Early breast cancer screening may help some: study
Starting breast cancer screening as early as age 25 may help women who carry a genetic mutation linked to a higher risk of cancer live longer, suggests a new study.
“Results indicate that breast cancer deaths will decrease because of screening,” study co-author Dr. Janie Lee, who specializes in breast imaging at Massachusetts General Hospital, said by email.
Researchers looked at which breast cancer screenings - mammogram or magnetic resonance imaging (MRI) - were effective in women who carry gene mutations BRCA1 and BRCA2, known to increase the risk of breast and ovarian cancer. They looked at women aged 25, 30, 35 and 40 years.
The study, reported in the journal Cancer, found that compared to no screening at all, annual screening starting at age 25 extended life by 1.3 to 1.8 years. Screening with a breast MRI every six months extended life by 1.5 to 1.7 years.
The tests were not perfect. Over the course of their lives, women with BRCA1 who began having mammograms at the age of 25 would have two false positives - a finding that doesn’t turn out to be cancer. Those women with BRCA1 who had an annual mammogram and breast MRI would have four false positives.
For BRCA2 carriers, the corresponding numbers of false positives were three and eight.
The authors based their findings on a computer model that may not translate into real life, noted Dr. Carol Fabian, who specializes in breast cancer research at the University of Kansas and was not part of the study.
“This is a model so they are applying things that have been learned in other studies,” Fabian told Reuters Health.
The importance of finding breast cancer early
The goal of screening exams for early breast cancer detection is to find cancers before they start to cause symptoms. Screening refers to tests and exams used to find a disease, such as cancer, in people who do not have any symptoms. Early detection means using an approach that lets breast cancer get diagnosed earlier than otherwise might have occurred.
Breast cancers that are found because they are causing symptoms tend to be larger and are more likely to have already spread beyond the breast. In contrast, breast cancers found during screening exams are more likely to be smaller and still confined to the breast. The size of a breast cancer and how far it has spread are some of the most important factors in predicting the prognosis (outlook) of a woman with this disease.
Most doctors feel that early detection tests for breast cancer save thousands of lives each year, and that many more lives could be saved if even more women and their health care providers took advantage of these tests. Following the American Cancer Society’s guidelines for the early detection of breast cancer improves the chances that breast cancer can be diagnosed at an early stage and treated successfully.
In women 40 years or younger with breast cancer, about 1 in 10 are likely to have a BRCA mutation, according to the National Cancer Institute.
The United States Preventive Services Task Force, a government-funded agency, recommends breast cancer screening for all women beginning at age 50. BRCA carriers are encouraged to start screening at a young age by groups such as the American Cancer Society, which recommends screening at age 30, five years later than when the study suggests.
“Starting at 25 years may have a slight benefit, but for most women 30 is good too,” said Dr. Debbie Saslow, director of breast and gynecologic cancer for the American Cancer Society.
“For women who have a BRCA mutation in their family, they tend to get diagnosed at age 40 or younger so they should consider screening at age 25,” she said.
When breast cancer starts, it is too small to feel and does not cause signs and symptoms. Mammograms help doctors look for early signs of breast cancer. If breast cancer is found early, it may be possible to treat it before it spreads.
In 2008, more than 75% of women over 40 reported having a mammogram in the past 2 years. However, women may have questions about when to start getting regular mammograms and about the benefits and potential harms. Physicians and other health care providers may also want to better understand the scientific evidence about the use of screening mammograms.
Still, annual screenings can add up to high costs. MRIs can cost more than $1,000, while mammograms cost less than $200. Saslow said that insurance companies typically cover women considered high-risk.
Another concern with screening is repeated radiation exposure, especially among those at increased risk of breast cancer.
When researchers factored in radiation risk, they found fewer than 5 out of 100 women who were BRCA carriers were diagnosed with breast cancer due to exposure to radiation.
“The risk of getting breast cancer from radiation is small compared to the risk of dying from breast cancer if you don’t get screening,” Fabian said. “It’s an acceptable tradeoff.”
Source: Annual screening strategies in BRCA1 and BRCA2 gene mutation carriers - Cancer, September 20, 2011.