Today marks World Cancer Day, and a University professor said we're on the cusp of a world where a cancer prognosis isn't considered a death sentence.

Otago University's Parry Guilford said a new method of tracking the progression of the disease means it's going to be easier to find the right treatment for tumours.

He said it uses liquid biopsies to track DNA mutations from the tumour as they appear in the bloodstream, finding long-term evidence of any changes or relapse.

"I think we're going to move to a world where cancer is seen as a chronic disease rather than a more fatal disease, a world where a patient is treated with a drug and there's a long period of response to that drug."

Professor Guilford said new research is ready for wider application which will help determine if treatments are working long-term.

"Evidence of any progression or relapse will be followed using these liquid biopsies and then if the disease starts to come back there should be a sign in the blood samples of changes in the DNA which might indicate the next drug to best be used."

Professor Guilford said there are still limited drug treatments, due to the length and complexities of testing and trials.