Evaluation of the MD Anderson Prognostic Index for local-regional recurrence after breast conserving therapy in patients receiving neoadjuvant chemotherapy.

Background: We previously developed a prognostic index for assessing local-regional recurrence (LRR) risk in patients undergoing breast conservation therapy (BCT) after neoadjuvant chemotherapy. The prognostic index assigns a point for each of the following variables: clinical N2/N3 disease, lymphovascular invasion, residual pathologic tumor size >2 cm, and multifocal residual disease on pathology. The current study was undertaken to evaluate this prognostic index in an independent cohort.

Methods: We identified 551 patients treated from 2001 to 2005 with neoadjuvant chemotherapy, mastectomy or BCT, and radiation. These patients were not used in the original development of the prognostic index. Outcomes were stratified by prognostic index. The 5-year LRR-free survival was calculated using the Kaplan-Meier method, and differences were compared using the log-rank test.

Results: For patients undergoing BCT, the 5-year LRR-free survival rates were 92, 92, 84, and 69% when the prognostic index was 0 (n = 91), 1 (n = 82), 2 (n = 38), or 3-4 (n = 13) (P = 0.01). The 5-year LRR-free survival rates were similar between patients undergoing mastectomy or BCT when the prognostic index score was 0, 1, or 2. When the prognostic index score was 3-4, the 5-year LRR-free survival was significantly lower for patients treated with BCT compared with mastectomy (69 vs. 93%, P = 0.007).

Conclusion: The previously developed prognostic index was successful in stratifying patients with respect to LRR in an independent cohort undergoing BCT after neoadjuvant chemotherapy. The prognostic index can be used to identify patients at high risk for LRR who may be considered for more extensive surgery or enrollment into clinical trials evaluating novel strategies for local-regional control.