Clinical effect of local treatment based on limited segmental resection in improving the prognosis of liver oligometastasis after surgery for colorectal cancer

Objective To investigate whether local treatment based on limited segmental resection can improve the prognosis of colorectal liver oligometastases(CRLOM) compared with other non-surgical treatment method,as well as the individualized regimen of this treatment method.Methods A retrospective analysis was performed for the clinical data of 74 CRLOM patients who underwent local treatment in The First Affiliated Hospital of Kunming Medical University from January 2012 to December 2018,and according to the treatment method,they were divided into surgical group with 39 patients and non-surgical group with 35 patients.Treatment regimen and complications were compared between the two groups.The t-test or the Mann-Whitney U test was used for comparison of continuous data between groups;the chi-square test or the Fisher's exact test was used for comparison of categorical data between groups.The Kaplan-Meier method was used to plot survival curves and calculate median disease-free survival(DFS) time and overall survival(OS) time,and the log-rank test was used for survival analysis.Results Among the 39 patients in the surgical group,23 underwent laparotomy and 16 underwent laparoscopy;as for the surgical procedure,11 underwent limited segmental/subsegmental resection alone,21 underwent limited segmental/subsegmental resection combined with wedge resection of small lesions,and 7 underwent limited segmental/subsegmental resection combined with radiofrequency ablation(RFA);5 patients experienced postoperative complications,with bleeding in 1 patient,biliary fistula in 1 patient,and pleural effusion in 3 patients.Among the 35 patients in the non-surgical group,18 underwent ultrasound-or CT-guided RFA combined with transarterial chemoembolization(TACE),5 underwent TACE alone,9 underwent RFA,and 3 underwent stereotactic body radiotherapy;as for postoperative complications,1 patient experienced liver abscess after TACE,and 1 experienced pneumothorax after RFA.No patient died within 30 days after treatment.The surgical group had a DFS time of 38 months(95% confidence interval [CI]:31.3-44.9)and an OS time of 27 months(95% CI:19.9-34.0),and the non-surgical group had a DFS time of 64 months(95% CI:57.6-70.1)and an OS time of 43 months(95% CI:36.2-50.0),with significant differences between the two groups(χ2=6.072 and 11.685,P=0.014 and 0.001).The surgical group had a 1-year survival rate of 92.3% and a 5-year survival rate of 41.0%,while the non-surgical group had a 1-year survival rate of 82.8% and a 5-year survival rate of 14.3%.Conclusion Compared with non-local surgical treatment,local treatment based on limited segmental resection can significantly improve the prognosis of CRLOM in patients with colorectal cancer.The surgical procedure should be individualized according to lesion characteristics.