Would you use single agent adjuvant HER2 directed therapy for patients with low risk HER2+ breast cancer who are not candidates for chemotherapy?

There are no data regarding single agent trastuzumab as adjuvant therapy, and the existing studies (FinHER, SOLD) suggest that much of the benefit occurs during the chemotherapy phase. The "after chemo" efforts (HERA, N9831) appear inferior. So I would try to incorporate the chemotherapy component, ...