Memorial Sloan Kettering Cancer Center
The purpose of this study is to find out whether it is safe to skip (omit) radiation therapy to the breast after lumpectomy in people with low-risk HER2-positive breast cancer who are receiving HER2-targeted therapy.
Inclusion Criteria: A patient cannot be considered eligible for this study unless ALL of the following conditions are met. Please contact the study PI for exceptions, or if uncertainties arise. * The trial is open to female and male patients who have undergone breast conserving surgery and have received neoadjuvant\* or adjuvant systemic therapy with a HER2-targeted therapeutic regimen. * The maximum window between surgery (neoadjuvant cohort) or last chemotherapy (adjuvant cohort) and enrollment is 90 days. * While the standard duration of neoadjuvant or adjuvant systemic therapy is at leas…
Participants will continue to receive standard HER2-targeted therapy as part of their usual care
If participants' cancer is hormone receptor-positive, participants may also receive endocrine therapy as part of their usual care.
Participants will not receive radiation therapy to their breast after their lumpectomy.