed the survival trend of breast cancer patients after increasing the proportion of BCS by comparing the locoregional free survival (LRRFS), distant metastasis free survival (DMFS), overall survival (OS) of breast cancer patients. Multivariate analysis showed the distance from nipple (P = 0.030), tumor distribution along the duct (OR=2.599,P<0.001), pathological subtype (P < 0.001) and lymph node metastasis (OR = 0.299, P < 0.001), no preoperative MRI examination (OR = 1.291,p=0.001)were independent predictors of positive resection margins. Multivariate analysis revealed that tumor size(OR=0.706,P<0.001), non-mass enhancement (NME)(OR=4.443,P=0.001), malignant enhancement surrounding tumor (OR=1.647, P<0.001) were independent predictors of positive resection margins. The survival analysis of breast cancer patients after increasing the proportion of BCS revealed that the 5-LRRFS of 2005-2010 and 2011-2013 were 97.2%,98.4%, respectively. The 5-DMFS of 2005-2010 and 2011-2013 were 94.1%, 95.2 %, respectively, without significant difference. The OS of 2005-2010 and 2011-2013 were 96.4%, 97.9% respectively. In China,we should gradually reduce the influence of socioeconomic factors on the proportion of breast conserving surgery in the future. Preoperative MRI should be encouraged in patients preparing for BCS. Clinicopathological characteristics and MRI findings are significantly associated with a positive resection margin in breast cancer patients. The author. The National Natural Science Foundation of China (81672623). The author has declared no conflicts of interest. [ABSTRACT FROM AUTHOR]