As high as 70 per cent of cancers in India may be attributable to modifiable risk factors: AIIMS oncologist and Lancet study collaborator flags priorities for prevention

While the rate of cancer occurrence and deaths have been going down globally, in terms of sheer numbers, the cancers will continue to increase, affecting 30.5 million people and killing 18.6 million in 2050, according to the latest Global Burden of Disease estimates. To compare, there were an estimated 18.5 million cases and 10.4 million deaths due to cancers in 2023, according to the data.

The rates of cancer occurrence, on the other hand, dropped from 220.6 per 100,000 population in 1990, to 205.1 in 2023, and will likely drop further to 192.9 in 2025. When it comes to cancer mortality rate, it reduced from 150.7 per 100,000 in 1990, to 114.6 in 2023, and will likely drop to 107.9 in 2025, the data shows. This suggests that the increase in the number of cancer cases and deaths are due to growing and ageing populations.

Why are these numbers important?

Most of these cancer cases and deaths will be in the low and middle income countries as per the study. It says over half of the new cancer cases and two-thirds of the cancer deaths will be in these countries, which include India. The global decline in cancer incidence and mortality rate was largely driven by high and upper middle income countries, the study says.

Dr Abhishek Shankar, oncologist from the AIIMS-Delhi and one of the collaborators for the study, said, “We need to work on several fronts, and now. First, there is a need for sustained communication campaigns so that people do not believe in myths and seek care early. These campaigns have to happen year-round and not just on cancer day or no tobacco day. Second, all stakeholders need to be involved. Interventions for cancers have largely been led by oncologists, but that is not enough. Every part of a human body can get a different type of cancer and none of the presentations are consistent. We need to involve everybody for quick detection and treatment of cancers. Unfortunately, one of the biggest health programmes of the country for non-communicable diseases focusses largely on screening and not on diagnosis and treatment,” he said.

“Screening for cancers also has to be evidence based — using methods and in populations where it will result in maximum mortality benefit. And, importantly, any programme on cancer has to adapt quickly to newer therapies as cancer care is evolving at a rapid pace.”

How were the numbers arrived at?

India reported 15.6 lakh cancer cases and 8.74 lakh deaths in 2024, according to estimates based on data from 43 cancer registries across the country. There were an estimated 14.1 lakh cases and 9.16 lakh deaths in 2022, according to estimates from WHO’s Global Cancer Observatory. Both these studies — as well as the present Global Burden of Disease estimates — all depend on data from the same ICMR coordinated cancer registries. They, however, use different models to arrive at the estimates.

The silver lining

The study estimates that around 42 per cent of cancer deaths were attributable to modifiable risk factors such as use of tobacco and alcohol, unhealthy diets, poor control of hypertension and diabetes among others. This means that a significant number of the cancer cases and deaths can be prevented through behaviour change.

This window is larger for India. Dr Shankar says that as high as 70 per cent of cancers in India may be attributable to these modifiable risk factors. “In addition to high prevalence of obesity and diabetes — which are known risk factors for cancers — India also has a large pool of tobacco users including chewing tobacco. We have a high incidence of infections that are associated with cancers such as HPV, Hepatitis B, and H Pylori. The high pollution levels are an additional risk factor for Indians,” he said.

Working towards improved control of chronic diseases, improvement of air quality, cleanliness to prevent infections, vaccination drives for HPV and Hepatitis B can all help reduce cancer burden in the country.