Microsatellite instability (MSI) proves to be a valuable marker in predicting efficacy of immune therapy in patients with metastatic colorectal cancer. This was established in the phase 3 KEYNOTE-177 study, that was presented last year. As a result of this study, immune therapy has been cleared as first line treatment for patients with metastatic colorectal cancer that possess this MSI marker.
Colorectal cancer is the 4th most prevalent cancer in Belgium, with over 7,800 new diagnoses annually (1). Immune therapy has shown to be remarkably effective in some cases, even able to combat metastases in an advanced stage. When high levels of MSI are found in the tumour DNA, immune therapy offers better prospects for the patient.
Renowned digestive tract oncologist professor Eric Van Cutsem from UZLeuven was one of the key researchers of the KEYNOTE-177 trial. He is pleased with the clearance of immune therapy for patients with advanced colon cancer. “If analysis shows the MSI marker to be present in the tumour, I know that I can offer these patients a realistic chance of survival. Thanks to immune therapy being cleared for ‘MSI-high’ metastatic colon cancer my patients have a greater chance of progression-free survival than classical chemotherapy would offer.”
Van Cutsem continues: “The phase 3 KEYNOTE-177 study has demonstrated that immune therapy can bring a 40% reduction in the chance of progression, compared to chemotherapy. One of my patients, who had metastases in the neck, lungs and the adrenal glands, was lucky enough to be included in a clinical trial with pembrolizumab in 2015. She underwent two years of immune therapy treatment and has shown no sign of tumourous actity ever since. In the past we would call this a small miracle.”
The patient in question, a 59-year old woman named Caroline, confirms the story of professor Van Cutsem. “With a very aggressive type of colon cancer, and a body that did not cope well with chemotherapy, all treatment options seemed to be exhausted for me. Thankfully, I was included in an immune therapy trial in 2015. I am certain that that was my final option. But I managed to cope with immune therapy quite well. I did not lose my hair, I felt reasonably well and I could pretty much lead a normal life. And today, I am still here, I have even been able to return to my job. No wonder that my oncologist, professor Van Cutsem speaks of a true success story!”
2: Andre T, Shiu K, Kim TW, Van Cutsem E et al. Pembrolizumab versus chemotherapy for microsatellite instability-high/mismatch repair deficient metastatic colorectal cancer: The phase 3 KEYNOTE-177 study. Presented at: 2020 ASCO Virtual Scientific Program; May 26, 2020. Abstract LBA4.