Improved surgical technique and better knowledge of the physiological anatomy of the liver, combined with better diagnostic conditions, allowed LR to be performed more often in oncologic patients(20).
The largest indication for surgery in our sample was liver metastasis of colorectal cancer (65.1% of cases). This number is in line with the current progressive trend to operate patients with colorectal metastasis due to the advance in chemotherapy treatment, which can provide a 50% survival over 5 years(2,4). Major LR was the surgical approach used in these patients to perform a R0 resection.
The surgical outcomes of LRs are also described in other studies, such as Resende et al., which showed a rate of postoperative complications of 11.4%, including non-oncologic cases(21). Other authors such as Amico et al. show complication rates of 14.7%, highlighting intraperitoneal collection, pleural effusion and hemorrhage(20). In both national studies there was a higher rate of postoperative complications in patients undergoing major LRs.
Our study presented an overall rate of postoperative complications of 11.6%, even including a large percentage of major LRs (79.6%) - higher than the percentages found in other Brazilian series, with 31.4% and 43.2%(20,21). Considering that the complication rates have progressive increase according to the extent of LR, these values are in line with those found in literature(8).
Complication rates are also related to functional disability of the liver, and patients with Child-Pugh B or C scores have high incidence of postoperative complications, limiting in some cases the performance of major LRs(9). Since our sample included, in its majority, patients operated for colorectal metastasis and not for hepatocellular carcinoma (a condition that predisposes to liver cirrhosis and functional limitation of the liver), it is justified to perform major LRs in 69.1% of these cases.
However, patients with hepatic functional changes (preoperative elevation of AST, ALT and bilirubin) presented significantly more postoperative complications in our sample, which reinforces the need for careful prior evaluation of future liver remnant(22). Tian et al. analyzed 74 patients undergoing LR for hepatocellular carcinoma and concluded that the presence of preoperative jaundice is directly related to the patient's prognosis(23).
Lesions of larger diameters in general require more extensive resections, which can lead to further postoperative complications. The difference in the number of complications between major and minor LRs is described by Virani et al., but in our analysis there was no significant difference between the two groups (p=0.36)(24). It is worth noting that only one patient undergoing minor LR presented postoperative complications with the need for surgical reopening. The sample size did not allow a statistically significant difference in the rate of complications between major and minor LR, but with the expansion of the study it is likely that this difference is confirmed, following the pattern in the literature(24). However, we found a significant difference in survival of patients with tumors larger than 3 cm, which showed no direct correlation with the type of resection performed.
While the overall rate of reoperation described in the literature is 5.2%(24), our sample presented an overall rate of only 3.5%, demonstrating technical suitability of the service.
We understand as limitations of our study as uncontrolled retrospective characteristic. There are also limitations of technological resources due to the work being performed in a public Unified Health System teaching hospital where there are budgetary restrictions.
We can conclude that preoperative elevation of transaminases and jaundice negatively influence surgical outcomes in patients undergoing LRs. Tumors greater than 3 cm presented worse postoperative survival. Major LR did not significantly increase the surgical morbidity rate.