Pseudoprogression during treatment with pembrolizumab followed by rechallenge with chemotherapy in metastatic colorectal cancer: A case report.

Disease progression during immunotherapy in colorectal cancer does not always indicate treatment failure. A case argues that carcinoembryonic antigen (CEA) may serve as an early marker to distinguish between pseudoprogression and real progression. Presentation of results from reintroduction of chemotherapy after progression on immunotherapy that suggest increased efficiency.