An Australian-led study has unlocked the genetic secrets that allow ovarian cancer cells to resist conventional chemotherapy, clearing the way for better targeted treatments.

After a series of unsuccessful chemotherapy treatments, ovarian cancer patient Rosemary Goulding is concentrating on living life to the full.

The 65-year-old is welcoming groundbreaking new research that could lead to improved therapies for what's one of the hardest cancers to diagnose and treat.

"I was thrilled. It brought tears to my eyes to see that this is happening. I have two daughters and I have five grand-daughters."

The study has identified two major ways the body can reject chemotherapy drugs.

It found some patients have cancerous cells which actually pump the chemotherapy drugs out.

In other patients their DNA prevents the chemotherapy drugs from working.

Leader of the study, Professor David Bowtell from Melbourne's Peter MacCallum Cancer Centre, said until now, medical researchers haven't been able to work out how chemotherapy resistance has emerged in patients.

"This is the best shot that we have had in decades. Now that we have started to map these mechanism, when the cancer comes back we can develop tests that will predict whether a woman is likely to respond to a particular treatment or not."

It's hoped a key outcome of the largest DNA analysis ever conducted will be to improve the disease's survival rate, which has remained stubbornly low for women over the past 30 years compared with other cancers.

Ovarian Cancer Australia's Karen Livingstone said the findings are a game-changer for women.

"To be able to actually identify and individually target the treatment options means that there really will be better outcomes for women and that's what we really need."

Every year, 1400 women are diagnosed in Australia. A thousand won't survive.

But Rosemary Goulding doesn't feel burdened by statistics.

"God has my days numbered and only he can tell me when my day is up. I have days when I don't feel so good, I days when I feel wonderful but I always put my shoes on and go for a walk...every day."