| BackgroundColorectal cancer(CRC)is one of the most common digestive cancers,threatening people’s lives in our country.The latest global cancer statistics report shows that the number of new cases of CRC exceeds 1930000,ranking the third(10.0%)of all malignant tumors.The number of related deaths reached 935000,also ranking the third(9.4%).Rectal cancer is an important category of CRC with a slightly lower incidence rate than colon cancer.But the data shows that the incidence rate of rectal cancer is increasing year by year.Nowadays,total mesorectal excision(TME)serves as the standard therapeutic procedure for locally advanced rectal cancer.However,the use of lateral pelvic lymph node dissection(LPLD)remains controversial.AimsThis meta-analysis was designed to assess the prognostic value of LPLD,further standard the operation principles of locally advanced rectal cancer.This study could provide newest medical evidence for clinical practice of LPLD,which would help to improve the multi-disciplinary treatment of rectal cancer.MethodsThis meta-analysis was performed in line with the recommendations from the Cochrane Collaboration.A systematic was performed for literature(from January 1965 to January 2022)in CNKI,Wan-fang database,Chinese BioMedical Literature Database(CBM),EMBASE,PubMed,and the Cochrane Library comparing radical resection plus LPLD(LPLD group)with single radical resection(TME group)for rectal cancer.Studies were considered for inclusion or excluded if they met the selected inclusion or exclusion criteria.The following data were extracted:year published,first author,country,study type,study size,clinical stage,resection status,preoperative chemoradiotherapy,height of tumor and LPLN metastasis.We used the Cochrane reviewers’ handbook to assess the quality of the randomized controlled trails(RCT).We used the Newcastle-Ottawa Scale(NOS)to evaluate the quality of cohort studies.We assessed the following outcomes:5-year overall survival,5-year disease-free survival,local recurrence,distant recurrence and grade 3-4 postoperative complications.We used Review Manager version 5.3 to perform statistical analysis.We used forest plots to present the meta-analysis results.The hazard ratio(HR)with its 95%confidence interval(CI)was used as a summary statistic for time-to-event outcomes.The odds ratio(OR)with its 95%CI was used as the summary statistic for dichotomous variables.P<0.05 was considered statistically significant.We used χ2 and I2 statistics to assess the heterogeneity of the selected studies.The funnel plot method was used to assess the possible presence of publication bias.Results1.879 publications were identified using the literature search strategy mentioned above.Among them,844 publications were excluded based on the titles and abstracts.Thus,35 studies were potentially eligible for inclusion and underwent a detailed assessment.Finally,the data of the remaining 15 studies were extracted for use in this meta-analysis,including 3 RCT and 12 retrospective cohort studies(RCS).Among them,2318 patients underwent LPLD,and 2233 underwent TME only.2.All included 3 RCTs had low risks of bias.12 RCSs were given a score of more than six,indicating high quality.3.Five studies compared 5-year overall survival between the LPLD group and the TME group.There were no significant differences in 5-year overall survival(HR=0.90,95%CI 0.77-1.05;P=0.17).Also,no significant differences were detected in subgroup analysis as well as sensitivity analysis.4.Three studies compared 5-year disease-free survival between the LPLD group and the TME group.There were no significant differences in 5-year disease-free survival(HR 1.12,95%CI 0.60-2.09;P=0.73).Also,no significant differences were detected in subgroup analysis.5.Data were extractable from 11 studies comparing local recurrence between the two groups.there were no statistically significant differences(OR 0.89,95%CI 0.53-1.51;P=0.68).Also,no significant differences were detected in subgroup analysis as well as sensitivity analysis.In this analysis,no publication bias was evident.6.Six studies,in which 1308 patients were included,reported the impact of LPLD on distant recurrence.Significant differences were not found between the two groups(OR 0.85,95%CI 0.64-1.12;P=0.24).Subgroup analysis was performed and revealed that the rate of distant metastasis did not significantly decrease.7.LPLD significantly increased grade 3-4 postoperative complications(OR 1.44,95%CI 1.03-2.02;P=0.03)compared with non-LPLD.ConclusionsBased on existing evidence,we found that LPLD did not increase 5-year overall survival or 5-year disease-free survival compared with single radical resection for locally advanced rectal cancer.Furthermore,it did not decrease the local recurrence or distant recurrence rates.However,LPLD significantly increased the rates of grade 3-4 postoperative complications.More multicenter large-scale RCTs should be conducted to further explore whether the long-term survival benefits of LPLD truly exist. |
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