Staging of breast cancer in the neoadjuvant setting

Abstract

The use of neoadjuvant chemotherapy has become more prevalent in the treatment of breast cancer patients. The finding of a pathologic complete response to neoadjuvant chemotherapy (no evidence of residual invasive cancer in the breast and lymph nodes at the time of surgical resection) has been shown to correlate with improved survival. The current version of the American Joint Committee on Cancer (AJCC) staging for breast cancer has a pretreatment clinical stage designation that is determined by clinical and radiographic examination of the patient and a postoperative pathologic stage classification based on the findings in the breast and regional lymph nodes removed at surgery. Pathologic staging has not been validated for patients receiving neoadjuvant chemotherapy; thus, prognosis is determined for these patients based on the pretreatment clinical stage. We hypothesized that clinical and pathologic staging variables could be combined with biological tumor markers to provide a novel means of determining prognosis for patients treated with neoadjuvant chemotherapy. Two scoring systems, based on summing binary indicators for clinical and pathologic substages, negative estrogen receptor status, and grade 3 tumor pathology, were devised to predict 5-year patient outcomes. These scoring systems facilitated separation of the study population into more refined subgroups by outcome than the current AJCC staging system for breast cancer, and provide a novel means for evaluating prognosis after neoadjuvant therapy.

Figure 1

DSS for pathologic stage IIA patients stratified by the CPS-EG scoring system. Through application of the CPS-EG scoring system to AJCC pathologic stage IIA patients, 5 prognostic groups were determined having the following 5-y DSS outcomes: score 1, 100%; score 2, 98%; score 3, 86%; score 4, 85%; and score 5, 64%.