Long-term follow-up analysis of the NCCTG N9831 (Alliance) and NRG Oncology/NSABP B-31 trials, reported in the Journal of Clinical Oncology by Chumsri et al, showed poorer recurrence-free survival in hormone receptor (HR)-negative vs HR-positive HER2-positive breast cancer, with the addition of adjuvant trastuzumab to chemotherapy having a similar degree of benefit in both groups of patients.
The analysis included 3,177 patients with HER2-positive breast cancer (1,762 from NCCTG N9831 and 1,415 from NSABP B-31). In the pooled population, 54.5% of patients had HR-positive disease and 48.0% received adjuvant trastuzumab in addition to chemotherapy.
Overall, patients with HR-positive disease had better 10-year recurrence-free survival vs those with HR-negative disease (73.8% vs 69.2%, P < .001); the difference was significant during the first 5 years of follow-up (hazard ratio [HR] = 0.65, P < .001) but not for years 5 to 10 (HR = 1.32, P = .12).
A similar benefit of adjuvant trastuzumab plus chemotherapy vs chemotherapy alone in 10-year recurrence-free survival was observed in both HR-positive disease (81.4% vs 65.2%, HR = 0.46, P < .001) and HR-negative disease (77.8% vs 59.3%, HR = 0.47, P < .001). The benefit of trastuzumab among all patients was significant during the first 5 years of follow-up (HR = 0.42, P < .001) and for years 5 to 10 (HR = 0.69, P = .03).
Overall, a low risk of recurrence was observed in years 5 to 10 among patients with HR-positive disease and no lymph node involvement (3.2%) or involvement of 1 to 3 nodes (6.4%)
The investigators concluded, “The benefit of adjuvant trastuzumab persists for a long time. A distinct pattern of recurrence was observed between HR[-positive] and HR[-negative] HER2[-positive] disease but with similar degree of benefit from adjuvant trastuzumab. [Risk of recurrence] in years 5 to 10 in HR[-positive] HER2[-positive] breast cancer is low, particularly in patients with N0 or N1 disease.”
Saranya Chumsri, MD, of the Division of Hematology and Medical Oncology, Mayo Clinic, Jacksonville, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by National Cancer Institute grants, Genentech, and others. For full disclosures of the study authors, visit jco.ascopubs.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.