(RxWiki News) The hormone estrogen is well-known for driving breast cancer. Researchers are now finding that estrogen-blocking medications, which are commonly used to help prevent a recurrence of the disease, may have uses in other cancers as well.
A preclinical study demonstrated that a combination of anti-estrogen medications reduced the number of tumors caused by tobacco carcinogens (cancer causing agents) in mice.
This could mean these drugs may be used to prevent lung cancer in former smokers.
"Quitting smoking is still the best way to prevent lung cancer."
Jill M. Siegfried, Ph.D., professor of pharmacology and chemical biology at the University of Pittsburgh Cancer Institute, and colleagues conducted the study.
Estrogen receptors are present in most lung cancers. This makes the tumors grow when they're exposed to estrogen. Additionally, a lung enzyme called aromatase produces estrogen.
These facts inspired Siegfried and her team to investigate if blocking both the estrogen and the aromatase enzyme could prevent lung tumors.
Researchers worked with two groups of female mice - one which was being exposed to tobacco carcinogens, while the other had been exposed previously and had developed precancerous cells.
The animals were treated with one of the following:
- a placebo (sugar pill)
- Arimidex (anastrozole), an aromatase inhibitor (AI)
- Faslodex (fulvestrant), an anti-estrogen
- Combination of Arimidex and Faslodex
In the study, researchers were looking at two models: 1) whether treatments could prevent cancer from developing, and 2) if the treatments could keep precancerous cells from becoming full-blown tumors.
In the first model, the combination therapy given to mice being exposed to tobacco carcinogens resulted in significantly fewer tumors, compared to the placebo or either drug alone. This combination therapy also inhibited tumor development in the second model where precancerous cells had already formed.
This study suggests that anti-estrogen treatment along with an aromatase inhibitor could prevent lung cancer from developing both during tobacco carcinogen exposure and after damage has already happened.
"This is very interesting data, and suggests that anti-estrogens could be an effective therapy in NSCLC [non-small cell lung cancer]," said Adam Brufsky, M.D., Ph.D., professor of medicine at the University of Pittsburgh School of Medicine. "There are currently several phase II trials of fulvestrant and anastrozole open, which are testing this concept in stage IV NSCLC," Dr. Brufsky wrote in an email to dailyRx.
"We may be able to prevent lung cancer in people who have been previously exposed to tobacco carcinogens using some of the same anti-estrogen drugs that can prevent breast cancer," Siegfried said in a news release summarizing the findings.
"A lot of work needs to be done to determine who would benefit from this therapy, and these drugs would need to be tested in clinical trials in those at high risk for lung cancer."
Findings from this research were presented at the AACR-IASLC Joint Conference on Molecular Origins of Lung Cancer: Biology, Therapy and Personalized Medicine, held Jan. 8-11, 2012.