chemoradiotherapy chemoradiotherapy chemoradiotherapy (crt, crtx, ct-rt) is the combination of chemotherapy and radiotherapy to treat cancer. synonyms include radiochemotherapy (rct, rctx, rt-ct) and chemoradiation. it is a type of multimodal cancer therapy. chemoradiotherapyspecialtyoncology chemoradiation can be concurrent (together) or sequential (one after the other). the chemotherapy component can be or include a radiosensitizing agent. chemoradiotherapy as neoadjuvant therapy before surgery has been shown to be effective in esophageal cancer.