Outcome quality standards for surgery of colorectal liver metastasis

Liver metastases are the most common malignant solid liver lesions, approximately 40% of which stem from colorectal tumors. Liver resection is currently the only curative treatment for colorectal cancer liver metastases (CRLM). However, there is a lack of consensus criteria to assess the results of this treatment. In order to evaluate the quality of surgical outcomes, it is necessary to identify quality indicators (QIs) and their corresponding quality standards (QS). We propose a simple method to determine QI and QS in CRLM surgery (CRLMS) and establish acceptable quality limits (AQL) for each QI.

A systematic review of CRLMS results published from 2006 to 2016. Clinical guidelines, consensus conferences, and publications related to the CRLMS were reviewed to identify and select QIs. Once selected, a new review of the papers including the results of at least one of the QIs was performed. Statistical process control (SPC) method was applied to calculate the QS and AQL of each QI. The limits of variability were established from mean and confidence intervals at 95% and 99.8%.

The most relevant QIs and its AQLs were postoperative mortality (2%, < 4.5%), overall postoperative morbidity (33%, < 41%), liver failure (5%, < 8%), postoperative hemorrhage (1%, < 3%), biliary fistula (6%, < 10%), reoperation (3%, < 6%), R1 resection margins (18%, < 25%), and overall survival at 12 and 60 months (84%, > 77%; and 34%, > 25%, respectively).

Despite its limitations, the present study constitutes the most extensive scientific evidence to date on QI and AQL in CRLMS and may constitute a reference in future studies.