Review Question - QID 214581

This patient is newly diagnosed with breast cancer. The most appropriate next step is to determine the tumor size for TNM (Tumor, Node, and Metastasis) staging, which is the most important prognostic factor.

Breast cancer is the most common cancer diagnosed in women and arises from cells within the breast. There are a number of types of breast cancer, which include lobular, ductal, tubular, mucinous, medullary, papillary, metaplastic, and inflammatory. Diagnosis is made via a diagnostic mammogram followed by a confirmatory biopsy. Following diagnosis, the most important step is to determine the stage of the tumor, which consists of tumor size (T), lymph node involvement (N), and the presence of metastasis (M). Various cutoffs for the 3 factors are combined to determine the stage; it is worth noting that the presence of metastasis automatically stages the tumor at stage IV regardless of tumor size or lymph node involvement. Staging is the most important prognostic factor, and the 5-year relative survival rates are determined by the stage (e.g., 95% for stage I). The stages range from stage I-IV with stage IV having the worst prognosis.

Incorrect Answers:
Answer 1: Breast cancer receptor testing is important in determining therapy. Although the presence of estrogen and progesterone receptors are generally associated with a better outcome, TNM staging is still the most important prognostic factor. Estrogen/progesterone positive tumors can be treated with hormonal therapies (e.g., tamoxifen) while human epidermal growth factor receptor (HER2) positive tumors can be treated with trastuzumab.

Answer 3: Genetic testing may be appropriate in this patient who has a family history of breast cancer. This may be helpful in determining the patient and her family members' chances for future malignancies. However, this is not the most appropriate next step in determining this patient’s prognosis.

Answer 4: Histologic grade of breast cancer is assigned using the Elston-Ellis grading system, which characterizes the degree of tumor differentiation by certain histologic findings (e.g., level of mitotic activity). Poorly differentiated tumors are often associated with worse outcomes; however, the tumor stage still remains the most important prognostic factor.

Answer 5: Whole-body PET imaging or other whole-body imaging studies are often indicated in patients with stage IIIA or higher tumors (or patients with inflammatory breast cancer). They are not indicated in patients with lower stages as the radiation risk of whole-body imaging outweighs the benefits. The need for whole-body PET imaging is determined only after staging.

Bullet Summary:
TNM staging, which accounts for tumor size, lymph node involvement, and metastasis, is the most important prognostic factor for breast cancer.