Small HER2-positive breast Ca needs adjuvant Tx.(GYNECOLOGY)

SAN ANTONIO -- Women with HER2-positive breast cancers 1 cm or less in size have a surprisingly high 23% risk of relapse within 5 years, according to a first-of-its-kind study from the University of Texas M.D. Anderson Cancer Center, Houston.

That's a recurrence rate more than threefold greater than in similarly sized HER2-negative tumors. This new finding indicates that women with small HER2-positive tumors should be considered candidates for adjuvant systemic therapy, which is not now the case, Dr. Ana M. Gonzalez-Angulo said at the San Antonio Breast Cancer Symposium.

The recurrence risk associated with small HER2-positive breast cancers has not been evaluated previously in a large study. Affected women were excluded from the major clinical trials of trastuzumab (Herceptin) in HER2-positive breast cancer. The assumption has been that the recurrence risk is low enough not to warrant routine adjuvant therapy.

Indeed, current National Comprehensive Cancer Network guidelines don't recommend adjuvant systemic therapy for any T1a tumors--that is, those 1-5 mm--and merely suggest discussing treatment with patients who have 6- to 10-mm T1b tumors without specifying what type of treatment should be considered.

"We found there's no difference in risk of these HER2-positive tumors based on a size of 1-5 mm or 6-10 mm," according to Dr. Gonzalez-Angulo, a breast medical oncologist at M.D. Anderson. She presented a retrospective study of 965 patients with T1a or b breast cancers diagnosed at the cancer center. None received adjuvant systemic therapy. Overall, 10% of the women had HER2-positive tumors.

The 5-year recurrence-free survival rate was 77.1% in patients with HER2-positive tumors and 93.7% in those with HER2-negative tumors. The distant ...