Women with early-stage HER2-positve breast cancer are at significant risk of recurrence, according to a study published in the Journal of Clinical Oncology (2009 Nov 2 [Epub ahead of print].
According to the study’s senior author, Ana M. Gonzalez-Angulo, MD, associate professor in M.D. Anderson’s departments of breast medical oncology and systems biology, the analysis of breast cancer patients with tumors 1 centimeter or smaller represents a shift in the way women with early-stage HER2 positive breast cancer should be assessed for risk of recurrence and treatment.
The retrospective study, conducted by Dr Gonzalez-Angulo and her team, analyzed 965 patients treated between 1990 and 2002 and found that more than 10% of this patient population had HER2-positive tumors.
“Our findings show that women with early-stage HER2-positive breast cancer have a 23% chance of recurrence,” said Dr Gonzalez. In contrast, she noted, “the 5-year survival rate of all women with such early-stage breast cancer is more than 90%.” The risk of recurrence was much higher than the researchers expected.
For patients with HER2-positive tumors, the 5-year recurrence-free survival was 77.1% compared to HER2 negative patients’ recurrence-free survival of 93.7%. Patients with HER2-positive tumors had a 2.68 times higher risk of recurrence and a 5.3 times higher risk of distant recurrence than those with HER2-negative tumors.
In addition, women with HER2-positive tumors had 5.09 times the risk of recurrence and 7.81 times risk of distant recurrence than women with hormone receptor-positive tumors.
In the press release announcing the findings, Dr Gonzalez explained that current guidelines call for no additional therapy after surgery and radiation if tumors are less than 5 millimeters and Herceptin-based adjuvant therapy should be discussed with patients if the tumors are from 6 to 10 millimeters.
Dr Gonzalez also added that the number of patients with HER2-positive tumors smaller than 1 centimeter continues to increase as breast cancer surveillance and early detection become increasingly sophisticated.
“With this study we now have concrete evidence to discuss with our HER2-positive patients with even the smallest of tumors, and Herceptin along or combined with chemotherapy should be strongly considered as adjuvant therapy,” said Jennifer Litton, MD, assistant professor in M.D. Anderson department of breast medical oncology, and co-author on the study. “This data should also encourage this subset of patients to be included in ongoing clinical trials with HER2-targeted therapies.