The clinicopathologic characteristics of Invasive Papillary Carcinoma as a rare subtype of invasive breast carcinomas

Background: Invasive Papillary Carcinoma (IPC) of breast is a rare subtype of breast cancers. For years it has been reported as case reports. We have evaluated the clinicopathologic characteristics of Invasive Papillary Carcinoma of breast and its differences with Invasive Ductal Carcinoma (IDC). Material and Methods: Retrospectively, the medical records of 4622 patients were reviewed in the Breast Disease Research Center, Shiraz University of Medical Science, from December 1993 to December 2017. The tumor size, lymph node metastasis, pathologic stage, nuclear and histological grade, hormonal receptor status, recurrence, disease-free, and overall survival were reviewed. Differences between IPC and IDC were analysed statistically using the Chi-square, Fischer, independent-sample t test, and Kaplan- Meier analysis (SPSS version 19.0). P<0.05 were considered statistically significant. Results: The mean age of IPC patients was 57.5 years and the mean age of IDC was 48.9 years (P=0.02). The frequency of HER-2 negative cases was higher in the IPC group compared to the IDC (100% vs. 70.5%, P=0.04). Besides, 83.3% of the patients with IPC and 97.3% of those with IDC received chemotherapy (P=0.03). In local invasion, IPC was less invasive compared to IDC (P=0.001). The disease-free survival (DFS) and overall survival (OS) not differed significantly between the IPC and IDC groups (5-year DFS: 86.5% vs. 90.9%, P=0.81; 5-year OS: 92.9% vs. 95.1%, P=0.67). Conclusion: IPC is a rare tumour type presents with unique clinicopathological characteristics. It occurs in older patients, it is less invasive and has more HER-2 negative cases compared to IDC.