The Hugh Adam Cancer Epidemiology Unit team (from left): Sally Wood, Dr Brian Cox, Christina Benfell, Namomo Schaaf and Dr Mary Jane Sneyd. Their science is not performed in the lab, but is in the art of turning interview data into information.

Photo: Alan Dove

LIKE DETECTIVES WORKING BACKWARDS FROM A CRIME scene, the researchers at the Hugh Adam Cancer Epidemiology Unit are hunting for clues about the causes of cancer.

“Most cancers grow in a very insidious form without symptoms for many, many years, often decades, prior to presenting with symptoms,” explains unit director Dr Brian Cox.

Because of this, and the fact the disease predominantly leaves no traces of what triggered it, the victims themselves are usually the only line of inquiry. So, rather than chopping up tissue in the lab, the unit’s research team interviews thousands of cancer patients on their lifestyle, living environment and habits before “performing the art of turning data into information”.

In doing so they are breaking new ground by finding or ruling out cancer causes, in the same way researchers decades ago worked backwards from the lung cancer epidemic and found tobacco was the smoking gun in the victims’ pasts.

“The cellular mechanism by which exposure causes a cancer is usually worked out in a laboratory, later,” Cox explains.

Slow and methodical the work may be – several thousand patients plus an equal number of random members of the public are interviewed in each project – but it can also make headlines, as it did several years ago when the unit published findings looking at whether the risk of prostate cancer was increased by vasectomy.

“We did a study of whether vasectomy increased risk of prostate cancer because the prevalence of vasectomy in New Zealand is the highest in the world.

“We try to capitalise on features of New Zealand that enable us to answer specific questions that have arisen in the international literature or that we think of ourselves,” Cox says. Happily, the unit was able more or less to rule out a link between vasectomy and prostate cancer. United States’ news networks picked up the story and family-planning agencies worldwide breathed a sigh of relief.

When Hugh Adam, an accountant at Speight’s Brewery, made a bequest to set up the unit, it was spiralling rates of cancer that sparked his decision. Now the unit is interested in other forms of the disease, including prostate cancer, bowel cancer and breast cancer.

“Wherever there are cells there’s always potential for them to become malignant. Some organs are far more prone to cellular aberration than others,” Cox says.

Why is this?

Nobody knows, so the work must go on.

“Cancer rates and the risk of cancer change over time. One of the tasks we have is to keep an eye on what is happening with various cancer rates. When changes occur, they don’t happen quickly. You sometimes have to look over 30 years to see the changes occurring in the population.”

At the moment the unit is working on three projects.

Prostate cancer survival: Dr Mary Jane Sneyd is leading a follow-up of 3,760 men diagnosed with prostate cancer in 1996 and 1997 to assess the features of prostate cancer that influence survival after diagnosis in New Zealand.
Delay in the diagnosis of cancer in Pacific Islands men: Namomo Schaaf has interviewed Pacific Islands men with cancer throughout New Zealand to assess the degree of delay in presenting to the doctor after symptoms develop, and the delay between presentation and diagnosis.
Follow-up of breast-screening pilot studies conducted in Otago-Southland and the Waikato: the studies’ impact on breast cancer mortality is being assessed.

There is no shortage of avenues of inquiry for the six-person unit, which includes the director, a senior epidemiologist, a junior research fellow, two interviewers and a secretary. Funding is now being sought for studies into bowel cancer, the effect of new technology on cervical screening and the possible effects of low selenium intake on prostate cancer.

In addition, the unit is helping the International Agency for Research on Cancer to prepare a book describing the avoidable causes of cancer worldwide, and collaborating on two international projects and three further national projects. “There’s plenty to be done. What we can do is determined by the funding we receive,” Cox says.

For the past 15 years the unit has had a stable source of funding for two senior positions from the Directors Cancer Research Trust, set up in 1967 and now administered by the Perpetual Trust. Perpetual client relationship manager Kevin O’Sullivan says the trust came about as a collaboration between Perpetual and the School of Medicine’s director of cancer research. Initially intended to fund extra equipment, it has grown to the point where it now holds about $4 million, the earnings from which are diverted to the Hugh Adam unit.

“When I joined Perpetual I can remember a couple of staff would be going to funerals around the city with a little box in which people could put donations for cancer research.” That has continued, although today brochures highlighting the unit’s work have replaced the collection boxes.

“We can see the worthwhile benefit it has for the Medical School and the unit, and it’s something we promote through our clients,” O’Sullivan says.

Cox is grateful for the help. “It’s really important to have these two core academic staff to keep initiatives occurring.”

The upcoming bowel cancer study (fingers crossed on the funding) is the initiative that animates him most at the moment. Again, as in the vasectomy study, New Zealand provides a unique environment for his skilled interviewers and researchers to do their work as this country has the highest rates of bowel cancer in the world.

“Work we did 10 years ago quite clearly suggested the risk of bowel cancer is largely determined before you’re 30 years of age, so we want to try and establish why that should be the case.

“Very few studies have looked at exposure before the age of 30 … so that would be novel and would, we think, make a major contribution to our understanding of bowel cancer.”

In a curious occurrence, the incidence rates of bowel cancer are markedly different depending on when you were born.

“It’s quite clear that people born after about 1943 seem to have half the risk of developing bowel cancer than older generations.

“It’s been a major change in New Zealand. It won’t show up in overall rates until they get older. People born before then have much higher risk.

“It’s intriguing and hasn’t really been reported before. The unit is trying to establish why that might be the case because we think that may well unravel the cause of bowel cancer.” That would be an extremely important outcome and inline with the unit’s aims.

“The whole thrust of our work is to try to establish what can be done before the diagnosis to prevent the cancer or make treatment easier, and therefore improve the quality of life for people.”

Sean Flaherty