A blend of inexpensive drugs is showing promise as a possibly revolutionary treatment for advanced cancers.
Wellington-based researchers are convinced drugs conventionally used to treat conditions such as high-blood pressure and diabetes may halt the growth of cancer cells.
If proven, the proposed treatment could vastly improve a patients chance of survival, and spell an end to chemotherapy, radiotherapy and surgery for some cancers.
Gillies McIndoe Research Institute (GMRI) director Dr Swee Tan, who is speaking about the treatment at a Boulcott Hospital and Hutt Valley Chamber of Commerce breakfast session, said the potential treatment relies on a radical shift in understanding the disease.
"The concept for cancer treatment may be to control the cancer, so that it's more like a chronic condition rather than having to go through that pretty invasive, intensive treatment."
A GMRI trial on 25 patients with glioblastoma, the most aggressive brain cancer, is under way and two patients have already been recruited.
Also approved by the Health and Disability Ethics Committee are trials for malignant melanoma, mouth cancer and metastatic head and neck squamous skin cancer.
It will likely take a year to finish recruiting patients with glioblastoma, Dr Tan said. It will be up to two years before they have preliminary data.
If successful, it could transform the 5 per cent survival rate that comes with the disease, and replace the multiple bouts of surgery, chemotherapy and radiotherapy required to treat it, at about $60,000 per patient each year.
The cocktail of drugs is estimated to cost $4000 per patient each year, and can be taken orally at home.
Dr Tan's confidence in the prospective treatment lies with its origins: GMRI's 2009 discovery that stem cells were responsible for strawberry birthmarks - a vascular tumour.
The research identified the renin-angiotensin hormone system as responsible for controlling the stem cells in the vascular tumour.
Beta-blockers, normally used to lower blood pressure, were found to be effective in altering the hormone system and eliminating the tumour after a 12-month course.
Dr Tan now thinks the same underlying principle applies to 15 types of cancer where stem cells have been linked to the hormone system.
"We're postulating that these cells are the origin of cancer. If they are, then we should be targeting at the root of cancer.
"This being so, we might be able to manipulate this system to control the cancer stem cells."
Fundamental to this a different understanding of cancer, generally considered a cumulation of genetic mutations.
An example: consider a tumour to be a beehive, humming with cancer cells. The majority of cells are equivalent to the humble worker bee; the stem cells are equivalent to a queen bee. If you can stall, block or eliminate the queen bees, you might control the progress of a cancer. "The queen bee is the reason why there's a beehive, because it gives rise to worker bees - cancer cells - and can make other queen bees, and set-up other hives. And this might explain why cancer recurs locally, or at distant sites," he said. There's indirect evidence which indicates this is possible.
A number of studies show that various inhibitors, beta-blockers, and Aspirin can improve the chance of survival by up to 20 per cent for cancer patients, he said.
"The reason why we're doing this is we believe it does work, but we have to prove it."