Molecular Residual Disease (MRD) Testing in Colorectal Cancer (CRC): Debate Introduction
Video Transcript
Dr Yelena Janjigian: Okay, so I'll start with just a little bit of an overview. And then, we'll jump to the meat of the talk. So, as I mentioned, you know, I think the most tried and true sort of approach to MRD testing is for early or metastatic stage IV disease. And colon cancer has been in the forefront but certainly other oncogene-driven tumors like lung cancer. And today, you know, today, where there is a mix of tumors. As Chair of GI Great Debates, we've merged with lung and other diseases. So, use this opportunity to cross-pollinate and learn a little bit about solid tumors in general. But, you know, tumor-informed platforms has really been the best option to treat this, track this MRD disease. Because in our population of elderly patients who have been on chemotherapy for—and/or radiation and may have other CHIP or sort of chromosomal instability is an issue. So, often, if we do a nontumor-informed assay, you may pick up alterations in the white blood cells or other circulating cells that are not cancer related. So, it's important to know all of that as you're informing your patients. There's also plasma-only platforms, colorectal cancer-specific assays, and other multi-tumor screening assays, especially for high-risk populations. You know, typically, historically, we've done this for mutations. For disease that I treat the most, which is upper GI tumors, amplifications, and other alterations can be a challenge, especially depending on the platform you use. So, clinical applications—of course, unfortunately, a lot of the data is coming outside of US for prospective studies, and you'll hear today about the Japanese data. And then, there's also going to be more data coming out of Europe and randomized studies in the United States because patients like to do what they like to do. MRD studies are—I can tell you from first experience, because we started an MRD study in 2018, and only now are we publishing it, and that was a pretty small cohort. So, but there's randomized prospective studies coming mostly for direction of stage IV NED patients, resected patients, but also from adjuvant setting in resected disease. And, you know, others may use this to monitor for treatment-refractory disease. But, you know, those approaches are a little, I think, not primetime yet. Because there's only so many chemos you have, and I don't know if switching them before radiographic progression is really—makes a lot of sense in stage IV disease. So, I'll leave you with a case and use this as a springboard for discussion maybe for our speakers. It's not an atypical case because young onset colorectal cancer is so prevalent. And increasingly, I see patients that are closer to my kids’ age than my age. And so, this is a 45-year-old woman. A violinist, so fine motor movement is very important. That's why I put violinist in. With T4N0 tumor resected colorectal cancer, transverse colon mass, negative margins. And she does have high-risk features with lymphovascular invasion, MSI high tumor. And you screened her with tumor-matched assay, and she was found to be negative. Of course, ctDNA is great because the half-life is so short. You know, it's a good way to monitor these patients. She has a busy schedule. She's on tour. She has three kids. And she doesn't want chemotherapy—or if you're going to make her do something, she doesn't want impact in her lifestyle. So, it's actually a guy. But anyway—I thought it was a woman.
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