Management of Disappearing Liver Metastasis Following Preoperative Chemotherapy

Preoperative chemotherapy for potentially resectable colorectal liver metastases can lead to the disappearance of up to 25% of lesions on cross-sectional imaging, a phenomenon termed “disappearing liver metastasis” (DLM). While radiologic response from preoperative therapy can be seen as a desirable outcome, DLM can be a management challenge for the hepatic surgeon. Specifically, even when a metastasis “disappears,” viable malignancy remains present in up to 80% of cases. Therefore, all initially identified macroscopic disease should be resected or ablated if a curative intent strategy is being considered. Patients with smaller lesions and those deep within the hepatic parenchyma, as well as those who receive a longer duration of preoperative therapy, are at higher risk for DLM development. Early multidisciplinary case discussion of involving the hepatic surgeon is crucial to limit this conundrum. High-quality contrast-enhanced imaging prior to initiation of chemotherapy is important in order to identify all disease. Limiting the duration of chemotherapy can be useful particularly when lesions are small and when sub-lobar resections or ablations are anticipated. In some cases with small tumors which are initially resectable, proceeding directly to surgery rather than using neoadjuvant chemotherapy should be considered. While many DLM can be identified intraoperatively with a thorough examination and intraoperative ultrasonography, an attempt to treat all original sites of disease should be made, when possible. When not achievable and occult sites are left behind, these can often be followed and managed upon recurrence with a staged approach.