Delaying motherhood may protect women against an aggressive form of breast cancer, researchers reveal.
Researchers from Fred Hutchinson Cancer Research Center analyzed the time gap between two factors - menarche (first menstrual bleeding) and time of first birth - and their relationship with triple-negative breast cancer, an aggressive form of cancer.
Breast cancer cells testing negative for estrogen receptors (ER), progesterone receptors (PR) and HER2 are termed as triple-negative breast cancer. It is not caused by hormones estrogen or progesterone. So tamoxifen and Herceptin are less effective in treating this type of cancer. According to BreastCancer.Org., between 10 and 20 percent of all breast cancers are triple-negative.
For the study, Christopher I. Li and colleagues included more than 1,960 women, with (1,021) and without (941) a history of breast cancer. The participants were aged between 20 and 44.
ER-positive (781), triple-negative (180) and HER2- overexpressing (60) were the types of breast cancer involved in the study.
At the end of the study, researchers found waiting at least 15 years to give birth after the first menstrual bleeding cutting down the risk of developing the cancer by 60 percent.
"We found that the interval between menarche and age at first live birth is inversely associated with the risk of triple-negative breast cancer," Li said, in a news release.
However, the researchers emphasize the need to re-confirm their findings.
"This is an observational study and also one of the first to focus on premenopausal breast cancer and so our results require confirmation and thus should be interpreted with some caution," Li said.
Breast cancer is one of the leading causes of cancer deaths among women in the United States. According to a latest estimate from the American Cancer Society, nearly 226,870 women are affected with invasive breast cancer and nearly 39,510 women died from breast cancer this year across the country.
Findings of the study have been published online in Breast Cancer Research and Treatment.
