Fancier and More Expensive Doesn’t Mean Better: An Argument for CT Staging of Patients with Colorectal Liver Metastases

Excerpt

We are deeply concerned with the concluding algorithm proposed by the authors in the recently released review article, which recommends a significant shift in preoperative imaging for patients with colorectal liver metastases from CT to MRI plus PET.1 Independent of the potential negative impact on patients, providers, and healthcare economics, we disagree with the interpretation of the literature used to support their algorithm in three areas. First, with regard to the sensitivity of CT versus MR, we believe that one of the primary meta-analyses used to support the authors’ algorithm is flawed.2 A majority of the studies included in this meta-analysis do not include data on CT scanning parameters and/or they document suboptimal CT techniques, such as wide slice intervals, lack of triphasic CT protocols, and inadequate contrast bolus rate/volume. Indeed, every included study that documented adequate CT technique for the detection of small lesions found equivalence to MR. Second, Table 1 contains no information on specificity. Our experience with both CT and MR techniques indicates that the vast majority of additional small indeterminate lesions identified with MR are benign and do not impact the treatment strategy. Our experience is that both modalities are equivalent for lesion characterization, particularly when the effect of neoadjuvant chemotherapy is taken into account, because CT is far more effective as a measure of treatment response.3 Third, in practice, the accuracy of PET is far less than optimal. For patients who recently received chemotherapy, the sensitivity of PET drops by half.4 Also, false-positive PET findings are frequent, potentially distracting treating physicians from curative therapies. …