A new British study, published in the September online edition of PLoS Medicine, finds strong evidence that women who are longer and heavier at birth are at increased risk of developing breast cancer later in life.
A team of researchers led by Dr. Isabel dos Santos Silva, a professor of epidemiology at the London School of Hygiene and Tropical Medicine, examined the results of 32 studies, both published and unpublished, evaluating more than 22,000 cases of breast cancer among 600,000 women.
They compared breast cancer risk with birth size, relying on birth records, parent recall and self reports.
Researchers found, women heavier and longer at birth had increased risk for breast cancer as an adult. Women who weighed more than 8.8 pounds at birth have a 12 percent increase in breast cancer risk, compared to women who weighed 6.6 to 7.69 pounds at birth.
As for length, women who were 20 inches at birth had a 17 percent increased risk of cancer, compared to women who were 19.29 inches at birth.
Head circumference was also linked to an increased risk of breast cancer. Although, length was the strongest independent predictor of risk compared to head circumference and birth weight, researchers report.
“Identifying early life influences are significant in the etiology of breast cancer and helps to explain why many adult primary prevention practices have been of limited effectiveness,” said Dr. Dimitrios Trichopoulos, the Vincent L. Gregory Professor of Cancer Prevention at Harvard University School of Public Health Department of Epidemiology
Breast cancer prevention needs to take into consideration the long natural history of the disease.
“We aren’t going to advise women to do anything differently than they are doing now. And we are not going to label these women as high risk, or tell them to get screened earlier.”
Women should not be distressed no matter their birth size, says Dr. Debbie Saslow, PhD, director of breast and gynecologic cancer at the American Cancer Society. While the study has research interest to scientists, she says, it does not trigger any new clinical advice for women.
In an accompanying editorial to the study, Harvard researchers (including a scientist who published a paper back in 1990 about breast cancer possibly originating from the womb) calls the findings “the strongest evidence to date that birth is a critical determinant of breast cancer risk in adult life.”
In another newly released study, researchers found shorter, more intense radiation therapy following surgery for early stage breast cancer is just as effective as lower doses for a longer period.
Study findings suggest women that are diagnosed with breast cancer may undergo shorter treatment cycles, allowing them to get back to their families and regular routines quicker, researchers said. #