177Lu-BetaBart in Patients With Relapsed/Refractory, Locally Advanced Inoperable, or Metastatic Solid Tumors

This study is testing a new radioactive drug called 177Lu-BetaBart for people with various types of advanced solid tumors that have not responded to standard treatments. The drug delivers targeted radiation directly to cancer cells. **You may be eligible if...** - You are 18 or older - You have been diagnosed with one of the following cancers that has come back or spread: prostate cancer, colorectal cancer, non-small cell lung cancer, small cell lung cancer, head and neck cancer, ovarian cancer, cervical cancer, endometrial cancer, triple-negative breast cancer, or esophageal squamous cell cancer - For prostate cancer: your PSA is rising and your cancer is progressing despite hormone therapy - Your cancer is progressing based on blood tests, imaging, or bone scans - You are willing to comply with all study procedures **You may NOT be eligible if...** - Your cancer does not match one of the eligible types - Your organ function (kidneys, liver, blood counts) does not meet study requirements - You are unable or unwilling to follow study procedures Talk to your doctor to see if this trial is right for you.