Feasibility and safety of minimally invasive multivisceral resection for T4b rectal cancer:A 9-year review

BACKGROUND Colorectal cancer is the third most common cancer and the second highest cause of cancer-related mortality worldwide.About 5%-10%of patients are diagnosed with locally advanced rectal cancer(LARC)on presentation.For LARC invading into other structures(i.e.T4b),multivisceral resection(MVR)and/or pelvic ex-enteration(PE)remains the only potential curative surgical treatment.MVR and/or PE is a major and complex surgery with high post-operative morbidity.Minimally invasive surgery(MIS)has been shown to improve short-term post-operative outcomes in other gastrointestinal malignancies,but there is little evi-dence on its use in MVR,especially so for robotic MVR.This is a single-center retrospective cohort study from 1st January 2015 to 31st March 2023.Inclusion criteria were patients diagnosed with cT4b rectal cancer and underwent MVR,or stage 4 disease with resectable systemic metastases.Pa-tients who underwent curative MVR for locally recurrent rectal cancer,or me-tachronous rectal cancer were also included.Exclusion criteria were patients with systemic metastases with non-resectable disease.All patients planned for elective surgery were enrolled into the standard enhanced recovery after surgery pathway with standard peri-operative management for colorectal surgery.Complex sur-gery was defined based on technical difficulty of surgery(i.e.total PE,bladder-sparing prostatectomy,pelvic lymph node dissection or need for flap creation).Our primary outcomes were the margin status,and complication rates.Cate-gorical values were described as percentages and analysed by the chi-square test.Continuous variables were expressed as median(range)and analysed by Mann-Whitney U test.Cumulative overall survival(OS)and recurrence-free survival(RFS)were analysed using Kaplan-Meier estimates with life table analysis.Log-rank test was performed to determine statistical significance between cumulative estimates.Statistical significance was defined as P<0.05.Meier estimates with life table analysis.Log-rank test was performed to determine statistical significance between cumulative estimates.Statistical significance was defined as P<0.05.RESULTS A total of 46 patients were included in this study[open MVR(oMVR):12(26.1%),miMVR:36(73.9%)].Patients’American Society of Anesthesiologists score,body mass index and co-morbidities were comparable between oMVR and miMVR.There is an increasing trend towards robotic MVR from 2015 to 2023.MiMVR was associated with lower estimated blood loss(EBL)(median 450 vs 1200 mL,P=0.008),major morbidity(14.7%vs 50.0%,P=0.014),post-operative intra-abdominal collections(11.8%vs 50.0%,P=0.006),post-operative ileus(32.4%vs 66.7%,P=0.04)and surgical site infection(11.8%vs 50.0%,P=0.006)compared with oMVR.Length of stay was also shorter for miMVR compared with oMVR(median 10 vs 30 d,P=0.001).Oncological outcomes-R0 resection,recurrence,OS and RFS were comparable between miMVR and oMVR.There was no 30-d mortality.More patients underwent robotic compared with laparoscopic MVR for complex cases(robotic 57.1%vs laparoscopic 7.7%,P=0.004).The operating time was longer for robotic compared with laparoscopic MVR[robotic:602(400-900)min,laparoscopic:Median 455(275-675)min,P<0.001].Incidence of R0 resection was similar(laparoscopic:84.6%vs robotic:76.2%,P=0.555).Overall complication rates,major morbidity rates and 30-d readmission rates were similar between la-paroscopic and robotic MVR.Interestingly,3-year OS(robotic 83.1%vs 58.6%,P=0.008)and RFS(robotic 72.9%vs 34.3%,P=0.002)was superior for robotic compared with laparoscopic MVR.CONCLUSION MiMVR had lower post-operative complications compared to oMVR.Robotic MVR was also safe,with acceptable post-operative complication rates.Prospective studies should be conducted to compare short-term and long-term outcomes between robotic vs laparoscopic MVR.