Cancer Shift Worker

Reporter: Andrea Burns

Elouise Constantine has had three bouts of breast cancer in the past five years. When she's well, Elouise is a nurse, working shifts. She believes there may be a link between her illness and her job. "I love my job and all that it entails the fact that we do shift work where there's not big rest periods sometimes between shifts means that you have not as much sleep as probably someone that works 9-5 "

"The body's working against what's natural for it." Associate Professor Lin Fritschi, from the WA Institute for Medical Research is heading a team of researchers who'll gene test three thousand West Australian women, looking for proof of whether shift work has serious medical consequences. "The short term effect of shift work is quite clear, we know people are tired, we know there are increased injury rates, we know they feel bad but the long term effects are not really clear/ There's more and more interest on whether there are long term effects on the cardiovascular system and with cancer as well"

Already, overseas studies in mice have shown a possible link but there's little evidence when it comes to humans. Associate Professor Fritschi says the disruption to what's called the body's "cicadian rhythm" may be at the root of these serious illnesses.


in says "cicadian rhythm is the rhythm that guides our entire body in the day/night cycle. So it tells us it's time to sleep and it's time for all the functions of the body to be shut down and have a rest and it's time to get up and start acting again"

Sleep expert Dr David Hillman explained the physical effects, earlier this year. "Things like cardiovascular disease and certain cancers, now they're just theories that certainly deserve further investigation at the moment"

Here's one theory ...

When light hits your eye ... it travels along your optic nerve ... to a tiny part of your brain called the suprachiasmatic nuclei ... better known, as your biological clock. The light, is like a big alarm telling you, it's time to wake up, even if it's still the middle of the night. The problem is that sets off a chain reaction.

David Hillman says "this little nucleaus sends a signal to another area called the pineal gland and that supresses the production of melatonin" and this is where it gets tricky. When the melatonin tap is turned off ... other taps are kick started to turn on. Including the production of some hormones ... and it's believed THAT can lead to serious diseases. "Amongst the hormones affected are hormones like estrogen and higher levels of estrogen is associated with higher breast cancer rates"

Associate Professor Fritschi says this latest study will approach women aged 18-80, some from the cancer register, who've had the disease and others from the electoral role, who haven't, and compare information about their lifestyles.

Lin says "we'll be sending out a letter, asking them to fill out a questionnaire, and to provide a sample of dna so we can look at the interactions between genes and environment."

"Invariably they ask why, what's caused this, what have I done wrong?" Sherryl Potts, a breast care nurse from the Breast Cancer Foundation says identifying what causes the disease will save lives. "Breast cancer is not one disease only, there are so many factors that influence and it does seem to be such a complex disease any research that's done I would think would be beneficial"

Ironically, Elouise Constantine works on the cancer ward where she was treated. She believes her experience with cancer gives her a greater empathy with her patients. It was a heart breaking way to gain insight."I hope that for people like myself what you feel is going to be evidence based rather than just something we thin contributes to breast cancer it'd be very interesting to see what comes out of the research"

For further details visit

The Breast Cancer Environment and Employment Study website is:

WAIMR website is: