Application of American Joint Committee on Cancer Eighth Edition Prognostic Stage Groups in Primary Breast Cancer Patients at a Tertiary Care Center in Western Maharashtra

A BSTRACT Introduction: The eighth AJCC prognostic staging system for breast cancer builds upon the anatomic staging by incorporating biomarkers , such as tumor grade and hormone receptor expression, to define clinical and pathologic prognostic stage groups. Grouping by the prognostic stage groups leads to better prognostic distribution of the group and therapeutic outcomes. This study evaluated the use of prognostic stage groups in primary breast cancer patients by studying the stage changes with respect to the traditional anatomic staging and also the factors responsible for the stage change. Materials and Methods: A total of 147 primary breast cancer (61 core biopsies and 86 modified radical mastectomies) cases were studied and assigned both the anatomic stage and prognostic stage groups using the AJCC eighth edition’s breast cancer staging system. Cohen’s Kappa (κ) coefficient was used to measure the level of agreement between two staging systems. Results: The present study shows discordance of 57.4% for clinical and 60.47% for pathologic prognostic stage groups from their anatomic stage counterparts. Cancer stage alterations are significantly affected by histologic grade and biomarker status; where higher-grade and negative hormone receptor tumors upstaged, while well-differentiated and positive hormone receptor tumors are downstaged when compared with anatomic stage. Conclusion: Only slight/fair agreement between the two staging systems emphasizes the limitations of traditional anatomic staging in capturing the heterogeneity of breast cancer biology. The eighth edition of AJCC staging system for primary breast cancer provides a personalized staging approach helping acquire more relevant prognostic information for better patient outcomes.