When Don McCoy was diagnosed with gastroesophageal junction cancer in 2025, his doctors recommended the standard treatment: chemotherapy, followed by surgery.
“They said, ‘We're going to use chemotherapy to make it smaller, then go in and cut it out,’” remembers McCoy, 74, who was diagnosed with the cancer after his family noticed he was losing weight and having trouble swallowing.
“They said, ‘You’ll be in the hospital for three weeks, and you’re going to lose all your hair,’ and they described how the stomach would be shaped like a teardrop after the surgery — it was really graphic,” he says. “And at the end of that conversation, I said ‘No, sorry, you guys. I really appreciate what we're doing so far, but I want a second opinion.’”
That’s how McCoy ended up at the University of Colorado Anschutz Cancer Center where, under the care of cancer center member Sunnie Kim, MD, he benefited from a major advance in treatment for certain types of gastric cancer: using a combination of immunotherapy drugs as the primary treatment, sparing the patient from undergoing chemotherapy or surgery at all.
“In most situations with locally advanced gastric cancer, we recommend aggressive chemotherapy with immunotherapy, and it's a pretty hefty regimen for patients,” says Kim, associate professor of medical oncology in the CU Anschutz School of Medicine. “Some of it is given before surgery, some of it is given after surgery. In Don’s case, the surgery would have been a total stomach removal, which is a life-altering surgery that would require him to change his eating habits completely.”
Kim knew of a recent small but pivotal study conducted in France in which patients with early-stage stomach cancers that expressed a feature called mismatch repair deficiency — a cellular defect that makes them highly responsive to immunotherapy — received a combination of two immunotherapy drugs and no chemo prior to surgery. When the surgery was eventually performed, around 60% of patients had no disease remaining in the primary organ at all.
“As a field, we've been talking about whether these patients even need surgery. They may be cured with immunotherapy alone,” Kim says. “By the time Don came to us for a second opinion, we had done the testing to show that his tumor harbored mismatch repair deficiency. I told him, ‘We may be able to save your stomach. We may be able to give you effective therapy that doesn't include chemotherapy.’ So he received three months of immunotherapy with ipilimumab and nivolumab, and after those three months, his scans showed little to no cancer.”
Given the treatment his previous oncologist had recommended, McCoy was amazed at the news.
“Dr. Kim is the one who detected the mismatch repair deficiency, and she said, ‘You can naturally fight this. You have an engine that can help fight this thing,’” McCoy recalls. “She said we’ll use immunotherapy, and odds are you will never lose your hair, and odds are you will never have an operation.”
McCoy started a 12-week, six-treatment course of immunotherapy infusions in August 2025, and true to Kim’s word, he didn’t lose any hair and didn’t have to undergo surgery for his cancer.
“I'm really glad to be on the cutting edge of something, and I didn’t have to get cut,” he says.
After the scans that showed little to no cancer, Kim and her team had McCoy undergo an endoscopy, which revealed a potentially troubling ulceration in the stomach. A follow-up biopsy, however, showed no remaining cancer cells.
“Then we had a discussion where we said, ‘We don't know exactly the right thing to do,’” Kim says. “‘Do we take Don to surgery regardless, or should we wait and do another endoscopy and scan in a few months and see if the cancer returns?’”
It was at that point that McCoy developed liver enzyme abnormalities, which are a known side effect of immunotherapy. His immunotherapy treatment was paused while Kim prescribed steroids to treat the liver problem.
“Then we repeated another scan, another endoscopy, and the scan looked even better,” Kim says. “We didn't see signs of the cancer, and during the endoscopy, that ulceration looked much smaller. The biopsy was negative for cancer cells, and we also implemented a test called circulating tumor DNA, where we check the blood for cancer cells, and that came back negative, too. So now he's off immunotherapy and on a surveillance plan. We're hopeful that he is going to be cured with immunotherapy alone.”
Kim says she now tests all patients diagnosed with localized stomach and esophageal cancer for mismatch repair deficiency in hopes they have an outcome like that of McCoy, who with his wife owns several retail stores in Colorado ski areas. By avoiding chemo side effects and not needing to recover from surgery, McCoy was able to devote more time to his businesses and to his hobbies, which include golfing, skiing, and racing his Corvette.
“It's so gratifying,” Kim says. “To do it without chemotherapy means the patients don't need a port. It’s a little thing, but all those little things add up to improving patients' quality of life as they go through therapy. It's been nice to be able to offer a subset of these patients with a non-chemo regimen and have it be this effective.”
For McCoy, the outcome illustrates a tenet he says he’s lived by since he was very young: always get a second opinion.
“I don't care what it is, but don't settle on the first thing,” he says. “Get a second opinion, and I recommend that to anybody. If I would have done the chemo and the surgery, I could be sitting here a shell of myself — or not be sitting here at all.”
McCoy also offers praise for Kim and her team.
“We have never met anyone there that wasn't incredibly patient and incredibly knowledgeable and just unbelievably kind,” he says. “And Dr. Kim instinctively is so fantastic. It's hard to find a mix of somebody so smart, so inventive, and so nice."
Featured image: Don McCoy with Sunnie Kim, MD