Draft Key Questions
Disposition of Comments Report
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To characterize the comparative effectiveness and harms of various local hepatic therapies for metastases to the liver from unresectable colorectal cancer (CRC) in two distinct populations: patients with liver-dominant metastases (i.e., majority of disease located in the liver) who are not eligible for continued systemic chemotherapy because their disease is refractory (i.e., they have experienced disease progression while on therapy), and patients who are candidates for local liver therapies as an adjunct to systemic chemotherapy. Local hepatic therapies include ablation, embolization, and radiotherapy approaches.
We searched MEDLINE® and Embase® from January 2000 to June 2012. We also searched for gray literature in databases with regulatory information, clinical trial registries, abstracts and conference papers, grants and federally funded research, and information from manufacturers.
We sought studies reporting two outcomes--overall survival and quality of life--and various adverse events related to the different interventions for the two populations of interest. Data were dually abstracted by a team of reviewers. A third reviewer resolved conflicts when necessary. We assessed the quality of individual studies and graded the strength of the body of evidence according to prespecified methods.
We identified 937 articles through the literature search and excluded 913 at various stages of screening; 24 articles were included in our review. We also included one hand-searched article from Annals of Oncology, two published articles from scientific information packets, and three articles identified from conference abstracts; the total number of articles was 30. Twenty-three articles addressed Key Questions (KQ) 1 (effectiveness) and 2 (harms) for patients ineligible for systemic chemotherapy, and seven addressed KQ3 (effectiveness) and KQ4 (harms) for patients who are candidates for systemic chemotherapy. One randomized controlled trial (RCT) was included but this was treated as a case-series because the comparator was not relevant to this comparative effectiveness review. All others articles were case series. Fifteen studies were of good quality, 12 studies were of fair quality, and 3 were rated as poor quality. No comparative studies met our inclusion criteria. Evidence was insufficient to determine the comparative effectiveness or harms of these interventions.
In the absence of comparative data, the evidence is insufficient to permit conclusions on the comparative effectiveness of these therapies for unresectable CRC metastases to the liver. Gaps in the research base, even for critical benefits or harms, are extensive, and the quality of studies is generally questionable. Conducting RCTs (ideally head-to-head comparisons) to answer many important questions is desirable, but challenging.