Prospective clinical experience with research biopsies in breast cancer patients.

There are ethical concerns regarding the performance of biopsies in patients for research purposes. We examined our single-institution experience regarding acceptance, safety, and success rate with research biopsies in patients with breast cancer. Among patients with data from paired samples, receptor status agreement between primary and metastatic samples was examined, either on first recurrence or after progression on one or more lines of therapy. An IRB-approved prospective study at the Dana-Farber Cancer Institute collects research biopsies as additional passes at the time of a clinical biopsy (AB, additional biopsy) or as a separate procedure for banking purposes (RPOB, research purposes only biopsy). Biopsies are not linked to a specific therapeutic or correlative trial. Grade 2-5 adverse events are prospectively collected. 151 patients were included in the analytic cohort (total procedures = 161); 80.8 % underwent AB, 17.2 % underwent RPOB, and 2.0 % underwent both AB and RPOB. Most patients were white (88.7 %) with a performance status of 0-1 (94.0 %). 96.0 % of patients underwent a biopsy in the setting of known or suspected metastatic disease. Receptor status between primary cancer and recurrent research biopsies differed in 43.2 % of patients with available data (18.8 % among patients who underwent the research biopsy before any systemic treatment, 48.1 % after treatment). Tissue was successfully collected in 92.3 % of patients undergoing AB and 100 % patients undergoing RPOB. Only three (2.0 %) patients had adverse events ≥ grade-2: one grade-2 pain; one grade-2 pneumothorax; and one grade-3 pain. Our experience suggests research biopsies can be performed safely with a high rate of successful tissue collection. Consistent with previous reports we found a high rate of discordance between primary and metastatic samples, which was even higher among treated patients. This supports continued efforts to study tissue samples at multiple points in a patient's disease course.