SAN FRANCISCO—Clinical trials have shown significant improvements in disease-free survival when trastuzumab(Drug information on trastuzumab) (Herceptin) is added to standard adjuvant chemotherapy in HER2-positive breast cancer patients, but is it appropriate for all such patients, specifically low-risk patients with tumors 1 cm or smaller in size?

In a pro/con presentation at the 3rd Oncology Congress, Peter Ravdin, MD, PhD, researcher professor in biostatistics at M.D. Anderson Cancer Center, answered no to that question, maintaining that the risk-to-benefit ratio for trastuzumab is too low for such good-prognosis patients.

Taking the pro side, Edith Perez, MD, of the Mayo Clinic, Jacksonville, Florida, acknowledged that more data are needed on patients with HER2-positive tumors under 1 cm. While trastuzumab is not routinely recommended for these patients, she indicated that selected patients may benefit. "The problem is that before we didn't recommend anything for these patients," she said, "and now some are getting chemotherapy and trastuzumab."

Updated results of N9831/B-31

Two years ago at ASCO, findings from the joint analysis of N9831/B-31 were presented to a standing ovation. Updated results, presented by Dr. Perez at ASCO 2007, showed that the benefit of trastuzumab was clearly maintained.

Median 4-year DFS was 86% in the AC-T plus trastuzumab patients vs 73% for AC-T alone (HR 0.48, P < .00001). Risk of death was significantly decreased at 4 years by 35% (P = .0007), despite the fact that 21% of patients randomized to AC-T received trastuzumab after the trial was unblinded.

Trastuzumab improved DFS across the board in subgroup analyses by age, node status, hormone-receptor status, tumor size, and tumor grade, Dr. Perez said.