Breast cancer is commonly treated by various combinations of surgery, radiation therapy, chemotherapy, and hormone therapy. Prognosis and selection of therapy may be influenced by the following clinical and pathology features (based on conventional histology and immunohistochemistry):
- The menopausal status of the patient.
- The stage of the disease.
- The grade of the primary tumor.
- The estrogen receptor (ER) and progesterone receptor (PR) status of the tumor.
- Human epidermal growth factor type 2 receptor (HER2/neu) overexpression and/or amplification.
- The histologic type. Breast cancer is classified into a variety of histologic types, some of which have prognostic importance. For example, favorable histologic types include mucinous, medullary, and tubular carcinomas.[83,84,85]
The use of molecular profiling in breast cancer includes the following:
- ER and PR status testing.
- HER2/neu receptor status testing.
- Gene profile testing by microarray assay or reverse transcription-polymerase chain reaction (e.g., MammaPrint, Oncotype DX).
On the basis of these results, breast cancer is classified as:
- Hormone-receptor positive.
- HER2 positive.
- Triple negative (ER, PR, and Her2/neu negative).
Although certain rare inherited mutations, such as those of BRCA1 and BRCA2, predispose women to develop breast cancer, prognostic data on BRCA1 /BRCA2 mutation carriers who have developed breast cancer are conflicting; these women are at greater risk of developing contralateral breast cancer.
Hormone replacement therapy
After careful consideration, patients with severe symptoms may be treated with hormone replacement therapy. For more information, refer to the following PDQ summaries:
The frequency of follow-up and the appropriateness of screening tests after the completion of primary treatment for stage I, stage II, or stage III breast cancer remain controversial.
Evidence from randomized trials indicates that periodic follow-up with bone scans, liver sonography, chest x-rays, and blood tests of liver function does not improve survival or quality of life when compared with routine physical examinations.[87,88,89] Even when these tests permit earlier detection of recurrent disease, patient survival is unaffected. On the basis of these data, acceptable follow-up can be limited to physical examination and annual mammography for asymptomatic patients who complete treatment for stages I to III breast cancer.