ABSTRACT
Immunotherapy poses new considerations and alterations to the management of metastatic colorectal carcinoma (mCRC), where chemotherapy achieves complete radiological response but yields complete pathological response in few patients only. Immunotherapy may be superior in the conversion of unresectable disease to resectable liver lesions from mCRC and downsizing borderline lesions for more feasible resectability and achieving complete pathologic response, with the potential for cure and to alter current, established guidelines for surgical resection with a shift from chemotherapy. We present two patients with hepatic lesions from mCRC characterized by deficient mismatch repair (dMMR) which were unresectable after traditional chemotherapy but were converted to resectable lesions with a complete histopathological response following immunotherapy. Complete histopathologic response and radiologic regression or disappearance of liver lesions was observed in patients with dMMR mCRC after pembrolizumab. Immunotherapy exhibits notable potential for cure, achieving complete, successful surgical resection and improving prognosis.
