Comparison of 7th and 8th American Joint Committee on Cancer Tumor-Node-Metastasis staging in infiltrating ductal carcinoma of the breast: A retrospective study

Context: The American Joint Committee on Cancer (AJCC) staging system is a very important prognostic factor for treating patients with carcinoma breast. There has been a recent change in the staging of breast cancer, from the 7th edition to 8th edition AJCC. Hence, the present study aimed to analyze the stage migration from 7th to 8th edition AJCC staging in infiltrating ductal carcinoma (IDC) and comparison of each staging system with the Nottingham prognostic index (NPI) prognostic scoring system. Aims: The aim is to evaluate the stage migration between the 7th and 8th edition AJCC in IDC of the breast and compare both staging systems with the NPI prognostic scoring system. Settings and Design: In this retrospective study, we collected the clinical and pathological data from 56 IDC cases from January 2019 to June 2021 presenting at our institute. We restaged all the cases as per the prognostic staging system (8th AJCC) and calculated the survival status with NPI as long-term (5-year survival status) follow-up of the cases was not possible. Statistics: Categorical data were represented in the form of frequencies and proportions. Chi-square test or Fischer's exact test (for 2 × 2 tables only) was used as a test of significance for qualitative data. Continuous data were represented as mean and standard deviation. P value was calculated. Results: In this study, majority of the cases were in grade 1 and in Stage II. Among 16 cases in Stage II A, 7 (43.8%) showed down staging and 3 (18.8%) showed up staging, while 12 (70.6%)/17 cases in Stage II B showed down staging. When compared with NPI both 6th and 7th AJCC showed statistical significance. Conclusion: Stage migration (upstaging and down staging) was seen in the 8th edition AJCC when compared to the 7th edition AJCC. Both the staging system correlated with the NPI prognostic index. However, long-term follow-up of these patients must be done to look into the efficacy of the 8th AJCC staging system before changing the treatment protocol.