Evaluation of Ki67 in pathological prognostic staging of breast cancer: a tertiary care center study.

Background: The rising global burden of breast cancer demands early detection and effective treatment, with a focus on prognostic and predictive markers. The eighth edition of the American Joint Committee on Cancer staging manual introduced a new prognostic staging system to increase the predictive power of the existing anatomical staging system of breast cancer. The current study aimed to establish the correlation between Ki67 expression with molecular subtypes and with the pathological prognostic stage of invasive ductal carcinoma.

Materials and methods: A total of 40 patients were included in the study with samples from 32 modified radical mastectomies and 8 biopsies. Hematoxylin and Eosin staining, histopathological analysis and Ki67 immunostaining were conducted. Descriptive and inferential statistical analyses were performed.

Results: Bloom Richardson Grade II was the predominant histological grade. In Grade II cases, 15 of 24 had a Ki67 labeling index of 26-45%, while 6 exceeded 45% (p = 0.001). Pathological prognostic staging reclassified 27 cases, with 24 (75%) downstaged, 3 (9.38%) upstaged, and 5 (15.63%) retaining their clinical stage.

Conclusions: Ki67 immunohistochemistry is an effective tool for assessing proliferative activity of invasive ductal carcinoma, aiding in pathological prognostic stage stratification and offering insights into tumor biology.