Neoadjuvant induction chemotherapy.

Abstract

Neoadjuvant chemotherapy (NACT) and neoadjuvant hormonal therapy (NAHT) have been adopted worldwide as appropriate, if not standard of care, options of treatment for patients with locally advanced carcinoma of the breast. The initial role of NACT was the conversion of so called inoperable tumors into those for which mastectomy could now be performed, irrespective of effect on overall survival outcome. As breast conservation became accepted as an alternative to mastectomy in selected patients, NACT often reduced tumor volume enough to allow consideration of this option for these patients as well. Currently a majority of patients undergoing NACT become candidates for breast conservation. Clinical trial data, however, suggest that overall survival has not been affected by NACT, although recent non randomized but prospective data do document improved disease free and overall survival, as well as decrease in local recurrence. The adoption of axillary lymphatic mapping and sentinel lymph node biopsy (SLNB) in stage I/II, clinically N0 patients has promoted the judicious use of SLNB in selected patients who have undergone NACT, if the nodes are ''downstaged'' and are clinically negative at the completion of NACT. SLNB in these patients remains highly controversial, as does the application of NACT in patients with smaller (T1, N1, or T2, N01) cancers. The optimal choice of drug regimens for NACT is also controversial, i.e., both the drugs used and the duration of treatment. Generally accepted approaches are usually the same as if the drugs were given as adjuvant, rather than neoadjuvant, treatment. Most investigators do agree that those patients who achieve a complete pathological response (pCR, or absence of any invasive cancer in the final specimen) to NACT do have an improved outcome, so that the manipulation of treatment regimens by ongoing clinical trials is of utmost importance in this regard. The recent observation of an increased rate of pCR in patients with Herceptin added to the NACT regimen is, therefore, an exciting advance and requires further investigation. The adoption of NACT into treatment plans for women with earlier cancers is likely to become even more ubiquitous if a higher likelihood of pCR can be achieved, and as more and more women with smaller tumors (T1c) become almost automatic candidates for adjuvant chemotherapy because of tumor size, irrespective of node status. It is not difficult to imagine that the majority of women with breast cancer will become candidates for NACT as more information about tumor response and outcome data are accumulated.