Using FDG-PET/CT to Assess Response of Bone-Dominant Metastatic Breast Cancer, FEATURE Study

Inclusion Criteria:

Patients must have an Eastern Cooperative Oncology Group (ECOG) performance (performance status [PS]) =< 2
Patients with histologically confirmed metastatic breast cancer by local assessment that is hormone receptor positive by American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines and with known HER2 status

Patients must have radiologically confirmed bone-dominant (BD) or bone-only (BO) disease

BD defined as disease involving bone with or without limited measurable metastases by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, with >= 1 non-irradiated bone metastasis on bone scintigraphy

NOTE: Limited measurable metastases includes lymph nodes and the soft tissue components of lytic or mixed lytic/blastic bone metastases. Any number of lymph nodes < 3 cm and up to 2 lymph nodes > 3 cm will be allowed. Up to 5 measurable soft tissue components of lytic or mixed mytic/blastic bone metastases will be allowed
BO defined as detectable disease confined within the bone (any site, any number of lesions). Diagnosis requires abnormalities identified by imaging (bone scan, CT +/- PET +/- magnetic resonance imaging [MRI]) with no other sites of metastases identified and with >= 1 non-irradiated bone metastasis on bone scintigraphy
Patients must have no contraindication to FDG-PET imaging

Patients must have one of the following systemic therapies:

Plan to receive either 1st or 2nd line endocrine therapy for metastatic breast cancer. Endocrine therapy may include selective estrogen receptor modulators (SERMs), aromatase inhibitors, and/or fulvestrant that may be combined with Food and Drug Administration (FDA)-approved biologic agents (palbociclib, ribociclib, abemaciclib, everolimus, alpelisib)
Chemotherapy per National Comprehensive Cancer Network (NCCN) or institutional standard. Use of colony stimulating growth factor must be suspended for >= 14 days prior to FDG-PET/CT scans at baseline and 12-weeks
Plan to receive HER2-targeted therapy per ASCO, NCCN, and/or institutional guidelines as indicated for patients with HER2 positive disease. When HER2-targeted therapy is used with chemotherapy, use of colony stimulating growth factors is NOT expected or should be suspended for a minimum of 2 weeks, but preferably for at least 3 weeks prior to the required FDG-PET/CT scan time points
The use of bone-stabilizing agents (bisphosphonates or denosumab) is permitted
Patient must meet institutional guidelines for renal function for MRI and CT scanning
Patient's life expectancy must be estimated at >= 24 weeks
The patient is participating in the trial at an institution which has agreed to perform the imaging research studies, completed the ECOG-American College of Radiology Imaging Network (ACRIN) defined PET/CT scanner qualification procedures and received ECOG-ACRIN PET/CT scanner approval

Patients must complete the baseline (T0) FDG-PET within 28 days prior to registration or within 28 days after registration

For patients completing the baseline (T0) FDG-PET AFTER registration all parameters must be met

For patients who completed the baseline (T0) FDG-PET prior to registration the following tests are exempt:

Pregnancy testing documentation prior to FDG-PET (T0 time point)

Exclusion Criteria:

Patients with RECIST 1.1 measurable lesions in viscera, active central nervous system (CNS), leptomeningeal carcinomatous or pleural or peritoneal disease will not be eligible. Patients with prior CNS metastases treated with radiation or resection and without evidence of clinical or radiographic progression within 28 days of registration are eligible
Patients who have received greater than 3 lines of cytotoxic chemotherapy for metastatic breast cancer are not eligible
Patients currently participating in or have participated in a study of an investigational agent or using an investigational device within 3 weeks of study registration are not eligible
Patients with known additional malignancy that is progressing or requires active treatment are not eligible. Exceptions include basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or in situ cervical cancer that has undergone potentially curative therapy
Women must not be pregnant because FDG is a radiopharmaceutical with the potential for teratogenic effects and PET/CT involves additional radiation exposure. In addition, because of radiation exposure to a nursing infant from FDG, women who are breastfeeding are also excluded from this study. All females of childbearing potential must have a blood test or urine study within 7 days prior to FDG-PET/CT to rule out pregnancy. Patients are excluded from this if baseline FDG-PET/CT scan met study parameters and was completed within 28 days of study registration