Abstract P4-06-10: Breast cancer subtypes in Indian women: A comparison of clinicopathological features and outcome

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Abstract Background: Immunohistochemical markers are often used to classify breast cancer into different subtypes that have distinct biological behaviour. The aim of this study was to estimate the distribution of the different subtypes of breast cancer based on immunohistochemistry, in the Indian population and determine their associations with clinicopathological features and outcome. Methods: This is a 5 year retrospective study of 521 breast cancer patients to compare the clinicopathological features and survival of four subgroups – Luminal A (ER/PR +, Her 2 neu –), Luminal B (ER/PR +,Her 2 neu +), Her 2 enriched (ER-/PR -, Her 2 neu +)and triple negative(ER-,PR-,Her 2 neu -). Results: Majority (43.8%) of the patients were in luminal A subgroup. Luminal B patients were 14.8%, Her 2 enriched group were 16.1% and triple negative patients were 25.3%. Median follow up was 34 months. Patients in luminal A subgroup were more likely to be postmenopausal, have smaller size tumours, have grade I/II tumours and have better survival (OS-91.06%), though it was not statistically significantly different from other subgroups. Clinicopathological characteristics and outcome according to breast cancer subtypes Luminal ALuminal BTriple negativeHer 2 neup valueMenopausal statusPre39.09%13.71%30.46%16.75% Post46.60%15.43%22.22%15.74%0.159Type of surgeryBCS44.25%19.54%22.99%13.22% MRM41.78%12.50%27.96%17.76%0.099Type of chemotherapyAnthra based36.68%11.32%29.25%20.75% Taxane + Anthra based36.97%14.29%29.41%19.33%0.923Tumor size in cmsLess than 254.55%12.12%21.21%12.12% 2-546.52%13.52%27.27%12.83% > 528.57%9.52%33.33%28.57%0.065OutcomeAlive without disease44.41%15.59%24.75%15.25% Alive with disease42.67%16.0%25.33%16.0% Death35.56%15.56%26.67%22.22%0.924Grade of tumorI71.43%17.86%3.57%7.14% II51.19%11.95%22.87%13.99% III23.21%16.96%39.29%20.54%<0.001table 1 The triple negative subgroup was more likely to be premenopausal (p value 0.036, odds ratio 0.611, CI 0.394-0.949), have larger and grade III tumours and had worse overall survival (OS-88.46%, odds ratio 1.32, 95%CI 0.602-2.39). Patients in Her 2 enriched group also had the bad prognostic features like larger tumour size, higher grade and worst survival (OS-85.07%, odds ratio 1.78, 95% CI 0.767-4.163).However the outcome was not statistically significantly different for all the subgroups. Conclusions: In this tertiary cancer care hospital retrospective study of breast cancer patients in India, according to the luminal subtypes, luminal A had better prognostic features and survival compared to other subgroups.Incidence of triple negative patients was high, who were mainly premenopausal.Her 2 enriched group had the worst survival among all. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-06-10.