A NATURAL hormone considered harmful by some scientists is being tested for potential use in breast cancer treatment.
The University of Liverpool and CRUK Cambridge Institute, in collaboration with the University of Adelaide in South Australia, will conduct clinical trials early next year to test the effectiveness of progesterone in slowing the growth of cancerous tumours.
The trials follow a paper published in Nature by researchers at the University of Adelaide who argued that the controversial method would be safe and ideally suited for therapeutic treatment.
Progesterone is a naturally occurring sex steroid hormone that is being coupled with the breast cancer drug Tamoxifen to attack tumours.
It has been hailed as both controversial and potentially harmful.
The controversy centres on the different effects in women of the naturally occurring sex steroid hormone progesterone compared with synthetic forms (progestins) designed to mimic its actions.
Some, but not all, progestins have been linked with increased breast cancer risk when used in menopausal hormone therapy, leading to concerns in the scientific community about the use of these drugs.
Led by Director of the Dame Roma Mitchell Cancer Research Laboratories at the University of Adelaide, Wayne Tilley, the team have recently published another paper highlighting that progesterone when used in menopausal hormone therapy does not increase breast cancer risk.
“There is no evidence in the literature that progesterone produces risk in laboratory studies or hormone studies,” he said.
“That is why we believe it is a safe agent and when you couple that with the research we published last year, it shows that if you combine progesterone with hormone therapy and oestrogen, you can alter the way a cancer cell grows.
“It makes them (cancer cells) less aggressive, less likely to divide quickly and when you combine it with other drugs, you can, as we’ve showed in pre-clinical models, reduce the growth of breast tumours.”
The team, which is highly regarded for its research into both breast and prostate cancer, believes this new paper will have a global impact on clinical, scientific and public opinion on the relative risks and benefits of using progesterone and certain progestins to treat women with breast cancer.
The first trial with the University of Liverpool will test the potential benefit of combining progesterone treatment with the breast cancer drug Tamoxifen in pre-menopausal women with breast cancer.
The second, initiated by collaborators at the CRUK Cambridge Institute, will evaluate whether a particular progestin, Megace, provides added therapeutic benefit when combined with a current oestrogen receptor target treatment, compared to the target treatment alone.
According to the World Health Organisation, breast cancer is the world’s most prevalent cancer in women with more than 508,000 killed by the disease in 2011.
Professor Tilley said although the trials were being conducted in a pre-treatment space for therapeutic treatment, he was interested in the possibility of whether it could be used in high-risk women as well.
“There is no really good treatment and we are hoping to create a niche for this therapeutic strategy,” he said.
“Sometimes women who responded initially to hormone therapies end up building a resistance to it eventually.
“Hopefully the paper and these trials show people its (progesterone’s) potential and how safe it is.”
The paper titled Deciphering the divergent roles of progestogens in breast cancer was published in Nature Reviews Cancer.
South Australia’s capital Adelaide has three long-standing public universities, Flinders University, University of South Australia and the University of Adelaide, each of which are consistently rated highly in the international higher education rankings.