An analysis of invasive micropapillary breast carcinoma based on hormone receptor and epidermal growth receptor 2 status

Background: This research aimed to explore the role of combining hormone receptor (HR) with epidermal growth factor receptor 2 (Her-2) status of invasive micropapillary breast carcinoma (IMPC). Methods 1291 IMPC patients were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database of the US National Cancer Institute. The X 2 test and Fisher’s exact probability test were used to evaluate differences between qualitative variables. Univariate and multivariate Cox proportional hazards regressions were performed to assess the independent prognostic factors on cancer-specific survival (CSS) and overall survival (OS). The nomogram models were made to predict 3-year survival rate of IMPC using R software. Results Among 1291 patients, HR+/Her-2- subtype accounted for 74.7%, while HR-/Her-2+, HR-/Her-2-, HR+/Her-2 + accounted for 4.7%, 4.0% and 15.6% respectively. The X 2 test indicated compared to HR+/Her-2- subgroup, HR-/Her-2- or HR+/Her-2 + subtype IMPC had larger tumor size (T stage) and higher histological grade. Compared to HR+/Her-2- IMPC, HR-/Her-2- and HR+/Her-2 + subtypes were more likely to receive mastectomy than conserving surgery. Furthermore, HR+/Her-2- IMPC had more projections to receive chemotherapy and was less likely to receive radiotherapy compared with HR-/Her-2- subtype. Survival analysis suggested that HR-/Her-2- IMPC had the worst OS and CSS. Conclusion This population-based study provided evidence that HR-/Her-2- IMPC accounted the smallest part of four subtypes, but were more likely to have larger tumor size and more advanced histological grade. Furthermore, HR+/Her-2- IMPC had most unfavorable prognosis among four subtypes.