A single-center study of trastuzumab interruption in patients with ERBB2-positive breast cancer found that dose interruption was associated with higher rates of disease recurrence and death compared with uninterrupted treatment.

Researchers from Memorial Sloan Kettering Cancer Center conducted the study because “findings from the PHARE and PERSEPHONE trials on the noninferiority of 6- vs 12-month durations of trastuzumab are conflicting, thus the clinical significance of early trastuzumab interruption on breast cancer outcomes remains uncertain.”

The study included 1396 patients who had been treated with trastuzumab between 2004 and 2013. Early interruption was defined as a 6-week or longer interval between scheduled trastuzumab doses.

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With a median follow-up of 6 years, breast cancer recurrence or death occurred in 24% of the patients with interrupted treatment and 13% of patients in the uninterrupted group (log rank P <.001; hazard ratio [HR], 1.56; 95% CI, 1.10-2.21).

Findings indicated that the total dose of trastuzumab “plays an important role in breast cancer outcomes.” Trastuzumab interruption with a cumulative dose of 56 mg/kg or less was associated with a reduced recurrence-free survival (adjusted HR, 1.96; 95% CI, 1.16-3.33).

“Given that most patients in this study were treated with anthracyclines, our findings may not be generalizable to patients receiving nonanthracycline treatment regimens,” the researchers noted.


Copeland-Halperin RS, Al-Sadawi M, Patil S, et al. Early trastuzumab interruption and recurrence-free survival in ERBB2-positive breast cancer. JAMA Oncol. Published online October 15, 2020.doi:10.1001/jamaoncol.2020.4749