Hormone therapy associated with reduced colorectal cancer risk

Jan 08, 2009

The combination of estrogen plus progestin, which women stopped taking in droves following the news that it may increase their risk of breast cancer, may decrease their risk of colorectal cancer, according to a report published in the January issue of Cancer Epidemiology, Biomarkers and Prevention, a journal of the American Association for Cancer Research.

"Compared to women who had never taken these hormones, the use of estrogen plus progestin was associated with a reduced risk of colorectal cancer," said Jill R. Johnson, M.P.H., a doctoral student at the University of Minnesota School of Public Health.

The largest risk reduction, approximately 45 percent, was seen among women who had completed use of estrogen plus progestin five or more years previously.

Johnson and her colleagues extracted data from 56,733 postmenopausal women who participated in the Breast Cancer Detection Demonstration Project follow-up study. Hormone therapy use and other risk factors were ascertained through telephone interviews and mailed questionnaires between 1979 and 1998. During an average 15 years of follow-up, Johnson and colleagues identified 960 new cases of colorectal cancer in this population.

Any use of estrogen therapy was associated with a 17 percent reduced risk in colorectal cancer. Among those who used estrogen, the largest reductions were seen among those who were current users (25 percent reduced risk) and users of ten or more years duration (26 percent reduced risk).

Researchers also found a 22 percent reduced risk among those who had ever used estrogen plus progestin in combination. They further found a 36 percent reduction in risk among those who had used progestin sequentially or less than 15 days per month. Past users of estrogen plus progestin, who had stopped at least five years ago, had a 45 percent risk reduction.

Although Johnson's study was not designed to look at biological mechanisms for the protective effect of estrogen therapy, she did say that previous research has suggested that hormones may play a role in decreasing levels of insulin-like growth factors, thereby reducing risk. "The biological mechanism will need to be explored in further studies," said Johnson.

Source: American Association for Cancer Research

Explore further: Population-based FIT screening can reduce CRC mortality

Related Stories

Salt-tolerant herb rich in antioxidant compounds

May 19, 2015

Epidemiological studies have emphasised the importance of eating foods high in antioxidants to reduce the risk of developing cancer and cardiovascular disease, two leading causes of death worldwide. Inside ...

"Living outside the Earth is a huge challenge"

May 08, 2015

Susana Zanello is an expert of human adaptation to life in space. Invited as an academic guest at EPFL, this renowned scientist agreed to share her views on her research, exploration, future trips to Mars ...

Automated counting of tumor cells in blood

May 04, 2015

Biological and medical scientists have been using flow cytometry to count cancer cells for the past 40 years. But the large instruments are expensive and can only be operated by trained personnel. By contrast ...

Recommended for you

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.