CHICAGO — One year of trastuzumab continues to be the standard of care for adjuvant treatment among patients with early-stage HER2-positive breast cancer, according to the results of a meta-analysis presented at the ASCO Annual Meeting.
“There are several studies evaluating shorter treatment with trastuzumab (Herceptin, Genentech) compared to [the] standard 1 year of treatment in patients with early-stage HER2-positive breast cancer, but data were inconclusive,” Hadar Goldvaser, MD, staff physician at Rabin Medical Center at the Davidoff Cancer Center in Israel, told HemOnc Today. “Therefore, we wanted to do a meta-analysis to evaluate whether shorter treatment with trastuzumab is appropriate.”
Goldvaser and colleagues performed a search of PubMed and conferences to locate randomized trials that compared shorter durations of trastuzumab therapy with 1 year of treatment in early-stage HER2-positive breast cancer. The meta-analysis included six randomized clinical trials with a total of 11,603 patients that compared abbreviated trastuzumab therapy (9 to 12 weeks and 6 months) with the standard 1 year of treatment. The researchers examined hazard ratios and 95% CIs for DFS and OS.
Median follow-up was 71 months. Adjuvant chemotherapy included anthracyclines and taxanes in the majority of the studies evaluated.
The researchers found that patients treated with a shorter duration of trastuzumab treatment demonstrated worse DFS (HR = 1.14; 95% CI, 1.05-1.25) and OS (HR = 1.15; 95% CI, 1.02-1.29).
Estrogen receptor status (P for the subgroup difference = .23), nodal involvement (P = .44) and the different duration of trastuzumab in the experimental arm (P = .08) did not affect DFS.
There were no differences in outcomes between patients treated with 9 weeks of trastuzumab compared to 6 months, Goldvaser said.
After an estimated median follow-up of 71 months, there was a 2.3% absolute increase in DFS events associated with shorter trastuzumab treatment. Patients treated with a shorter duration of trastuzumab demonstrated lower odds of cardiac dysfunction (OR = 0.67; 95% CI, 0.55-0.81) and congestive heart failure (OR = 0.66; 95% CI, 0.5-0.86).
“This difference was significant,” Goldvaser told HemOnc Today. “If a patient has a high clinical risk for cardiovascular events or is already known to have cardiovascular disease and also has a relatively low clinical benefit, considering shorter treatment may be appropriate in this specific population.” – by Alaina Tedesco
Goldvaser H, et al. Abstract 524. Presented at: ASCO Annual Meeting; May 31-June 4, 2019; Chicago.
Disclosures: Golvaser reports receiving honoraria from Roche. Please see the abstract for a list of all other authors’ relevant financial disclosures.