Colorectal cancer in India: controversies, enigmas and primary prevention

Excerpt

Colorectal cancer (CRC) is the third most common cancer in men (663,000 cases, 10.0% of the total cancers) and the second in women (570,000 cases, 9.4% of the total cases) worldwide [1]. Incidence rates of CRC vary 10-fold in both sexes worldwide, the highest rates being estimated in Australia/New Zealand and Western Europe, the lowest in Africa (except Southern Africa) and South-Central Asia [1]. Within Asia, the incidence rates of CRC vary widely and are uniformly low in all south Asian countries and high in all developed Asian countries (Table 1). The burden of CRC has risen rapidly in some economically developed Asian countries like Japan, South Korea and Singapore [1, 2]. Fortunately, the age adjusted incidence rates of CRC in all the Indian cancer registries are very close to the lowest rates in the world [2]. Hospital based and population based data also show that the incidence rates for rectal cancer is higher than colon cancer in all parts of India [2, 3]. Limited data from the rural population based registries indicate that the incidence rates of colon cancer is very low in the rural settings. However the incidence rates of rectal cancer is disproportionately higher in rural India [2‐4]. The intra country variation of the incidence rates of CRC across India is limited, unlike the striking north south differences in the incidence rates of stomach cancer and gall bladder cancer [3, 4]. Population based time trend studies show a rising trend in the incidence of CRC in India [5]. Worrisome is the finding that the incidence rates of CRC in Indian immigrants to the United Kingdom and USA are much higher, suggesting that life styles and dietary habits are important in the causation of the CRC [6‐8]. This also means that with economic transition from a low income to middle income economy, there will be a big increase in the burden of CRC in India. …