Link between Breast and Ovarian Cancer: Identified Risk Factors
Breast and ovarian cancer share significant genetic and environmental risk factors, leading to an increased probability of developing both diseases. The connection is particularly strong for individuals who carry mutations in the BRCA1 and BRCA2 genes.
Genetic mutations are the most significant shared risk factors for breast and ovarian cancers. Approximately 4 percent of families with ovarian and breast cancer have BRCA1 gene mutations, while around 20 percent have BRCA2 mutations.
Other shared risk factors include family history, older age, overweight or obesity, having a first child at an older age, never having children, not breastfeeding, hormone therapy after menopause, and certain reproductive factors such as early menstruation and late menopause.
Research suggests that people with breast cancer are roughly twice as likely to develop subsequent primary ovarian cancer. The risk is higher for those with breast cancer linked to genetic mutations such as BRCA1 or BRCA2. Conversely, those with ovarian cancer may have a 1.6-fold increased risk of subsequent breast cancer, though the risk varies with time since their first cancer diagnosis.
Individuals with a history of either breast or ovarian cancer can work with their healthcare team to monitor signs of another cancer. Regular screenings, such as mammograms, breast MRI scans, pelvic exams, transvaginal ultrasounds, and CA-125 blood tests, may be recommended. Genetic testing for BRCA1, BRCA2, and other relevant mutations is an essential strategy for monitoring and prevention.
For those carrying genetic mutations, doctors may consider additional options such as prophylactic surgeries to remove organs or tissues and prevent the occurrence or spread of cancer.
Modifiable risk factors include maintaining a moderate weight, regular exercise, limiting alcohol intake, and oral contraceptives. Achieving and maintaining a moderate weight can reduce the risk of breast and ovarian cancer due to the effects on estrogen levels. Regular physical activity reduces the risk of breast cancer, and exercise's anticancer effects are limited but supported for ovarian cancer. Reducing alcohol intake, oral contraceptives, and discussing contraception options with a doctor can help weigh the risks based on individual circumstances.
Despite the shared risk factors, the prognosis for people with both primary breast cancer and primary ovarian cancer is relatively favorable, with 5- and 10-year overall survival rates of around 90 percent. The outlook is generally more positive when the interval between the two diseases is longer, but ovarian cancer following breast cancer tends to be diagnosed at a later stage, which can negatively affect survival. Age during the first cancer diagnosis and the time between the two cancers are significant predictors of overall survival.
Monitoring signs of recurrence or a second cancer is crucial for those with a previous diagnosis of breast or ovarian cancer. Early detection and prompt treatment are essential for improving outcomes.
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People at high risk of ovarian cancer include those with BRCA1 or BRCA2 gene mutations, a family history of ovarian, breast, or colorectal cancer, Lynch syndrome, endometriosis, never been pregnant, had a late first pregnancy, or are over 40 years old.
While outside the primary focus, additional shared risk factors include cardiac glycosides, certain medications with potential estrogenic effects, and dietary patterns. A diet high in vegetables, fruits, and soybeans is associated with a lower risk of breast cancer and may have similar effects on ovarian cancer risk. Obesity and unhealthy lifestyle choices are proposed as potential shared risk factors, although the evidence is not as strong as for other factors.
- Genetic mutations in BRCA1 and BRCA2 genes significantly increase the risk of both breast and ovarian cancers.
- Approximately 4% of families with ovarian and breast cancer have BRCA1 gene mutations, while around 20% have BRCA2 mutations.
- Other shared risk factors include family history, older age, overweight or obesity, hormone therapy after menopause, certain reproductive factors, and modifiable factors like maintaining a moderate weight, regular exercise, limiting alcohol intake, and oral contraceptives.
- People with breast cancer are twice as likely to develop subsequent primary ovarian cancer, and the reverse is also true, though the risk varies with time since the first cancer diagnosis.
- For those carrying genetic mutations, doctors may consider additional options such as prophylactic surgeries to remove organs or tissues and prevent the occurrence or spread of cancer.
- Monitoring signs of recurrence or a second cancer is crucial for those with a previous diagnosis of breast or ovarian cancer, and early detection and prompt treatment are essential for improving outcomes.
