The Genetic Test Every Patient Should Have Before 5-FU Chemotherapy | Dr. Gabe Brooks
Sep 30, 2026 · 31 min · 11 segments
Two of the most widely used chemotherapy drugs in the world, 5-FU and capecitabine, have been in use since the 1950s. A small share of patients carry variants in a gene called DPYD that slow their…
Two of the most widely used chemotherapy drugs in the world, 5-FU and capecitabine, have been in use since the 1950s. A small share of patients carry variants in a gene called DPYD that slow their ability to break these drugs down, which means a standard dose behaves like an overdose in their body. A single genetic test can identify those patients before the first treatment. Europe recommended universal screening in 2020. The FDA updated the labels for both drugs in 2025, after years of pressure from families who had lost someone.In this episode of Patient From Hell, host Samira Daswani speaks with Dr. Gabe Brooks, a medical oncologist at the Dartmouth Cancer Center, about what DPD deficiency is, what severe toxicity actually looks like, how and when to get screened, what the test costs, and the exact question to ask before starting either drug. Guest: Gabriel Brooks, MD, MPH, is a medical oncologist and Associate Professor of Medicine at the Dartmouth Cancer Center and the Geisel School of Medicine. He co-directs the Cancer Population Sciences Research Program and specializes in gastrointestinal cancers, including colorectal cancer. Chapters 00:00 Introduction 00:27 What DPYD is and why it matters 02:50 When toxicity turns fatal 04:21 5-FU vs. capecitabine 06:16 Which cancers use these drugs 06:53 What the FDA changed 08:26 Why the U.S. took five years longer than Europe 11:27 Warning signs and time to onset 15:28 How and when to get screened 17:39 Germline DNA vs. tumor genomic testing 20:16 The patient advocacy behind the change 24:44 What to ask your oncologist 26:43 What the test costs 28:18 Closing thoughts Resources: Advocates for Universal DPD/DPYD Testing — test4dpd.org🎙️ Patient From Hell is hosted by Samira Daswani, cancer survivor, entrepreneur, and founder of Manta Cares. Through candid conversations with patients, physicians, researchers, and healthcare leaders, the show explores the realities of cancer care while empowering patients with practical, evidence-based information. 🔗 Connect with Patient From Hell Website: https://www.mantacares.com Disclaimer This podcast is intended for educational and informational purposes only and should not be considered medical advice. Always consult a qualified healthcare professional regarding diagnosis, treatment, or medical decisions.
Two of the most widely used chemotherapy drugs in the world, 5-FU and capecitabine, have been in use since the 1950s. A small share of patients carry variants in a gene called DPYD that slow their…
