In what situations would you offer systemic therapy for HER2+ microinvasive invasive ductal carcinoma?  

I usually do not treat microinvasive HER2+ ductal cancer as most screen-detected cases still have a good prognosis and there is limited data for therapy benefit. A review by Padmore et al. (PMID 10717623) and a Chinese series (Si et al. Front Oncol 2020) suggested a higher risk of recurrence in youn...