Nat Lawson, whose bowel cancer has spread to other organs, believes regular injections of vitamin C are helping keep the disease under control.

“It’s not getting any worse and I think that’s the vitamin C,” says the 35-year-old Morrinsville married mother of two children aged 5 and 7.

Each injection costs $195 and she has two a week.

Vitamin C treatment for cancer is controversial, and in studies has produced contradictory results. The influential Cochrane Collaboration found no convincing evidence that vitamin C supplements could prevent gastro-intestinal cancers.

But Otago University scientist Professor Margaret Vissers’ work has shown higher levels of vitamin C in bowel and endometrial cancer tissue is associated with extended disease-free survival. She is now investigating the vitamin in breast cancer tissue.

Mrs Lawson’s cancer was diagnosed in March after her bowel had been blocked for two months by the tumour. She saw a GP in January after being constipated for three days.

“Usually I’m fine. I thought it was my diet. I wasn’t tired, there was no blood in my stools, I didn’t have any of the symptoms except not being able to poo.”

The doctor examined her and got her to do a fecal test for cancer – which was difficult because of the blockage – but it was negative. She consulted another GP, who ordered the same test and again it was negative.

In March she experienced a second potential bowel cancer symptom, abdominal pain, and was referred for a colonoscopy, funded by her private health insurance to minimise delay.

Scans followed – one of which cost her $2500 – followed by surgery to hook up a colostomy bag to collect waste, and a port into her chest for the delivery of chemotherapy.

The cancer had spread to the liver, both lungs, the chest and a spot between the spine and an artery.

When asked her prognosis, Mrs Lawson says the cancer specialist “didn’t really say. She says she wants to keep me comfortable now. Everything is working at the moment so we have to stick to it”.

There is no immediate plan for surgery, although the tumours have shrunk, in most cases significantly but less so in the 7cm-diameter bowel tumour.

Mrs Lawson says she didn’t know people as young as her got bowel cancer.

“I didn’t think of it. I haven’t known anyone with bowel cancer. When I went to the doctors they said it’s not hereditary, it won’t be bowel cancer.”