Recurrence patterns-analysis from a South Indian breast cancer patient cohort.

Background: The current study analyzes the pattern of recurrence/relapse in breast cancer patients belonging to different receptor subtypes to help enhance therapeutic and surveillance methods.

Methods: This is an observational prospective study of a cohort of 543 patients from South India. Associations between various factors and their significance in relapse were assessed by odds ratio (OR), Chi-square test, and two-sided P value.

Results: Relapse of cancer in all receptor subtypes was significantly associated with stage III (P = 0.0029). Of the 48 patients who had a relapse of cancer, 42% had relapsed at a distance recurrence (DR), 23% (P = 0.02) had loco/locoregional recurrence (LLR) and the rest had relapsed at distant and loco/locoregional sites. HER2+ (human epidermal growth factor receptor) (83%) and hormone receptor (HR+/HER2-) (77%) patients had higher DR rates with an OR of 2 (95% Confidence Interval, 0.6-6) and 0.47 (95% CI, 0.1-2.1), respectively compared to TNBC (triple-negative breast cancer) patients. TNBCs (80%) had higher LLR rates over HER2+ (50%) and HR+/HER2- (44%) with an OR of 2 (95% CI, 0.6-6) and 2.1 (95% CI, 0.47-9.3), respectively. Bones and lungs in HR+/HER2- patients, liver and lungs for HER2 + patients, and bones in TNBC patients were the preferred sites for metastasis. The number of metastatic sites followed the order, TNBCs > HER2+>HR+/HER2-.

Conclusions: HR+/HER2- and HER+ patients were more associated with DRs and TNBC patients were associated with LLR. TNBC patients recurred at multiple sites compared to the other two subtypes. Overall, there seems to be a trend in the recurrence across receptor subtypes. Understanding this recurrence pattern will help in enhancing therapeutic and surveillance methods.