Cytotoxic chemotherapy and hormonal therapy have inherent risks that must be considered when treatment decisions are made. There are many known acute side effects with standard regimens, and there is growing evidence that patients who undergo chemotherapy report more frequent chronic neurocognitive deficits than do untreated controls (81). The impact of these deficits remains undefined. Systemic therapy with tamoxifen is associated with an increased incidence of uterine cancer, vaginal dryness, and hot ﬂashes, whereas aromatase inhibitors are linked to osteoporosis and musculoskeletal symptoms. Choosing those patients who should receive adjuvant therapy can be a difficult decision that often entails analyzing a variety of prognostic and predictive factors, identifying patients at risk for recurrence, and quantifying that risk. Based on available data, adjuvant chemotherapy is recommended for women with greater than a 10% chance of relapse within 10 years. The choice of therapy depends on an evaluation of specific risk factors. Two multigene assays such as the Oncotype DX and the Mammaprint have been introduced to help identify those estrogen receptor–positive, lymph node–negative patients who will benefit most from systemic chemotherapy. These tests, which calculate a recurrence risk score for each individual based on a 21-gene assay and 70-gene signature, respectively, allow the treating physician to determine the average rate of distant disease at 10 years and make treatment recommendations based on this risk (82).
Prognostic Indicators Factors that determine each patient’s risk of recurrence include nodal involvement, tumor size, estrogen and progesterone receptor status, nuclear grade, histologic type, proliferative rate, and biologic markers such as Her-2/neu status. These prognostic factors and their effects on recurrence are summarized in Table 40.4. Patients with high-risk prognostic factors are more likely to benefit from adjuvant cytotoxic or hormonal therapy and usually are offered such treatment.
Table 40.4 Prognostic Factors in Node-Negative Breast Carcinoma
From Giuliano AE, Hurvitz SA. Breast Disorders. In: McPhee SJ, Papadakis MA, eds. 2011 current medical diagnosis and treatment. New York: McGraw Hill, 2011;710, with permission.
Table 40.5 Year Survival According to Stage of Breast Cancer
AJCC, American Joint Committee on Cancer. From Giuliano AE, Hurvitz SA. Breast disorders. In: McPhee SJ, Papadakis MA, eds. 2011 current medical diagnosis and treatment. New York: McGraw Hill, 2011;716, with permission.
Patients with lymph node metastasis have a higher risk of recurrence than patients with node-negative disease. The 10-year survival rate for women with palpable metastatic axillary lymph nodes who fail to receive systemic therapy is about 50% to 60%. The number of lymph nodes involved and the presence of extracapsular invasion are important indicators of poor prognosis.
Another prognostic indicator of relapse is primary tumor size. In an evaluation of 767 patients with node-negative disease who underwent radical or modified radical mastectomy without adjuvant chemotherapy, the relapse rate in patients with tumors larger than 1 cm or special tumor types larger than 3 cm (tubular, mucinous, or papillary) was 27% at 10 years, compared with 9% for tumors smaller than 1 cm (83).