Gastrointestinal stromal tumorsDownloads

A research team develops a new monoclonal antibody checkpoint inhibitor for advanced melanoma that has shown promise in animal studies as well as high efficacy and low toxicity in early phase human clinical trials. The research team would now like to compare this drug to existing standard of care immunotherapy for advanced melanoma. The research team decides to conduct a non-randomized study where the novel drug will be offered to patients who are deemed to be at risk for toxicity with the current standard of care immunotherapy, while patients without such risk factors will receive the standard treatment. Which of the following best describes the level of evidence that this study can offer?

A 49-year-old male presents to his primary care physician for the first time in twelve years. His chief complaint is a new onset of diarrhea, which nothing seems to improve. He first noticed this diarrhea about a month ago. He complains of greasy stools, which leave a residue in his toilet bowl. Review of systems is notable for alcohol consumption of 12-16 cans of beer per day for the last two decades. Additionally, the patient endorses losing 12 lbs unintentionally over the last month. Vital signs are within normal limits and stable. Exam demonstrates a male who appears older than stated age; abdominal exam is notable for epigastric tenderness to palpation. What is the next step in diagnosis?