Risk factors
Alcohol consumption is linked to breast cancer development in a dose-dependent manner.
In a recent American Cancer Society study in postmenopausal women, it was shown that one drink a day increased the risk of dying of breast cancer up to 30%, compared to non-drinkers. Alcohol consumption has also been linked to increased risk of gastrointestinal cancers (mouth, larynx, pharynx, esophagus, and liver), and head and neck cancers. Women who drink <2 drinks/ week are considered to be at low risk of developing alcohol-related diseases. Consuming >7 drinks/ week places a woman at higher risk of developing alcohol-related diseases. Men who drink drinks/ week are considered to be at low risk of developing alcohol-related complications, while those who drink >14 drinks/ week are considered high risk. Additionally, the relative risk of alcohol consumption for the development of breast cancer is greater than the relative risk of obesity in the development of breast cancer.
Pregnancy, late menarche, and breastfeeding have been correlated with decreased risk of breast cancer. These conditions reduce the number of ovulatory cycles in a woman's lifetime, which is why they are believed to be protective against breast cancer.
While high-risk sexual behavior can lead to sexually transmitted diseases such as human papillomavirus and thus cervical cancer, having multiple sexual partners is not known to impact breast cancer development.
Obesity is a significant risk factor for breast cancer development among postmenopausal women. This patient has a BMI of 20 which is not in the obese range. In premenopausal women, however, obesity is associated with a lower risk of breast cancer. The reasons for this lower risk remain unclear. Although the patient in this vignette is obese (and is likely postmenopausal), there is yet another element of her history is a more significant risk factor for the development of breast cancer.
The relationship between smoking and breast cancer is still an active field of research. Preliminary results indicate that it may increase the risk of breast cancer in premenopausal women while reducing the risk in postmenopausal women.
Tamoxifen is a SERM which acts as an oestrogen receptor antagonist and partial agonist. It is used in the management of oestrogen receptor-positive breast cancer.
Adverse effects
Anastrozole and letrozole arearomatase inhibitors that reduces peripheral oestrogen synthesis. This is important as aromatisation accounts for the majority of oestrogen production in postmenopausal women and therefore anastrozole is used for ER +ve breast cancer in this group.
Adverse effects