Letrozole, a hormone therapy already used with success in the treatment of breast cancer, can extend life in ovarian cancer patients, providing an alternative to chemotherapy, finds a news study published in Clinical Cancer Research.
Letrozole hormone therapy attacks cancer by turning off its estrogen supply. But scientists now believe that in cases of ovarian cancer that are highly sensitive to estrogen, this blocking mechanism slows the growth and spread of disease.
The study, from researchers at the University of Edinburgh, involved 44 women with high estrogen receptor (ER) levels, whose cancer had relapsed after surgery and chemotherapy. They were given 2.5 mg of letrozole daily.
Scientists used a blood-borne tumour marker, CA-125, to track the progress of tumours during hormone treatment.
They discovered that 26 per cent of the women showed no tumour growth after six months of anti-estrogen therapy. And 33 per cent of the group with the greatest ER values showed a positive response which delayed the use of chemotherapy.
The researchers say the therapy can prolong the life of some patients by up to three years, and delay the use of chemotherapy in others.
It is estimated that 2,400 new cases of ovarian cancer will be diagnosed in Canada in 2007. As well, 1,700 women will die of the disease in this country in 2007.
Current treatment involves surgery and chemotherapy, but most ovarian cancers return within two years. Further treatment options have been limited to a second course of chemotherapy. It is hoped hormone treatment could offer life-extension with negligible side effects.
"This is an important landmark in the research and treatment of ovarian cancer," said John F. Smyth, professor of Medical Oncology at the University of Edinburgh, who led the research.
"Despite intense scientific research over the past 20 years, there have been few new leads in our understanding of how this disease operates. But this study suggests that the addition of hormone therapy to our treatment strategy could extend and improve the lives of women with cancer."
