Breast Cancer Trends in Indian Residents and Emigrants Portend an Emerging Epidemic for India

Purpose: As developing nations such as India become increasingly Westernized, incidence rates will increase for many cancers. Presently, breast cancer is the leading cancer site in female residents of India, but rates are considerably lower than in Western countries. Trends observed in Indian immigrants to the West may help predict changes expected in India. Methods: Data were obtained from Indian cancer registries, the SEER program in the USA, IARC scientific database, and published studies. Incidence, age at diagnosis, stage at diagnosis, and hormone receptor status in these three populations were compared for the period 1993-1999. Results: Age-adjusted (to world standard population) incidence rates (per 100,000) in Indian immigrants (47.0-61.0) were higher than in Indian residents (7.2-33.4) but lower than in Western whites (83.1-112.0). Compared to Indian residents, Indian immigrant cases tended to be older (49 years +), diagnosed at an earlier stage, and more often hormone receptor positive, sharing similarities with Western white women. Conclusions: The intermediate breast cancer trends exhibited by Indian immigrants may help predict future incidence trends amongst Indian (particularly urban) residents, which have major public health implications for India as urbanization and Westernization continue. We suggest adding demographic variables to cancer registry data, and additional studies on immigrant Indian populations.