Ovary Removal, MRI Screening for Breast Cancer Saves Lives in Women With BRCA Mutation
MRI breast cancer screening and removing the ovaries can help save the lives of women with a BRCA1 or BRCA2 mutation, according to two studies.
Both research papers were published online on Feb. 29, 2024, by the journal JAMA Oncology:
Read the abstract of “Bilateral Oophorectomy and All-Cause Mortality in Women With BRCA1 and BRCA2 Sequence Variations.”
Read “MRI Surveillance and Breast Cancer Mortality in Women With BRCA1 and BRCA2 Sequence Variations.”
BRCA mutations and cancer risk
Women with a BRCA1 or BRCA2 mutation have a much higher-than-average risk of breast and ovarian cancer. About 13% of women in the general population in the United States develop breast cancer sometime during their lives. But about 72% of women with a BRCA1 mutation and about 69% of women with a BRCA2 mutation develop breast cancer by age 80. 1 Similarly, about 44% of women with a BRCA1 mutation and 17% of women with a BRCA2 mutation develop ovarian cancer by age 80, compared with 1% to 2% of U.S. women in the general population. 2
Why do the studies?
Preventive surgery – such as removing the healthy breasts (prophylactic mastectomy) and ovaries and fallopian tubes (prophylactic salpingo oophorectomy) – as well as more frequent screening with mammography and other techniques can help reduce the risk of developing breast and ovarian cancer in women with a BRCA mutation. The researchers did these studies to provide more information on how these strategies can help reduce the risk of dying from breast or ovarian cancer and other causes.
About the ovary removal study
The researchers collected information from a group of 4,332 women from 16 countries around the world:
3,177 (73%) had a BRCA1 mutation
1,155 (27%) had a BRCA2 mutation
The women’s average age was about 43 years. None of the women had been diagnosed with cancer when they joined the study.
The women filled out a questionnaire when they joined the study and then every two years after that. Among other health information, the questionnaires asked the women about:
any surgeries they had
their use of hormone replacement therapy (HRT) and birth control pills
any cancer diagnoses they had
Overall, 2,932 women had prophylactic oophorectomy:
2,106 women (66.3%) with a BRCA1 mutation
826 women (71.5%) with a BRCA2 mutation
The women were followed for up to 24 years; average follow-up time was nine years.
The researchers noted how many women were diagnosed with any type of cancer, how many women died, and the cause of death. They then looked to see how prophylactic oophorectomy affected mortality.
During follow-up, 901 cases of cancer were diagnosed among 851 of the women. There were:
582 breast cancers; 496 were invasive breast cancer and 86 were DCIS
140 ovarian or fallopian tube cancers; 94 were detected because of screening or symptoms and 46 were diagnosed during prophylactic oophorectomy
35 peritoneal cancers (cancer of the lining of the abdomen, uterus, and rectum)
144 other types of cancer
A total of 228 women died during follow-up:
182 (80%) died from cancer
28 (12.3%) died from other causes
18 (7.9%) had an unknown cause of death
Of the women who died from cancer, about 50% died from breast or ovarian cancer:
58 (25%) died from breast cancer
55 (24%) died from ovarian cancer
A higher percentage of women who didn’t have prophylactic oophorectomy died during follow-up:
112 of the 2,932 women (3.8%) who had prophylactic oophorectomy died
116 of the 1,400 women (8.3%) who didn’t have prophylactic oophorectomy died
The researchers’ calculations showed that prophylactic oophorectomy was linked to lower rates of death from any cause. Among women who had prophylactic oophorectomy:
death rates were 72% lower among women with a BRCA1 mutation
death rates were 57% lower among women with a BRCA2 mutation
Both of these lower rates were statistically significant, which means they were likely due to the prophylactic oophorectomy and not just because of chance.
The researchers then estimated annual mortality rates for the women, based on BRCA status and whether they had prophylactic oophorectomy or not.
Mortality from all causes by age 75 for women who had prophylactic oophorectomy at age 35:
dropped from 62% to 25% among women with a BRCA1 mutation
dropped from 28% to 14% among women with a BRCA2 mutation
“The data … support the current National Comprehensive Cancer Network guidelines for oophorectomy between ages 35 and 40 years for women with BRCA1 sequence variations and before age 45 years for women with BRCA2 sequence variations,” the researchers concluded. “We hope that the findings in this study will reassure women with a positive genetic test result who face high risks of breast and ovarian cancer.”
