NEW cancer drugs which shrink tumours have been hailed as a "game changer" in the fight against the deadly disease.
The two drugs have been particularly effective in treating skin cancer, which kills an average of two Irish people every week.
An international trial on 945 patients - including Irish sufferers - found treatment with ipilimumab and nivolumab stopped cancer advancing for nearly a year in 58pc of cases.
Cancer specialist Professor John Crown has warned of a "melanoma emergency" in Ireland, with a tripling of the incidence of the disease in the past 15 years.
But he confirmed the results of these drug trials in treating secondary malignant melanoma are "dramatic".
There is also hope these "immunotherapies'' will provide a breakthrough in the treatment of various other forms of the disease including lung, bowel, ovarian and womb cancers.
Professor Crown said while more than 50pc of patients had major tumour shrinkage, approximately 20pc had "complete disappearance".
"Most oncologists believe that a new era of immune system-based treatments has been initiated," he said.
But eminent oncologist Professor Karol Sikora, the dean of the University of Buckingham's medical school, cautioned against expectations of "miraculous breakthroughs" from the latest discoveries.
Prof Sikora told the BBC Radio 4 Today programme: "The immune system has been known to affect certain cancers when stimulated for the last 100 years, but we haven't quite got round it yet.
"The current discoveries being released in Chicago, the media pick them up and for cancer patients it's very sad. You would think cancer was being cured tomorrow. It's not the case. We've got a lot to learn.
"The prolongation of survival from these very expensive immune therapies is often a matter of weeks or months and we've got to make it long-lasting and that has to be our priority.
"I'm afraid it's mixed news. There are breakthroughs coming, there is hope for cancer, that we will do much better in the future.
"It's slow progress, rather than miraculous breakthroughs, as it's likely to be reported."
Meanwhile, the US government is launching a very different kind of cancer study that will assign patients drugs based on what genes drive their tumours rather than the type.
The National Cancer Institute's NCI-MATCH trial will be a massive precision medicine experiment at more than 2,400 sites around the US.
Starting in July, about 3,000 patients will have their tumour genes sequenced to see what mutations or pathways fuel their disease.
About 1,000 patients whose tumor characteristics most closely match one of the 20 or so gene-targeting drugs offered in the study will be put into groups of about 30 patients to get that drug.