Long-Term 5-Year Response to Pembrolizumab, Bevacizumab, and Capecitabine Regimen in a Metastatic Colon Cancer Patient with MSI-High and KRAS Mutation: Case Report.

With an estimated 1.88 million new cases and 0.92 million deaths in 2020, colorectal cancer accounts for nearly one-tenth of all new cancer and cancer-related deaths worldwide. Nearly half of the patients of colorectal cancer are diagnosed with metastatic or inoperable disease with a very dismal 5-year survival rate. Chemotherapy, targeted therapy, and immunotherapy have been used to treat metastatic disease, either alone or in combination. We present a case of recurrent metastatic colon carcinoma with KRAS exon 2 mutation and high microsatellite instability that was treated with a combination regimen of bevacizumab, capecitabine oral chemotherapy, and pembrolizumab immunotherapy. At nearly 5 years of treatment, the patient is alive with good performance status and improved quality of life owing to a favorable response to the molecular profiling-based treatment approach.