In April 2013, Mr Hill, a grandfather from Masterton, had surgery to remove a lump causing severe pain in his chest wall.
It was diagnosed as a secondary melanoma tumour, although no primary was found. By the following October it had grown back to the size of an apple.
A surgeon judged the disease incurable, but Mr Hill's family doctor suggested he look into a trial of the melanoma drug pembrolizumab, made by Merck Sharp and Dohme (MSD).
He was accepted into the study, making him one of more than 20 patients in New Zealand to receive the drug through international clinical trials.
After some preliminary treatment, he began receiving three-weekly infusions of the medicine at Wellington Hospital last January. CT scans soon found the tumours were shrinking and eventually they disappeared.
"Around the 17th of September I went in and it showed I was completely clear. There were no cancer lesions on my lungs, my liver and nothing on my chest wall. All gone."
He had two more infusions, continues to have CT scans and is still clear of cancer.
Mr Hill accepts he is well short of the standard five-year cancer "cure" mark, but said: "One thing I do know: I'm alive and healthy today and I would like to think I was given an extension. I still feel the same as I did at 45 or 50 and I have got a lot of things I would like to do.
Pembrolizumab has shown such promise that the United States Food and Drug Administration last year gave it fast-track approval as a "breakthrough therapy".
MSD expects to seek regulatory approval in New Zealand this year, followed by an application to Pharmac for state funding, although the agency last year declined a request to fund ipilimumab, an earlier immunotherapy for advanced melanoma, partly because of the cost.
A study published in the medical journal The Lancet found an overall response rate of 26 per cent to pembrolizumab among 173 patients with advanced melanoma. In the US, the drug costs about US$150,000 ($199,788) per patient.