Using 18F-FFNP PET/CT and Minimally Invasive Biomarkers to Detect Treatment Resistance in Advanced or Metastatic Lobular Breast Cancer
This phase II trial studies how well an imaging scan called fluorine F 18 fluoro furanyl norprogesterone (FFNP) positron emission tomography (PET)/computed tomography (CT) and two blood-based tests, circulating tumor cells (CTCs) and circulating tumor deoxyribonucleic acid (ctDNA), works to identify treatment resistance to anti-estrogen treatment in patients with lobular breast cancer (LBC) that that may have spread from where it first started to nearby tissue, lymph nodes, or distant parts of the body(advanced) or that has spread from where it first started (primary site) to other places in the body (metastatic). 18F-FFNP is a radioactive solution that has a similar chemical structure to the body’s own progesterone, and does not have any hormonal treatment effects on the body. A PET scan takes pictures of the inside of the body. A very small amount of radioactive imaging tracer (in this trial, 18F-FFNP) is injected through a needle in the arm and travels through the entire body. PET images are made when the scanner detects where the radioactive tracer travels in the body. CT scan is a procedure that uses a computer linked to an x-ray machine to make a series of detailed pictures of areas inside the body. The pictures are taken from different angles and are used to create 3-dimensional (3-D) views of tissues and organs. The two blood-based tests, circulating tumor cells, or CTCs for short, and circulating tumor DNA, or ctDNA for short, are called biomarkers. A biomarker is a measurable indicator of the severity or presence of some disease state, in this case cancer. CTCs are cancer cells that shed from primary and metastatic cancers into the blood in patients with cancer. Sensitive detection of CTCs from blood samples can serve as an effective tool in understanding and predicting how a cancer will behave. ctDNA are small pieces of DNA that are released into a person’s blood by cancer cells as they die. A sample of blood can be used to look for and measure the amount of ctDNA and identify specific mutations (changes) in the DNA. ctDNA is being used as a biomarker to help diagnose some types of cancer, to help plan treatment, or to find out how well treatment is working or if cancer has come back. Using 18F-FFNP PET/CT and minimally invasive biomarkers may help to predict whether a cancer is sensitive to anti-estrogen treatment, a standard type of medication used to treat metastatic lobular breast cancer in patients with advanced or metastatic lobular breast cancer.