Can you help make breast cancer history?

Researchers from the International Breast Cancer Intervention Study, known as IBIS-II, are calling on women to participate in a trial that may very well help to prevent breast cancer.

IBIS-II principal investigator UWA Winthrop Professor Christobel Saunders says it is the final callout before recruitment closes in December, in which 8000 women are needed worldwide.

“WA is the third highest recruiter in the world for this study…we’ve had a great response, but we still need more,” Prof Saunders says.

The trial is designed to test the efficacy of the drug anastrozole in preventing the development of breast cancer in women at high risk. It follows on from IBIS-I trial, which tested the use of tamoxifen for the same indication.

Though tamoxifen showed some promise, researchers feel the new suite of aromatase inhibitors (which include the drug anastrozole) may hold a better chance of decreasing risk while exhibiting a better side effect profile.

For example, side effects of tamoxifen include such events as womb cancer and blood clots; while side effects of anastrozole may include hot flushes, vaginal dryness and an increase risk of osteoporosis.

Aromatase inhibitors also work in a very different way than tamoxifen. Tamoxifen works by blocking the cell receptors of oestrogen circulating in the body, whereas; aromatase inhibitors such as anastrozole block the enzyme of aromatase and by doing so, block the initial production of oestrogen.

While oestrogen does not cause cancer, because cancer cells have receptors for oestrogen, the hormone can drive the growth of those cells.

Prof Saunders says scientists still do not know definitively how this process works in a preventative setting but says it may be because, “if there are just one or two cancer cells ‘hanging around’ the drug could block their growth”.

“However, it could be a different mechanism altogether.”

The study came about after anastrozole—when used in direct treatment of breast cancer—seemed to reduce the chance of sufferers developing cancer in the other breast.

“It naturally led us to believe this could be a better drug in chemo-prevention,” Prof Saunders says.

She also says researchers believe the drug may have a preventative effect long after the medication is stopped.

To join the study women must be postmenopausal, aged from 40-70, and have high risk factors such as family history or biopsied benign lesions.

The trial will require participants to take tablet a day for five years and receive a bone health check when they begin the study.

Of the 8000 participants, half will receive the drug and the other half will receive a placebo. The two groups will then be compared.

“It’s heralding in a whole new era in preventing cancer.”

By Laura Glitsos

(Source: Science Network Western Australia)

More information

For more information on breast cancer, types of breast cancer and its investigations and treatments, as well as some useful videos, see Breast Cancer.