Association between Molecular subtypes and prognostic factors of breast cancer with a special reference to surgical margin status: A hospital based analysis from Assam, India

Introduction: Breast cancer (BC) is common in young women in India, with 68.8% of cases occurring under 50 years. Key factors regularly evaluated to predict the prognosis and treatment response include tumor size, lymph node, ER, PR, HER2 status, tumor grade, and age. The molecular subtypes Luminal A, Luminal B, HER2- over expression and triple negative breast cancers carry different treatment plan and prognosis Regardless of surgical strategy, margin status of the resection specimen remains one of the most important factors of recurrence. Objective : In a background of higher TNBC subtype, younger age, poorer 5 year survival of BC in women from the region, we studied association between molecular subtypes and surgical margin status as well as other prognostic parameters from a Hospital of North Eastern India. Methodology : It was a cross-sectional study where confirmed BC cases underwent lumpectomy and Modified Radical Mastectomy was included. Tumors were classified into molecular subtypes by immunohistochemistry and other prognostic parameters with surgical margin status were analysed and correlated by Pearson’s Chi-square test and Fisher’s exact test. Results : Total 155 cases, mean age 47 years, histologic Grade III tumors 58.70%, Grade II 36.77% and Grade I -3.87%. The tumor size T1 -5%, T2–57%, T3 -21% and T4 -17%. Lymph node involvement was 77%. Stage 1 and Stage 4 both account for 9.68% each, while Stage 2 has 41.29%, and Stage 3 was 39.35%.TNBC − 36.77%-, Luminal A -29.67%, Luminal B -18.06% and HER2-enriched 15%. Grade III tumors were more common in younger patients. Histologic type, Her2 enriched subtype and grade 3 were associated with positive margin and statistically significant. Conclusion : Positive tumour margin was a risk factor 2 out of 5 BC in women and was more commonly seen in HER2 enriched subtype. One out of 3 women of BC likely to be TNBC type and associated with poor prognostic parameters and shorter survival.