Complete radiological response of colorectal liver metastases (LM) after chemotherapy: Does it mean cure?

Abstract

3501 Background: Most of patients with colorectal LM receive systemic chemotherapy. Complete response on imaging is considered a good indicator of the efficacy of chemotherapy. Whether complete radiological response is correlated to complete pathological response is not well known. The objective of this study was to determine the significance of complete radiological response of LM after chemotherapy. Methods: Between 1998 and 2004, 586 patients were treated in one institution for colorectal LM. 38 with the following criteria were included in the study: less than 10 LM before chemotherapy, disappearance of one or several LM on helical CT scan and ultrasound after chemotherapy, surgery with liver examination and intraoperative ultrasound within 4 weeks after imaging, no extra-hepatic disease, follow-up at least one year after surgery. Results: Overall, 66 LM disappeared on imaging after chemotherapy (38 patients). In 9 patients, persistent macroscopic disease was observed at surgery at the site of 20/66 (30%) LM although there were considered in complete response on imaging. In 15 patients, with no remnant disease at surgery, the sites of 15 initial LM were resected. Pathological examination of theses sites of LM considered in complete response showed the presence of viable tumor cells in 12/15 cases (80%). In 14 other patients, the sites of 31 initial LM, which were not visible at surgical exploration were left in place during surgery. After one year of follow-up, 23/31 (74%) LM considered in complete response had recurred in situ (11/14 patients). Overall, persistent macroscopic or microscopic residual disease or early recurrence in situ were observed in 55/66 LM (83%) with complete radiological response (32/38 patients). Conclusions: Complete radiological response in patients who have received chemotherapy is a useful tool to evaluate the effect of chemotherapy but it does not mean cure in most patients. This should be taken into account when considering multimodality treatment including chemotherapy and surgery. No significant financial relationships to disclose.