About the MRI screening study
The researchers looked at information from 2,488 women:
2,004 had a BRCA1 mutation
484 had a BRCA2 mutation
The women lived in 11 countries around the world and ranged in age from 30 to 69:
2,421 (97.3%) were white
25 (1%) were Asian
5 (0.2%) were Black
37 (1.5%) were another race or ethnicity
None of the women had been diagnosed with cancer when the study started.
The women joined the study between 1995 and 2015. They filled out a baseline questionnaire when they joined and then every two years after that. The questionnaires asked the women about:
any surgeries they had
their use of HRT and birth control pills
if they were part of an MRI surveillance program, and if so, when they had MRIs
any breast cancer diagnoses they had
The women were followed for up to 24 years; average follow-up time was 9.2 years.
A total of 1,756 women (71%) had MRI screening in the year they joined the study or the next year. The women were about 43 years old when they had the first screening MRI. The researchers called these women the MRI surveillance group. These women had between one and 16 screening MRIs over the course of the study; the average number of MRIs the women received was five. Among the 1,365 women who had two or more screening MRIs, the average time between MRIs was about a year.
Of the 732 women who weren’t in the MRI surveillance group, 636 (86.7%) said they had had at least one mammogram.
Of the women in the MRI surveillance group, 245 (14%) had prophylactic mastectomy after the study started, compared to 119 (16.3%) of the women who weren’t having MRI surveillance. Doctors found breast cancer in 11 women during prophylactic mastectomy.
During follow-up, 344 cases of breast cancer were diagnosed:
284 (82.6%) were invasive disease
50 (14.5%) were DCIS
10 (2.9%) were missing information about breast cancer type
Overall, 92 women died during the study:
35 (1.4%) died from breast cancer
51 (2%) died from other causes
6 (0.24%) were missing information about cause of death
Among the women in the MRI surveillance group, 241 breast cancers were diagnosed and 14 women died from breast cancer. In five of the 14 women, breast cancer was diagnosed at the first MRI screening. Among the women who weren’t having MRI surveillance, 103 breast cancers were diagnosed and 21 women died from breast cancer.
After the researchers took into account the women’s age, oophorectomy status, where the women lived, and other factors, the results showed that MRI surveillance was linked to 77% lower breast cancer mortality.
The researchers then looked specifically at the type of BRCA mutation to see if MRI surveillance was more beneficial for one group:
Women with a BRCA1 mutation had 80% lower breast cancer death rates.
Women with a BRCA2 mutation had 13% lower breast cancer death rates.
Only the lower death rates in women with a BRCA1 mutation were statistically significant. This means the lower death rates were likely due to the MRI surveillance and not just because of chance.
The lower death rates in women with a BRCA2 mutation were not statistically significant, which means the results could have happened by chance.
“This cohort study supports the recommendation that women with BRCA1 sequence variations aged 30 years or older should be offered MRI surveillance,” the researchers wrote. “We observed an 80% reduction in breast cancer mortality for women with BRCA1 sequence variations after they entered an MRI surveillance program. Further follow-up in women with BRCA2 sequence variations is needed to ascertain whether these patients obtain the same benefits associated with MRI surveillance.”
What this means for you
These two studies show that breast cancer prevention strategies for women with a BRCA mutation save lives.
If you know you have a BRCA1 or BRCA2 mutation, it makes sense to talk to your doctor about all the steps you can take to keep your risk of breast cancer as low as it can be, including having a screening MRI every year and preventive surgery.
If you don’t know if you have a mutation but have a strong family history of breast cancer (a sister, mother, daughter, or any man in your family has been diagnosed), you may want to talk to your doctor about whether genetic counseling and testing makes sense for you.
Once you have all the information possible, you and your doctor can figure out your personal risk of breast cancer and develop a screening and risk-reducing plan that’s best for your unique situation and preferences.
Kuchenbaecker, K. et al. Risk of Breast, Ovarian, and Contralateral Breast Cancer for BCAA! and BRCA2 Mutation Carriers. JAMA. 2017 June 20. link: https://pubmed.ncbi.nlm.nih.gov/28632866/
Kuchenbaecker, K. et al. Risk of Breast, Ovarian, and Contralateral Breast Cancer for BCAA! and BRCA2 Mutation Carriers. JAMA. 2017 June 20. link: https://pubmed.ncbi.nlm.nih.gov/28632866/
Updated on July 18, 2024