The age of a bowel cancer patient could determine what type of treatments they then go through.

The age of bowel cancer patients could help determine the treatment they are given, a study has found.

Bowel cancer has five distinct subtypes that are closely related to a patient's age, according to the QIMR Berghofer Medical Research Institute.

Associate Professor Vicki Whitehall said new ways of classifying bowel cancers may have implications for the kinds of treatments that patients are offered.

About 17,000 Australians are diagnosed with bowel cancer annually, and more than 4000 die according to the Australian Institute of Health and Welfare.

Lead researcher Lochlan Fennell said bowel cancer generally struck later in life.

"Our study indicates that the different genetic changes that cause cancer happen at different ages and that might have implications for different treatments," he said.

"We know some types respond better to immunotherapy and other targeted therapies while other types are resistant to these therapies."

The three-year study involved samples from 216 patients at the Royal Brisbane and Women's Hospital.