••• Chapter 41^ Breast Disorders^413
❍ How does the status of HER-2/neu affect the prognosis in breast cancer?
It is associated with decreased survival when overexpressed in tumor cells.
❍ What percent of breast cancers are HER-2/neu positive?
20%.
❍ What is HER-2/neu and where is it located?
It is a proto-oncogene found on chromosome 17q21-22, and it has structural similarity to the epidermal growth
factor receptor.
❍ What drug can be used as a single agent or can be added to first-line chemotherapy in HER-2/neu receptor
positive to improve outcome?
Herceptin (trastuzumab), which is a recombinant, humanized monoclonal antibody directed against the HER-2/
neu product.
❍ What is the most significant side effect of Herceptin?
Cardiotoxicity.
❍ What is the risk of developing breast cancer in association with caffeine consumption and cigarette
smoking?
There is no substantial data to prove a causative effect of either substance.
❍ What structure within the breast gives rise to all carcinomas?
The terminal duct lobular unit.
❍ What is the most common type of in situ carcinoma and invasive carcinoma?
Ductal carcinoma accounts for 80% of the in situ lesions and 80% of the invasive lesions.
❍ What are the various treatment options for a patient with breast carcinoma?
- Breast conservation therapy, which consists of lumpectomy plus radiation or mastectomy.
- Radiation is indicated after mastectomy for tumors >5 cm, chest wall invasion, and/or 4 or more positive lymph
nodes. - Chemotherapy is used in patients with tumors >1 cm, positive lymph nodes, young age, and aggressive tumor
factors. - Herceptin is used if the tumor is positive for the HER2/neu receptor.
- Antiestrogens are used if the tumor is ER/PR+.
- In premenopausal women, tamoxifen is used.
- In postmenopausal women, either tamoxifen or aromatase inhibitors are used.
❍ What is required to qualify for breast conservation therapy?
The tumor should be <5 cm, without any associated inflammatory carcinoma, skin nodules, or ulcerations, and
with a favorable ratio of breast size to tumor size such that the patient would have a good cosmetic result.