Purpose: There is considerable variation in prevalence rates of triple-negative breast cancer (TNBC) reported by various studies from India. We performed a systematic review and literature-based meta-analysis of these studies.
Methods: We searched databases of Medline, Scopus, EMBASE, and Web of Science for studies that reported on the prevalence of TNBC in India that were published between January 1, 1999, and December 31, 2015. We extracted relevant information from each study by using a standardized form. We pooled study-specific estimates by using random-effects meta-analysis to provide summary estimates. We explored sources of heterogeneity by using subgroup analyses and metaregression.
Results: Data were obtained from 17 studies that involved 7,237 patients with breast cancer. Overall combined prevalence of TNBC was 31% (95% CI, 27% to 35%). There was substantial heterogeneity across the studies (I2 of 91% [95% CI, 88% to 94%]; P < .001) that was not explained by available study level characteristics, including study location, definition of human epidermal growth factor receptor 2 or estrogen receptor, mean age of participants, proportion of patients with premenopausal cancer, grade 3 disease, or tumor size > 5 cm. Overall combined prevalence of hormone receptor-positive and human epidermal growth factor receptor 2-positive breast cancer was 48% (95% CI, 42% to 54%) and 27% (95% CI, 24% to 31%), respectively. There was no evidence of publication bias.
Conclusion: Prevalence of TNBC in India is considerably higher compared with that seen in Western populations. As many as as one in three women with breast cancer could have triple-negative disease. This finding has significant clinical relevance as it may contribute to poor outcomes in patients with breast cancer in India. Additional research is needed to understand the determinants of TNBC in India.