Use of Adjuvant Trastuzumab After Surgery to Reduce Recurrence of Breast Cancer

By: Hope Craig, MSPH
Posted: Monday, May 2, 2022

In a retrospective cohort study published in Scientific Reports, researchers at the University of Saskatchewan, Canada, assessed the outcomes of patients with HER2-positive T1a/bN0 breast cancer who received adjuvant trastuzumab. Shahid Ahmed, MD, and colleagues focused on the impact of postoperative trastuzumab for smaller HER2-positive tumors that had not metastasized and found it to be of potential benefit in reducing the risk of recurrence in younger women with small tumors. “Women who did not receive adjuvant trastuzumab had a fourfold greater risk of recurrence,” Dr. Ahmed noted in an institutional press release.

The study evaluated data from health records of all women diagnosed with HER2-positive T1a/bN0 breast cancer from 2008 to 2017 in Saskatchewan. A total of 91 women who had early-stage, nonmetastasized HER2-positive breast cancers smaller than 10 mm were included. Participants had a median age of 61 years (range, 30–89 years). A total of 39 women (43%) received adjuvant trastuzumab in combination with chemotherapy; they tended to be younger, had higher rates of T1b disease, and had tumors that were mostly larger than 5 mm. A total of 52 women (57%) constituted the control group and did not receive adjuvant trastuzumab.

The median follow-up period for all participants was 70 months. Breast cancer recurrence developed in one woman (3%) in the trastuzumab group compared with six women (12%) in the control group (P = .23). The 5-year disease-free survival of women who received adjuvant trastuzumab was 94.8% compared with 82.7% in the control group (P =.22), and the 5-year overall survival was 100% compared with 90.4% (P = 0.038). Further, multivariate analyses showed grade III tumors correlated with inferior disease-free survival, and the propensity score showed that lack of treatment correlated with inferior disease-free survival.

“The results of this study highlight the need for future phase III clinical trials to further investigate the role of adjuvant trastuzumab along with a non-chemotherapy dual HER2 blockade to minimize toxicity in early-stage T1a and T1b node-negative HER2-positive breast cancer,” the authors commented.

Disclosure: The study authors reported no conflicts of interest.

Scientific Reports

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