Neoadjuvant chemotherapy for locally advanced breast cancer results in alterations in preoperative tumor marker status

Abstract

Neoadjuvant therapy followed by breast-conserving surgery has become an acceptable option for patients with locally advanced breast cancer. Although a distinct survival benefit has not been demonstrated using this approach, several questions have been raised following such therapy including its effects on receptor status and tumor markers. The current study retrospectively reviews estrogen receptor (ER), progesterone receptor (PR), and HER2-neu status in 55 consecutive patients treated by neoadjuvant chemotherapy. Preoperative and postoperative tumor markers were available for 43 of the 55 patients (78%). The pathologic complete tumor response rate (pCR) for this group was 19 per cent (8/43). Of those patients who did not achieve a pCR (n = 35), a change in tumor markers was seen in 25.7 per cent (9/35) of patients. When compared to a control group not undergoing neoadjuvant therapy, a significantly higher percent change in marker expression was noted in the neoadjuvant group (25.7% vs 5.9%, P = 0.046). ER, PR, and HER2-neu status remain important prognostic indicators for breast cancer. Tumor markers are useful in planning adjuvant therapy regimens. In this review, nearly 19 per cent of patients achieved a pCR. In patients not achieving a pCR, one in four patients had at least one change in tumor marker status. This study demonstrates the importance of establishing receptor and marker status prior to neoadjuvant therapy, as many patients will achieve a pCR and make tumor analysis impossible. Postoperative marker studies should be performed given the possibility of a change in status. The clinical relevance of this data will require further long-term follow-up. Until such data becomes available, caution should be considered when basing adjuvant therapy regimens on preoperative tumor marker studies alone.