A young woman with a breast mass: What every internist should know
RISK FACTORS FOR BREAST CANCER
3. Which of the following are risk factors for breast cancer?
- Menarche before age 12
- Female sex
- Personal history of breast cancer
- Obesity
- Never having had children, or having given birth for the first time at an older age
- Older age
- History of hormone replacement therapy with estrogen and progesterone
- Family history of breast cancer
All of these choices are risk factors for breast cancer.
Family history
The overall relative risk of developing breast cancer in a woman with a first-degree relative with the disease is 1.7. However, the relative risk is about 3 if the first-degree relative developed breast cancer before menopause, and 9 if the first-degree relative developed bilateral breast cancer before menopause.5
Estrogen exposure
The duration and amount of estrogen exposure are also risk factors. For example, menarche before age 12 and menopause after age 55 are associated with a higher risk. Women who go through menopause after age 55 have a twofold higher risk of breast cancer compared with women who go through menopause at an early age. Pregnancy before age 30 lowers the risk of breast cancer; late first full-term pregnancy or nulliparity increases it. Lactation, on the other hand, has a protective effect.5
Oral contraceptives have traditionally been thought to increase the risk of breast cancer. In the 1990s, a meta-analysis involving 153,506 women found that those who had used oral contraceptives had a 24% higher risk of developing breast cancer.26 However, this association has come into question since newer oral contraceptive pills containing different progestins and lower amounts of estrogen have become available. In fact, recent studies showed no link between oral contraceptive use and breast cancer.27,28 Nevertheless, women at higher risk of developing breast cancer are advised not to use oral contraceptives.
Hormone replacement therapy with estrogen and progesterone was found to increase the risk of breast cancer by 26% in the Women’s Health Initiative (WHI) study, which involved 16,608 healthy women followed for a median of 5.6 years.29
In a study reported separately, the WHI investigators randomized 10,739 women who had undergone hysterectomy to receive either hormone replacement therapy with unopposed estrogen (which is feasible only in women without a uterus) or placebo. They found no increase in the risk of invasive breast cancer in women on hormone replacement therapy with estrogen alone. In fact, the study showed a trend towards a modest reduction of this risk (odds ratio 0.77; 95% confidence interval 0.59–1.01).30
After the results of the WHI were published, the use of hormone replacement therapy in postmenopausal women declined significantly. And in 2003—1 year later—the incidence of breast cancer had dropped by 6.7%.31
Most experts now recommend that estrogen-progestin combinations be used only selectively to treat the symptoms of menopause, and only for the short term.
Other risk factors
Other factors found to modestly increase the risk of breast cancer include:
- Alcohol use
- Obesity
- Radiation exposure. Patients are at higher risk of breast cancer 15 to 20 years after receiving upper-mantle radiotherapy for Hodgkin lymphoma.5
Case continues: Bad news on mammography, ultrasonography, biopsy
The patient undergoes mammography, which shows a 2.5-cm spiculated lesion with areas of calcifications (BIRADS score of 5). Subsequently, ultrasonography confirms that the suspicious mass is not a cyst. Ultrasound-guided core needle biopsy reveals that the lesion is a high-grade invasive ductal carcinoma. The tumor is positive for both estrogen and progesterone receptors and negative for HER2/neu overexpression.
STAGING EVALUATION
4. Given these findings, what is the next step to take?
- CT of the chest, abdomen, and pelvis
- MRI of the brain
- PET
- Referral to a surgeon for a possible mastectomy with sentinel lymph node dissection
- Referral to a surgeon for a possible lumpectomy with sentinel lymph node dissection
At this point, the patient should be referred to a surgeon for possible mastectomy or lumpectomy.
Women who appear clinically to have early breast cancer, such as in this case, should have a complete blood count, comprehensive metabolic panel, and chest x-ray as their initial staging evaluation. No further studies are recommended unless the findings on history, physical examination, or the above testing suggest possible metastases.
