J Clin Oncol 2020 Sep 16
Randomized Controlled Trial of Trastuzumab With or Without Chemotherapy for HER2-Positive Early Breast Cancer in Older Patients.
Abstract
Purpose
Adjuvant trastuzumab monotherapy has not been compared with trastuzumab + chemotherapy. We investigated the relative value of trastuzumab monotherapy for older patients with breast cancer.
Methods
This study was an open-label, randomized controlled study with a treatment selection design in which a noninferiority criterion was predefined. Patients aged 70-80 years with surgically treated human epidermal growth factor receptor 2-positive invasive breast cancer received trastuzumab monotherapy or trastuzumab + chemotherapy. The primary end point was disease-free survival (DFS) with assessment of prespecified hazard ratio (HR), relapse-free survival (RFS), adverse events (AEs), health-related quality of life (HRQoL), and restricted mean survival time (RMST).
Results
The study involved 275 patients (mean age, 73.5 years) who were followed up for a mean of 4.1 years (range, 0.3-8.0 years). The percentages of patients by cancer stage were as follows: I (pT > 0.5 cm), 43.6%; IIA, 41.7%; IIB, 13.5%; and IIIA, 1.1%. Three-year DFS was 89.5% with trastuzumab monotherapy versus 93.8% with trastuzumab + chemotherapy (HR, 1.36; 95% CI, 0.72 to 2.58; P = .51). At 3 years, RMST differed by -0.39 months between arms (95% CI, -1.71 to 0.93; P = .56). Three-year RFS was 92.4% with trastuzumab monotherapy versus 95.3% with trastuzumab + chemotherapy (HR, 1.33; 95% CI, 0.63 to 2.79; P = .53). Common AEs were anorexia (7.4% v 44.3%; P < .0001) and alopecia (2.2% v 71.7%; P < .0001), and grade 3/4 nonhematologic AEs occurred in 11.9% versus 29.8% (P = .0003) for trastuzumab monotherapy versus trastuzumab + chemotherapy, respectively. Clinically meaningful HRQoL deterioration rate showed significant differences at 2 months (31% for trastuzumab monotherapy v 48% for trastuzumab + chemotherapy; P = .016) and at 1 year (19% v 38%; P = .009).
Conclusion
The primary objective of noninferiority for trastuzumab monotherapy was not met. However, the observed loss of survival without chemotherapy was < 1 month at 3 years. Therefore, and in light of the lower toxicity and more favorable HRQoL profile, trastuzumab monotherapy can be considered an adjuvant therapy option for selected older patients.
Related Questions
What adjuvant therapy would you offer an elderly but healthy patient with T2N1 HR+ HER2+ breast cancer who is not willing to receive cytotoxic chemotherapy?
The Japanese RESPECT trial (Sawaki et al., PMID 32936713) compared trastuzumab alone (T) vs chemo+trastuzumab (Ch+T) in patients >=70 and demonstrated a 3 year DFS of 89.5% (T) vs 93.8% (Ch+T) HR 1.31 p=.51. Based on this data, you could discuss adjuvant AI+trastuzumab for 1 year.
What adjuvant systemic therapy would you offer to a healthy elderly woman with a 5mm, node negative, grade 2 HR+HER2+ invasive lobular carcinoma?
Although several studies have clearly indicated a higher risk of recurrence for early stage HER2+ breast cancers, the absolute risk for T1aN0 breast cancers is still quite low. The studies have been limited by small numbers, but there are retrospective series suggesting excellent outcomes without ad...