Melanoma has gone from being Australia's national shame to the poster child of cancer treatment in less than half a decade, as new ways of attacking cancer have been developed.

Four years ago, patients who were diagnosed with stage four melanoma - where the cancer had spread to other parts of the body - were given only six to nine months to live.

You have to smile: Lydia Kassouaa's melanoma has disappeared after she took part in a trial of drugs that target the genetic flaws that cause cancer to grow. Credit:James Alcock

The prognosis for such patients had been stagnant for 40 years while survival rates in almost every other type of cancer improved.

But now more than half the patients trialling a combination of two targeted drugs are still alive two years after beginning the medication, and 12 per cent have moved into complete remission.