Patient Profile: A 55-Year-Old With Colon Cancer
Experts on colorectal cancer present a patient case, offer their initial impressions, and discuss disease staging.
Transcript:
Tanios S. Bekaii-Saab, MD: Welcome to this Cancer Network® program, “ctDNA Analysis to Direct Treatment Decisions in Colorectal Cancer.” I’m your host, Dr Tanios Bekaii-Saab. I’m a GI [gastrointestinal] medical oncologist and a professor at the Mayo Clinic, and I practice in Phoenix, Arizona. I’m joined by 3 fantastic colleagues and friends. I’ll ask them to introduce themselves. I’m going to start with Dr Ahn.
Daniel H. Ahn, DO: Hi, I’m Daniel Ahn. I’m also a GI medical oncologist at the Mayo Clinic in Arizona.
Tanios S. Bekaii-Saab, MD: Dr Hubbard?
Joleen Hubbard, MD: Hi, I’m Joleen Hubbard. I’m a GI medical oncologist at the Mayo Clinic in Rochester, Minnesota.
Tanios S. Bekaii-Saab, MD: Finally, Dr Parikh.
Aparna Parikh, MD, MS: Hi, I’m Dr Aparna Parikh. I’m a GI medical oncologist at Mass General Cancer Center in Boston, Massachusetts.
Tanios S. Bekaii-Saab, MD: Today we’re going to discuss decision tools that aid in the management of colorectal cancers. We’ll discuss traditional techniques, consider the use of minimal residual disease [MRD] and circulating tumor DNA [ctDNA], and assess clinical trials in these settings. Let’s present the first case, a 55-year-old woman who is diagnosed with adenocarcinoma of the sigmoid following a routine screening colonoscopy. The patient was found not to have metastatic disease. By standard staging, she underwent surgical resection and ended up with a T3 N0 sigmoid colon cancer. The cancer was found to be microsatellite stable, and there was no evidence of lymphovascular or perineural invasion. At that time, the decision was to proceed with an MRD assessment with a ctDNA test, which found no evidence of positive, so it was MRD negative.
Aparna, I’m going to start with you. Looking at this case and thinking about similar cases in your practice, is there anything different that you would have done? Would you, specifically in the MRD assessment, consider this as a standard practice?
Aparna Parikh, MD, MS: This is a typical scenario, a patient with stage II colon cancer. We got some of the details about risk features for this patient in terms of being a T3 tumor with no LVI [lymphovascular invasion] or PNI [perineural invasion]. We didn’t hear about how many lymph nodes were sampled and to ensure the patient had at least 12 lymph nodes. Presumably there was no perforation. Assuming all those things were aligned with this patient being a patient with low-risk stage II colon cancer, this is the rare scenario where I’ve been, as part of my routine care, in the absence of a clinical trial. We don’t have the COBRA trial, which is a lower stage II trial open in Boston. Though these patients generally do well, and you wouldn’t be offering adjuvant chemotherapy in the rare scenario where these patients have a positive test, it’s a scenario that raises the question of giving adjuvant chemotherapy. This is the perfect example of a case where you’re not planning on giving chemotherapy. An MRD test may persuade you to give therapy if it happened to be positive.
Tanios S. Bekaii-Saab, MD: You bring up a great point about the lymph nodes. This patient had 14 lymph nodes removed, and they were all negative. If it was less than 12, then you’d consider a different approach.
Dan, guide us through a patient who was found to have a mass on a colonoscopy such as the one we presented. What staging do you want, and then what next?
Daniel H. Ahn, DO: Typically when patients undergo surveillance colonoscopies or a colonoscopy because they present with symptoms, we perform to get a biopsy to confirm the histology. In this case, we’re talking about adenocarcinoma, which is what we typically see in colon cancer. At that time, we’d typically perform staging imaging—a complete CT scan of the chest and then an MRI or a CT scan of the abdomen and pelvis—to ensure the patient doesn’t have a more advanced disease. If the patient continues to have evidence of localized disease, we’d recommend that they proceed with surgical resection. There aren’t any data to support neoadjuvant treatment, like in rectal cancer. The 1 study that was presented unfortunately didn’t show any disease-free survival benefit. That was the NeoCol study. The recommendation for patients who are optimal surgical candidates is that they undergo up-front surgical resection. After that, they’d be sent to the medical oncologist to discuss the pathology findings and the potential need for further treatment—in this case, adjuvant chemotherapy.
Tanios S. Bekaii-Saab, MD: Great, thank you.
Transcript edited for clarity.
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