Significant progress is being made in the prevention and treatment of ovarian and breast cancer, according to findings discussed at a global oncology conference.
“The studies presented at this meeting show impressive progress in disease control and prevention of breast cancer,” said Dr. Andrew Seidman, professor of medicine at Cornell University.
“Also, two consistent studies demonstrated the benefit of adding bevacizumab (Avastin) to standard chemotherapy for ovarian cancer,” he added.
Avastin, produced by Swiss biotech giant Roche, blocks the development of blood vessels needed for tumor growth.
A clinical trial showed a 52 percent reduction in the risk of progression of recurrent ovarian cancer in women who took Avastin in combination with platinum-based chemotherapy.
The most striking finding at the 47th annual meeting of the American Society of Clinical Oncology was that Aromasin, which blocks the production of estrogen, reduced by 65 percent the risk of breast cancer in high risk post-menopausal women.
Close to three-quarters of breast cancer tumors need estrogen to grow.
Breast cancer cell
Annually, there are 1.3 million new cases of breast cancer and nearly 500,000 women die worldwide. In the United States, only lung cancer accounts for more deaths in women.
Paul Goss of Harvard Medical School and lead author of the study on exemestane — sold under the brand name Aromasin — said it’s the “first major clinical trial” in the past 10 years on breast cancer prevention.
“Exemestane may be considered a new option for the prevention of breast cancer,” Goss said during a press conference.
The clinical study was conducted from 2004 to 2010 and enrolled 4,560 women from the United States, Canada, Spain and France who had at least one major risk factor such as being age 60 or older, or having prior breast cancer tumors, including breast cancer with mastectomy.
Half the participants received Aromasin, produced by US pharmaceutical giant Pfizer, and half were given a placebo.
After a period of three years, the Aromasin group had about one third as many invasive cancers as those in the placebo group — a result corresponding to what researchers expected at the beginning of the trial, Goss said.
Aromastate inhibitors like exemestane are distinct from other anti-estrogen therapies such as tamoxifen and raloxifene, which have been approved by the US Food and Drug Administration as preventative therapies for women at high breast cancer risk.
Exemestane, too, has been approved by the FDA, for use in early breast cancer patients.
The most common side effects reported by Aromasin users include fatigue, hot flashes, insomnia and joint pain.
Also Saturday, researchers said extra radiation treatment lowers the rate of breast cancer recurring in women who have had tumors surgically removed.
More than 1,800 women participated, receiving whole breast radiation (WBI) alone or WBI along with radiation to the surrounding lymph nodes.
Five years later, women who received radiation treatment to the breast and lymph nodes had a 41 percent lower rate of recurrences near the tumor site and a 36 percent lower rate of cancer recurrences in other parts of the body.
“These results are potentially practice-changing,” said Timothy Whelan, an oncology professor at McMaster University of Canada and lead author of the clinical study.
Obesity is the biggest driving force behind the most common form of breast cancer in older women, say researchers.
Alcohol and then cigarettes are the next largest culprits, according to Cancer Research UK.
One in eight women in the UK develop breast cancer in their lifetime, data shows, and the majority of these tumours are “hormone sensitive” meaning their growth is fuelled by hormones.
Too much stored fat in the body raises the level of these “sex” hormones.
Studies show that post-menopausal women with high levels of oestrogen and testosterone have between two and three times the risk of breast cancer than women with the lowest levels.
Experts have known for some time that factors that influence hormone levels – like pregnancy, the oral contraceptive pill and the menopause – can change a woman’s breast cancer risk.
This latest work, published in the British Journal of Cancer, suggests obesity should go at the top of this list, not least because it is a lifestyle factor that women can have some control over.
The Oxford University team, funded by Cancer Research UK, studied the health records of nearly 6,300 post-menopausal women, looking for factors that might explain why some developed hormone sensitive breast cancer when others did not.
A woman’s weight had the greatest bearing on a woman’s sex hormone levels, shortly followed by smoking and alcohol consumption.
Women who are overweight or obese – meaning they have a body mass index of 25 or more – had high levels of hormones like oestrogen and progesterone.
So too did women who drank more than two and a half units of alcohol a day or smoked more than 15 cigarettes daily.
Experts say women should be made aware of these modifiable risk factors.
Dr Julie Sharp, of Cancer Research UK, said: “This is an important study as it helps to show how alcohol and weight can influence hormone levels. Understanding their role in breast cancer is vital and this analysis sheds light on how they could affect breast cancer risk.
“We know that the risk of the disease can be affected by family history and getting older, but there are also things women can do help reduce the risk of the disease. Maintaining a healthy body weight and reducing alcohol consumption are key to reducing breast cancer risk.”