CHENNAI: Over two decades back, doctors at Tata Memorial Hospital, Mumbai, noticed that most gall bladder cancer patients were from the Gangetic belt states of Bihar, Uttar Pradesh or West Bengal. This led to a series of studies that found high concentration of heavy metals in the soil and ground water in this belt — a likely factor for high incidence of gall bladder cancer.
It is now well known that the incidence of gall bladder cancer is highest in the country's eastern side while south India registers the lowest.

Environment and lifestyle are among the leading risks. The incidence of lung cancer is registering a rise in metros, be it Bengaluru or Delhi. Women in urban India are more likely to get breast cancer than those in rural areas.

The Indian government's Million Death Study released in 2012 for the first time showed that that the area an Indian lives in, his economic and educational status and religion contribute to the malady's outcome. A youngster from India's northeast is four times more likely to develop and succumb to cancer than one from Bihar.

"There is growing evidence that environment and lifestyle can cause cancer in younger people as well," said former director-general of ICMR, Dr Vishwa Mohan Katoch. "While some cancers are common, others are specific to a region," he said, adding that in the Gangetic plains the risk of gall bladder cancer is very high due to polluted water, sediments in water and high consumption of animal protein and fish.

Every day, 1,500 people die of cancer in India, making it the second most common cause of death in India after cardiovascular disease. And nearly 2,000 new cancer cases are detected in the country daily, according to National Institute of Cancer Prevention and Research. Projections put the number of new cases by 2020 at 17.3 lakh.

In eastern India, rise in tobacco use has led to an increase in lung cancer among men, and rapid changes in food habits have made women more vulnerable to breast cancer, said Kolkata-based oncologist Gautam Mukhopadhyay.

Common cancers in the north-east are oesophagus, stomach and hypopharynx. Registries in the north-east have also recorded the country's highest incidence of nasopharynx and gall bladder in Nagaland and Kamrup in Assam.

In Bengaluru and Chennai more than a quarter of the total number of cancers in women are of the breast. Bengaluru-based Dr PP Bapsy said mass screening is most important to detect cancer early. "We need low cost, accessible treatment," Dr Bapsy said.

Most oncologists insist that lifestyle changes will by itself bring down incidence. "By some magic, if everyone stopped using tobacco in India, we will have at 50% lesser cancer cases," said Dr Rakesh Jalali, medical director of Apollo Proton Cancer Centre.