Impact of preoperative versus postoperative chemotherapy on the extent and number of surgical procedures in patients treated in randomized clinical trials for breast cancer

Objective: To determine the effect of preoperative chemotherapy on the volume of tissue excised and the number of breast operations in patients undergoing breast-conserving therapy (BCT). Summary Background Data: Preoperative chemotherapy is increasingly being used for breast cancer and increases rates of BCT. Its impact on the extent of surgery and the number of surgical procedures in BCT has never been fully defined. The extent of surgery in BCT directly affects cosmesis. Methods: We reviewed the records of 509 consecutive patients with T1-T3, N0-N2 breast cancer who were treated in prospective randomized clinical trials of chemotherapy between 1998 and 2005. We analyzed the final surgical procedure (BCT or mastectomy), the number of operations, and, in patients who underwent BCT, re-excision rates, and the total volume of breast tissue excised [4 Pi/3(width/2 X length/2 X height/2)]. Results: A total of 241 patients underwent BCT, and 268 patients underwent mastectomy. Among BCT patients who had initial tumor size >2.0 cm, patients who received preoperative chemotherapy had significantly smaller volumes of breast tissue excised compared with patients who received postoperative chemotherapy (113 cm(3) vs. 213 cm(3), P = 0.004). The re-excision rate and total number of breast operations did not significantly differ between the groups. Among BCT patients who had initial tumor size <= 2 cm, preoperative chemotherapy had no impact on volume of breast tissue excised, re-excision rate, or number of breast operations (P > 0.05). Conclusions: Among patients treated with BCT for larger breast tumors, patients treated with preoperative chemotherapy have less extensive resection, with no change in rates of re-excision.