Breast Cancer Risk in Young Women
Most breast cancer (65-70%) occurs in women over 50 years of age. Only 1 in 2500 women develop breast cancer by age 30 and only 1 in 200 women develop it by age 40. Younger women who develop breast cancer are more likely to have genetic risk factors. It is almost as if there are two different types of breast cancer, that occurring rarely, but before menopause and that occurring more commonly, but after menopause.
A recent article, Vogel VG: Breast cancer in younger women: Assessment and risk management. The Female Patient 1999;24:81-86, looks at risk factors and what can be done to prevent breast cancer if a woman is at greatly increased risk for breast cancer.
It is normal to be concerned about developing breast cancer because this is a common (one in 9-11 lifetime risk) cancer. However it is unhealthy to be overly concerned about it. Many women develop a significant degree of anxiety about possible cancer because they overestimate their chance of getting it. Some studies show that women overestimate their annual chance of getting breast cancer by 20-60 fold. In fact some women who are at increased risk for breast cancer experience as much stress and anxiety as women actually diagnosed with invasive breast cancer.
Keep in mind that most factors that have been associated with an increased incidence of breast cancer are just that -- associations -- they are not necessarily cause and effect. In other words, women who have these "associated" risks may actually use or be exposed to other agents or factors that are the causative or promoter agents.
|Risk Factor||Risk Category||Relative Risk||Women Affected
|Age at menstrual onset||less than 12 years of age vs 16 years of age||1.3||16%|
|Age at menopause||greater than 55 years of age vs 45-54 years old||1.5||6%|
|Age at first live birth||over 30 years of age or no children||1.9||21%|
|Benign breast disease||any benign disease biopsied vs no biopsy or fine needle aspiration||1.5||15%|
|benign proliferative disease biopsy vs no biopsy or fine needle aspiration||2.0||4%|
|atypical hyperplasia biopsy vs no biopsy or fine needle aspiration||4.0||1%|
|Family history of breast cancer||mother with breast cancer vs no mother, sister, daughter affected||1.7||8%|
|two first degree relatives with breast cancer vs no mother, sister, daughter affected||5.0||4%|
|Obesity||90th percentile for weight vs 10th percentile for weight||1.2||10%|
|Alcohol Use||moderate drinker vs nondrinker||1.7||12%|
|Estrogen Replacement Therapy Use||current use for 5 years or more vs never use||1.5||18%|
Why not just start mammograms at a much earlier age, say in the 30's to pick up cancer earlier?
Two reasons are usually cited for not just starting mammograms earlier:
- There are risks, complications, and discomforts due to early and regular mammograms
- Reductions in death and morbidity due to breast cancer have not been shown to be worth the costs of mammogram screening on a regular basis in women under 40
The disadvantages of routine mammograms at a younger age include more years of radiation exposure to the breast which may in turn promote a breast cancer, physical pain from the breast compression during mammography, the increased anxiety and unnecessary testing due to many false positives, potential over treatment of diagnosed lesions that are not life threatening, false reassurance from negative studies that just happened to miss lesions because they were too small or the breasts were too dense to see them, and simply the anxiety naturally occurring between scheduling the screening procedure and receiving the results.
If I have a strong family history of breast cancer should I get genetic testing?
If you have any relative who has had breast cancer and is still alive, that person should be encouraged to ask their doctor if they (not you) can undergo genetic testing for known breast cancer associated genes. Then if they have positive tests for genetically linked breast cancer, you should have genetic counselling and possibly testing.
If you have more than one first-degree relative (mother, sister, daughter) with breast cancer, any female relatives who developed breast cancer before menopause or age 50 or had both breasts involved, or any male relative who developed breast cancer, then you need to see a genetic counselor for advice about testing.
If I am at very high risk for breast cancer, can I do anything to prevent it or lower my risk?
The most commonly used medicine to prevent breast cancer recurrence or even to prevent the occurrence of a new breast cancer is tamoxifen. It is effective at reducing by about 50% the incidence of a new breast cancer. It can have significant side effects and complications so it is only used for women who are at high risk for breast cancer. Side effects and complications include:
- increased endometrial cancer
- increased heart attacks and strokes
- increased blood clots
- side effects from low estrogen blood levels such as vaginal dryness, hot flashes, more frequent urinary tract infections, and pain with sexual relations
There are some women, however, whose risk is so high for breast cancer development that they need to consider taking tamoxifen for prevention and risk the tamoxifen side-effects and complications. These include:
- a history of lobular carcinoma in situ (not invasive, just confined to the upper skin layer) by previous biopsy
- a history of ductal carcinoma in situ by previous biopsy
- a history of atypical ductal/lobular hyperplasia by previous biopsy
- known genetic mutations, BRCA1, BRCA2 and others, by genetic testing
- a premenopausal woman with a 5 year probability of breast cancer of more than 1.7% as determined by multivariate risk prediction models
I have heard that some women who are at very high risk for breast cancer actually have surgery to remove the breasts in order to prevent cancer. Is that true?
Yes, it is true, but there are very few indications for having a "prophylactic breast removal (mastectomy)." It is better for women at high risk for breast cancer to take tamoxifen and be under very close medical surveillance with exams and imaging studies than to undergo breast removal just to prevent breast cancer. While some women who have undergone prophylactic mastectomy report significant emotional relief, it is important to remember that bilateral mastectomies only prevent 90% of subsequent invasive breast cancers.
The following women might consider prophylactic mastectomy:
- those unwilling to consider tamoxifen therapy for primary prevention
- those who have been shown to be genetic carriers for breast cancer predisposing genes
- in the absence of genetic testing, those who have a family history suggesting a genetic syndrome such as bilateral disease, premenopausal breast cancer in one or more first-degree relatives, or multiple affected relatives in several generations
- women with a high risk score or a lifetime risk of breast cancer over 20%
- women with a family history of breast cancer in a first-degree relative plus a breast biopsy showing atypical hyperplasia or in situ lobular or intraductal cancer
- those with an increased objective risk plus repeated breast biopsies with significant scarring resulting in difficult physical exams or mammogram examinations showing multiple nodular densities
- women with almost a major psychological disability due to extreme fear of cancer
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