Obesity, poor diet, and physical inactivity are driving the onset of several cancers including gallbladder, colon, kidney, and pancreas, according to a top health expert from the University of Sydney, Australia on 4 May.

Once known to affect the elderly, the last three decades have seen an enormous surge in early onset of cancer, occurring even before people turning 40 or 50.

Various studies have provided evidence that the cancer surge seen globally, including in India, is driven by an unhealthy lifestyle, including high consumption of junk food rich in sugar, salt, and fat combined with a lack of exercise, among others.

"Globally there has been a significant rise in some types of cancer in younger people. For instance, in the 30- to 39-year-old age group in the period 1991 to 2021, the rate of cancers of the gallbladder has increased by 200 per cent, uterine by 158 per cent, colorectal by 153 per cent, kidney by 89 per cent, and pancreas by 83 per cent," said Robyn Ward, Executive Dean and Pro Vice-Chancellor Medicine and Health at the University of Sydney.

"The reasons proposed for this increase include obesity, poor diet, and physical inactivity," she added, noting that "young millennial adults are three times more likely to get cancer than the same age group born in the 1940s".

Who is more at risk?

Robyn noted that "overall, the incidence is higher in men than women and men are more likely to die".

Cancer incidence does vary by organ type, for example, prostate, lung, and colorectal cancer occur the most in males, while breast, lung, and colorectal cancer are predominant in females, the Professor noted.

What are the commonly occurring 'early' cancers? How to prevent it?

In the majority of cancers like cervical, and colorectal, the chance of cure increases with early detection. But for some like brain cancer, early detection makes no difference.

The best proof of prevention is cervical cancer and colorectal (bowel) cancer, said Robyn.

Cervical cancer is preventable through vaccination and treatable if detected early. Infection with specific strains of human papillomavirus (HPV) is the primary driver (95 per cent) of cervical cancer, which is preventable by vaccination.

On the other hand, increasing national screening programmes for breast, cervical, and colorectal (colon) cancers can help boost treatment as well as a decline in mortality rates.

"For the right cancers, early screening will assist, for example cervical, bowel, and breast. But the current screening programmes for these population-based programmes are based on age, not risk," said the professor.

Some younger people may be at higher risk of cancer while elderly may not. So age-based screening programs may not help, but modern technologies like genomics, big data, and artificial intelligence (AI) may play an important role.

"A huge opportunity with modern technologies like genomics, big data, and AI is to develop genetic stratification, incorporated with health records to develop risk-based screening. This helps create personalised screening programmes," she said.