What tests are involved in gastric cancer diagnosis and staging? Dr. Yelena Janjigian explains key testing and considerations that are used to determine gastric cancer staging for optimal care.
Dr. Yelena Janjigian is Chief of Gastrointestinal Oncology Service at Memorial Sloan Kettering Cancer Center.
Could you tell us what tests are used to diagnose gastric cancer?
Most of our patients, when they come in to see me, by then the diagnosis of cancer has been made because I’m on oncologist.
In clinical practice, patients often present with vague symptoms or no symptoms at all. And that’s an important point for our clinicians to understand. In patients who have chronic acid reflux or have, for example, other risk factors such as H. pylori infection, often they end up getting endoscopy at the time, for example, for their first colonoscopy. So, the age of colonoscopy, the first colonoscopy has is getting earlier and earlier with each update, because colon cancer is increasing in incidents in younger adults.
So, sometimes patients present and get first endoscopy, for example, which is an upper test with a camera when they’re getting their colonoscopies. In other patients, unfortunately, they present with more progressive symptoms. Often, it’s difficulty swallowing, regurgitation of food, and weight loss, which is obviously very dramatic.
And so they end up getting an endoscopy because of that and referred by their doctors.
How is gastric cancer staged? And what do the stages mean?
Yeah. So, the most important part of the staging of gastric cancer and what patients ask me, “What is my risk of cancerous recurrence? What is my stage?” Really what it comes down to is the depth of invasion. So, it’s not only the size of the tumor, but how deep is it going into the muscle of the stomach, because stomach and your esophagus are basically a muscular bag, right? And so how deep is the invasion of the tumor into the wall? And also how likely are the lymph nodes to being involved?
So, we assess it based on clinical symptoms such as swallowing difficulty and so forth. But in some patients, because the tumor is lower down in their stomach, they may not have very many symptoms, because there’s a lot more give in this muscular bag that our stomach is.
And so we test the endoscopic ultrasound to look at the depth of an invasion and also other X-ray type imaging such as a PET scan, a P-E-T scan or a CAT scan, which gives us a sense of tumor location whether or not we think the lymph nodes may be involved. And ultimately the final way to assess, especially in patients who are undergoing surgery, is their microscopic involvement of the lymph nodes? Because that often drives the likelihood of cancer coming back after surgery.
And how do the stages work for gastric cancer?
So, in gastric cancer it’s either early, intermediate, or late stage. And this goes from stage I to IV. So, stage IV tumors is where most of the cancers are present. Over probably 50 percent of our patients present already at the time of diagnosis with more advanced stages.
Biologically this cancer just tends to move quickly. So, even in between endoscopies in patients who get endoscopies frequently, often it goes from 0 to stage III or IV because of the lymph node involvement and also spread of microscopic cells, right? Tiny, tiny cells before we even see them, they spread through the bloodstream to other organs or lymph nodes outside of your abdomen. So, that’s considered to be stage IV. And then early, early stage disease is stage I. Those usually that we can just scoop them out using endoscopic procedures. They don’t even need to have full surgery. And then stage II and III is usually if there’s some involvement of the tumor through the muscle or into the muscle of the stomach and also some lymph node involvement. But that’s how we stage it.