Preoperative chemotherapy treatment of breast cancer--a review.

Despite proven benefits of neoadjuvant chemotherapy in patients with locally advanced, invasive breast cancer, no regimen is recommended as the treatment of choice. Neoadjuvant chemotherapy regimens encompass single-agent and combination therapy and sequential treatment. For this report, the author reviewed the literature to determine which regimen, if any, was most beneficial. The results indicated that studies have yielded a wide range of response rates, but no single regimen has emerged as a clear leader. The literature is compounded further by lack of standardized criteria to determine pathologic complete response (which is predictive of survival benefits) and between-study variation in the stringency by which this endpoint is defined. Given the lack of a preferred treatment regimen in the neoadjuvant setting, identifying patients who are likely to respond to specific agents could inform treatment decisions, improve treatment outcomes, and aid in avoiding unnecessary exposure to potential toxicities. The development of novel agents for use alone or in combination with existing agents may improve response rates further in the neoadjuvant setting, especially because a significant proportion of breast tumors can be resistant to many current antineoplastic agents. Particularly noteworthy are the epothilones and their analogs because of their low susceptibility to common tumor-resistance mechanisms. Initial data have indicated that ixabepilone, which is an epothilone analog, has activity in the neoadjuvant setting, and predictive factors for response have been identified. The future of neoadjuvant therapy lies in tailoring treatment to individual patients by identifying response predictors and developing novel agents. This ultimately may lead to improved outcomes for women with breast cancer. Copyright (c) 2007 American Cancer Society.