Comparison of Clinicopathologic Features and Survival Outcomes of Pleomorphic Lobular, Classical Lobular, and Invasive Ductal Carcinoma.

PURPOSE

The objective of this research is to assess the clinical importance of pleomorphic lobular carcinoma (PLC) by contrasting its survival outcomes and clinicopathological characteristics with those of classical invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC).

METHODS

Data from the SEER (Surveillance, Epidemiology, and End Results) database, which covers patients with breast cancer diagnosed between 2010 and 2021, are used in this retrospective analysis. Clinical, pathological, and demographic factors were noted. Kaplan-Meier and Cox regression models were used to conduct survival analyses.

RESULTS

A total of 639,943 patients were included in the study. 182 (0.03%) patients were diagnosed with PLC, 74,565 (11.6%) were with ILC, and 565,196 (88.3%) were with IDC. Compared with ILC and IDC, PLC was associated with higher tumor grade, higher T, N stage, and stage 3-4 AJCC stage, higher hormone negativity, and triple negativity rates. Breast-conserving surgery (BCS) rates were lower in the PLC group, whereas mastectomy, no surgery, and chemotherapy rates were higher. Five-year and 10-year overall survival (OS) and disease-specific survival (DSS) rates were significantly lower in the PLC group than in both ILC and IDC (p < 0.05). However, when survival outcomes were evaluated according to stage, no statistically significant differences in overall survival (OS) or disease-specific survival (DSS) were found between PLC and ILC or between PLC and IDC across all disease stages (p > 0.05).

CONCLUSION

PLC, a very rare type of breast cancer, has worse clinicopathological features and worse survival outcomes than both ILC and IDC. These findings highlight the need for more specialized personalized targeted therapeutic strategies for PLC.