Some women with small breast tumors may have a greater risk of the cancer recurring after treatment than has been believed, and might benefit from taking the drug Herceptin, a new study suggests.
Treatments like chemotherapy or Herceptin are not usually recommended for women whose tumors are smaller than 1 centimeter — just under half an inch — and have not spread beyond the breast.
However, Texas researchers who looked at records on 1,315 such patients found that the 10 percent who had high levels of a protein called HER-2 had three times the risk of suffering a recurrence than did women with less HER-2.
Only 77 percent of those with high HER-2 levels were alive and cancer-free five years after treatment versus 94 percent of the others.
Women in the study had been treated at the University of Texas M.D. Anderson Cancer Center in Houston or at two European hospitals in the 1990s.
HER-2 has long been known to predict aggressiveness of tumors. But it has been considered less important than other factors like the size of a tumor or whether it is being helped to grow by estrogen.
The new findings may lead doctors to rethink HER-2's importance and whether to more widely recommend Herceptin, which helps block the protein, said the study's leader, Dr. Ana Gonzalez-Angulo of M.D. Anderson.
She reported results Friday at the San Antonio Breast Cancer Symposium. She has no financial ties to Herceptin's maker, California-based Genentech Inc., but some of her co-authors do.
The findings need to be tested in larger studies to see if women with small HER-2 tumors really are at greater risk, said Dr. Powel Brown of Baylor College of Medicine.
"The implication would be that they might benefit from treatment," but that wasn't tested in the Texas study, said Brown, who has no ties to Genentech.