Researchers in the U.S. and Italy report that women with HER2-positive breast cancers that are 1 cm or less in diameter and are node-negative have a risk of recurrence that is two to five times greater than that of women with HER2-negative breast cancers (J Clin Oncol online, November 2, 2009).
Ana M. Gonzalez-Angulo, MD, and colleagues at Houston’s M.D. Anderson Cancer Center reviewed records from 965 women diagnosed between 1990 and 2002. They compared the rates of recurrence and metastasis among women with HER2-positive and HER2-negative breast cancers after a median follow-up of six years.
They found that five years after diagnosis, 77.1% of the HER2-positive patients were free of recurrence and 86.4% were free of metastasis, compared with 93.7% and 97.2% of the HER2-negative patients, respectively. Compared with women who had HER2-negative tumors, women with HER2-positive tumors were 2.68 times more likely to experience a recurrence and 5.3 times more likely to experience metastasis.
In the second study, Giuseppe Curigliano, MD, PhD, and co-authors from the Istituto Europeo di Oncologia in Milan found that women with HER2-positive node-negative breast tumors 1 cm or less in diameter have a 2.4-fold greater risk of recurrence compared to those with HER2-negative disease.
Additionally, women with HER2-positive tumors that also contained receptors for progesterone and/or estrogen had worse disease-free survival than women with hormone-receptor positive, HER2-negative tumors.
They reviewed records from 2,130 women of whom 7% had HER2-positive disease. Researchers examined the risk of recurrence and disease-free survival among women with both HER2-positive and HER2-negative disease, and further stratified patients according to hormone receptor status.
After a median follow-up of 4.6 years, they found that HER2-positive disease was associated with less favorable disease-free survival, regardless of hormone receptor status. Among women with hormone receptor positive disease, five-year disease-free survival was 92% for patients with HER2-positive tumors and 99% for patients with HER2-negative tumors.
The authors of both studies recommended that trastuzumab (Herceptin) should be considered for these patients. Jennifer Obel, MD, a member of the ASCO Cancer Communications Committee, agreed, commenting that trastuzumab is an effective targeted agent in women with these smaller tumors and should be discussed with patients.