Modified Response Evaluation Criteria in Solid Tumors (mRECIST)

Why Use

HCC patients undergo complex multimodal therapies, including systemic cytotoxic chemotherapy, targeted therapy like sorafenib, locoregional treatment like transarterial chemoembolization (TACE) and radioembolization with Y90), and surgical resection. Imaging criteria (versus traditional endpoints of morbidity and mortality) can more quickly identify patients who are not responding to therapy to help guide decisions about modification of therapy. Offers improved accuracy over previous criteria for tumor response (WHO and RECIST), which were developed based on data from patients receiving cytotoxic chemotherapy only. Accounts for tumor necrosis induced by treatment (which can be misinterpreted as living tumor by WHO classification).

When to Use

Patients with hepatocellular carcinoma (HCC) who have undergone treatment (systemic, locoregional, and/or surgical).

Formula

Pearls / Pitfalls

Can identify patients who are not responding to therapy, in order to help guide decisions about modification of therapy, more quickly than traditional endpoints like morbidity and mortality. Tumor response, while an important surrogate for efficacy of cancer treatment, is not equivalent to overall survival. Specific to HCC, unlike the original RECIST. Based on expert consensus and not yet validated against gold standard (pathologic examination of explanted livers), though widely used.

Management

CR, complete response. PR, partial response. SD, stable disease. PD, progressive disease. IR, incomplete response.

Advice

Contrast-enhanced CT or MRI is the imaging modality of choice for evaluating lesions. European Association for the Study of the Liver (EASL) guidelines recommend evaluating for mRECIST criteria 1 month after undergoing treatment (surgery, locoregional therapy or initiation of systemic chemotherapy).