TUESDAY, Dec. 18 (HealthDay News) -- Women with HER2-positive breast cancer benefit from treatment with Herceptin regardless of whether or not they have extra copies of chromosome 17, and women with very small HER2-positive or triple negative tumors may also be candidates for such aggressive therapy, according to two studies presented this week at the San Antonio Breast Cancer Symposium.
Monica M. Reinholz, Ph.D., of the Mayo Clinic in Rochester, Minn., and colleagues studied 865 patients who had HER2 amplified tumors with polysomy 17 and 685 patients who had amplification with two normal copies of chromosome 17. They found that five-year disease-free survival was almost identical (88-89 percent) in both groups.
Surabhi Amar, M.D., of the Mayo Clinic in Jacksonville, Fla., and colleagues studied 401 patients with small (one centimeter or less), node-negative breast cancer, including 27 with HER2-positive tumors and 24 with triple negative tumors. They found that more of the HER2-positive and triple negative tumors were grades 2 or 3 (92 percent and 91 percent, respectively) than the HER2-negative and estrogen receptor/progesterone receptor-positive tumors (36 percent). Relapse rates were also significantly higher in patients with HER2-positive and triple negative tumors.
"Should Herceptin be offered to such small node-negative tumors? There is not enough data currently to answer this question," Amar said in a statement. "But this study definitely highlights the fact that HER2-positive tumors, even if very small, may warrant more aggressive therapy."
The Reinholz study was funded in part by Genentech.
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