Clinical features and risk factors for recurrence in mucinous breast cancer

Objective To investigate the clinicopathological characteristic and risk factors for recurrence in different subtypes of mucinous breast cancer(MBC). Methods Clinical data of 97 MBC patients at Zhejiang Cancer Hospital from August 2005 to November 2012 were retrospectively analyzed. All of patients were divided into 3 subtypes according to the mucinous components in the tumors, named as partial mixed MBC with less than 50% of mucinous components, main mixed MBC where the mucinous component accounted for 50% to 90%, and pure MBC with more than 90% of mucinous components. In this study, 43, 16 and 38 patients were included in partial mixed MBC, main mixed MBC, and pure MBC, respectively. Follow-up was collected by out-patient, in-patient system and phone call. The relationship between different subtypes and clinicopathological significance were analyzed by χ2 test. Kaplan-Meier curve combined with Log-rank test was used to evaluate the risk factors of relapse free survival(RFS) at 3- and 5-year. Cox proportional hazard regression model was used for multivariate analysis. Results The median follow-up time was 65 months (range 24-125). Of the 97 patients, 14 patients were relapse or metastasis at the end point. The 3- and 5-year RFS were 90.7% and 85.7%, respectively. Tumor size, number of involved lymph nodes (LN), axillary LN metastasis, TNM stages and p53 mutant status were all related with subtypes of MBC(all of P 0.05). Univariate analysis showed menstruation status and TNM stages were associated with the relapse of breast cancer(P<0.05). The patients with menopause and stage Ⅲ-Ⅳ showed significantly shorter RFS time(both of P<0.05). Multivariate Cox proportional hazard regression analysis revealed that tumor size, PR status and postoperative radiotherapy were the independent prognostic factors for the relapse of MBC. Conclusions Tumor size, status of axillary LN metastasis, TNM stages, and p53 mutation status are differ among different subtypes of MBC. The tumor size (>30 mm), PR status and postoperative radiotherapy are the independent risk factors for recurrence, whereas the proportion of the mucinous component is not associated with relapse in MBC patients. Key words: Breast neoplasms; Adenocarcinoma, mucinous; Recurrence; Prognosis