A current review on the epidemiology, genetic susceptibility and molecular profiles of breast cancers in India

Breast cancer (BC) is the most common cancer in India contributing to 14.8% of all cancers in the year 2020. Despite being ~10 years younger on average at diagnosis and increased risk of aggressive hormone receptor negative disease relative to Western patients, no definitive risk factors specific to Indians were previously identified. Herein we highlight the changing incidence patterns, screening strategies and clinico-molecular characteristics of Indian breast cancers that require attention by the scientific community. The National Cancer Registry Programme (NCRP) data showed the highest age-specific incidence in the incidence of breast cancer in northeastern and western regions (Papumare district, Pasighat, Mizoram, Nagpur and Patiala) of India particularly in the age-groups of 40 years and younger. The factors such as younger-age-at-onset, high myeloid cell infiltration, larger tumor size, locoregional spread, lymphovascular involvement and receptor negativity, were reported to correlate with adverse outcomes in Indian patients. The findings from small-scaled pilot studies indicate that the cumulative incidence of pathogenic mutations in non-BRCA genes like TP53, BRIP1, ATM, and PALB2 is ~11-15% in patients with a positive family history of breast or ovarian cancer. The literature evidence pertaining to heritable risk phenotypes and screening strategies discussed in this review should be carefully evaluated for their clinical utility. As increasing amounts of data accumulate, periodic re-evaluation of the evidence is necessary to design effective risk-stratification strategies to address challenges posed by increasing incidence of breast cancer in India.