Preliminary results of centralized HER2 testing in ductal carcinoma in situ (DCIS): NSABP B-43.
NSABP B-43 is the first prospective, randomized phase III multi-institution clinical trial targeting high-risk, HER2-positive DCIS. It compares whole breast irradiation alone with WBI given concurrently with trastuzumab in women with HER2-positive DCIS treated by lumpectomy. The primary aim is to determine if trastuzumab plus radiation will reduce in-breast tumor recurrence. HER2-positive DCIS was previously estimated at >50 %, occurring primarily in ER-negative, comedo-type DCIS of high nuclear grade. There has been no documented centralized multi-institutional HER2 analysis of DCIS. NSABP B-43 provides a unique opportunity to evaluate this in a large cohort of DCIS patients. Patients undergoing lumpectomy for DCIS without evidence of an invasive component are eligible. A central review of each patient's pure DCIS lesion is carried out by immunohistochemistry analysis. If the lesion is 2+, FISH analysis is performed. Patients whose tumors are HER2 3+ or FISH-positive are randomly assigned to receive two doses of trastuzumab during WBI or WBI alone. NSABP B-43 opened 11/9/08. As of 7/31/2013, 5,861 patients have had specimens received centrally, and 5,645 of those had analyzable blocks; 1,969 (34.9 %) were HER2 positive. A total of 1,428 patients have been accrued, 1,137 (79.6 %) of whom have follow-up information. The average follow-up time for the 1,137 patients is 23.3 months. No grade 4 or 5 toxicity has been observed. In NSABP B-43 the HER2-positive rate for pure DCIS among patients undergoing breast-preserving surgery is 34.9 %, lower than the previously reported rate. No trastuzumab-related safety signals have been observed. Interest in this trial has been robust.
Breast cancer research and treatment
Siziopikou, K., Anderson, S., Cobleigh, M., Julian, T., Arthur, D., Zheng, P., Mamounas, E., Pajon, E., Behrens, R., Eakle, J., Leasure, N., Atkins, J., Polikoff, J., Seay, T., McCaskill-Stevens, W., Rabinovitch, R., Costantino, J., & Wolmark, N. (2013). Preliminary results of centralized HER2 testing in ductal carcinoma in situ (DCIS): NSABP B-43.. Breast cancer research and treatment, 142 (2), 415-421. Retrieved from https://scholarcommons.towerhealth.org/hema_oncol_read/21