New PET tracer could reveal how well breast cancer treatment works

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patients must have histologically confirmed invasive breast cancer with metastatic disease * Patients must be candidates for treatment with PARP inhibitor as a single agent or for PARP inhibitor in combination with an ICI per treating physician discretion * Patients must have evaluable disease or at least one measurable lesion that can be assessed at baseline by CT (or magnetic resonance imaging \[MRI\]) per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 * Age \>= 18 years * Karnofsky performance status (KPS) \>= 50% or Eastern Cooperative Oncology Group (ECOG) performance status 0-2 * Archival tissue (formalin-fixed paraffin-embedded \[FFPE\]) from at least one metastatic site biopsy should be available prior to study enrollment; if archival tissue is not available, then a metastatic site biopsy will be required during the study screening period * Patient must be willing to proceed with an on-treatment biopsy of metastatic site if an on-treatment \[18F\]FTT PET will be performed (at 12 ± 4 weeks after starting PARP inhibitor ± ICI treatment) * For women of childbearing potential, a negative serum pregnancy test is required within 7 days prior to \[18F\]FTT PET imaging on day 1. For women who obtain on-treatment (12-week) \[18F\]FTT imaging, a negative serum pregnancy test will be required within 7 days prior to \[18F\]FTT PET imaging * Men and women of reproductive potential need to agree to employ two highly effective and acceptable forms of contraception throughout their participation in the study * Patient is willing and able to comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations * Ability to understand and the willingness to sign a written informed consent document. Informed consent must be provided prior to any study specific procedures Exclusion Criteria: * Patients with prior myelodysplastic syndrome or acute myeloid leukemia due to rare risk associated with PARP inhibitor therapy * Pregnant or breastfeeding women * Patient with a known hypersensitivity to the proposed PARP inhibitor product * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements * Patients unable to swallow orally administered medication and patients with gastrointestinal disorders likely to interfere with absorption of PARP inhibitor therapy (per investigator's discretion)