More Australians under the age of 40 are being diagnosed with cancer than at any point on record, with medical experts pointing to a mix of lifestyle, environmental and screening-related factors behind the rise. The trend is particularly concerning because cancers such as bowel and thyroid cancer, once considered diseases of older age, are increasingly being found in younger adults, prompting calls for greater awareness of early symptoms and possible risk factors among this age group.

Doctors cited in the report highlight potential contributors including rising obesity rates, poor diet, sedentary lifestyles, alcohol consumption and environmental exposures, alongside improved detection methods that may be picking up more cases earlier than before. Bowel cancer and thyroid cancer were specifically flagged as showing notable increases among younger Australians, with specialists urging people under 40 not to dismiss persistent symptoms and to seek medical advice promptly rather than assuming they are too young for a cancer diagnosis.