Pathological complete response in breast cancer patients following neoadjuvant chemotherapy at a Comprehensive Cancer Center: The natural history of an elusive prognosticator.

Given the prognostic significance of pathological complete response (pCR) to neoadjuvant chemotherapy, we sought to chronicle the clinical course of breast cancer patients whose tumors exhibited pCR at our institution. We retrospectively reviewed 5,533 cancer center patients treated for a first primary breast cancer between March, 1999 and September, 2010 to identify those who received neoadjuvant chemotherapy that resulted in pCR (i.e., no residual invasive malignancy in the breast or axilla). The descriptive statistics of treatments received, recurrence, morbidity and mortality as of October, 2013 were reported. Of the 5,533 patients reviewed, 86 met the inclusion criteria. The mean age at diagnosis was 48 years [standard deviation (SD), 9.4 years] and the mean length of follow-up was 68 months (SD, 27 months). The majority of the patients underwent axillary lymph node dissection (ALND; n=60, 69.8%), received adjuvant radiation therapy (XRT; n=72, 83.7%), had poorly differentiated (grade 3) tumors (n=74, 86.1%) and had pure ductal histology (n=74, 86.1%). A total of 5 patients (5.8%) developed disease recurrence. All the patients who recurred had grade 3 tumors with ductal histology and underwent ALND for known pre-neoadjuvant-treatment lymph node metastases; none received adjuvant chemotherapy. A total of 4 patients (4.7%) succumbed to the disease, 3 due to breast cancer recurrence <18 months following the initial diagnosis. Recurrence following pCR was rare, but when it did occur, time- to-recurrence was short at <18 months. All the patients who recurred and eventually succumbed to breast cancer had axillary metastases at diagnosis, indicating that axillary disease is a major negative prognostic factor in patients who achieve pCR following neoadjuvant chemotherapy.