Prognostic Significance of Tumor Budding in Invasive Ductal Carcinoma of the Breast with Neuroendocrine Differentiation

Introduction Invasive ductal carcinoma (IDC) with neuroendocrine differentiation (NED) is a rare subgroup of breast cancer that is treated the same way as invasive ductal carcinoma-no special type (IDC-NST). In this study, we aimed to study the effects of tumor budding on clinicopathological outcomes and survival. Methods Fifty-seven patients previously diagnosed with breast cancer were included in this analysis. Patients were grouped into IDC-NST and IDC with NED using the neuroendocrine markers chromogranin A and synaptophysin. Histological features were re-evaluated by two different pathologists in terms of tumor budding characteristics. Results Patients diagnosed with IDC with NED tended to be older (62.9 ± 15.4 vs 51.7 ± 9.9; P = 0.02). Compared to IDC-NST, IDC with NED group tended to display type A and B mammographic breast composition (P = 0.018), have higher tumor budding (2.7 vs 2, P = 0.009), larger in diameter (3.9 ± 2.3 cm vs 2.5 ± 1.5 cm; P = 0.015), and show higher lymphatic invasion (P = 0.017), vascular invasion (P = 0.042), and perineural invasion (P = 0.045). However, no differences were found in the 5-year overall survival and disease-free survival between the two groups. Conclusion Compared to IDC-NST, IDC with NED exhibited higher levels of tumor budding, were typically larger, and displayed higher lymphatic invasion, vascular invasion, and perineural invasion.