EP164 - Diverting Loop Ileostomy Omission in Robotic TME after neoadjuvant radiation therapy — is it safe ?

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Purpose/Background: The creation of a diverting loop Ileostomy after a Total Mesorectal Excision (TME) for middle and low rectal cancers, was initially established to mitigate the risk of anastomotic leaks, and the complications associated to it, that could severely impact in mortality and morbidity rates. Current available evidence shows that in the abscence of such safeguard, the risk of severe infections, sepsis and the need for urgent reoperations are all greatly increased; meaning greater morbidity, hospitalization rates, expanses and, potentially, death. However, the true need for a diverting loop ileostomy in robotic TME is yet to be determined.

Methods/Interventions: We analyzed the American College of Surgeons National Surgical Quality Improvement database for the targeted procedure of proctectomy in the calendar year 2022. We included cases of low and middle rectal cancer treated with robotic approach after neoadjuvant radiation therapy. We further divided cases as diverting loop ileostomy if CPT codes 44145, 44146, 44187, 44208, 44310 were include as concomitant procedures. We also analyzed, within the robotic TME cohort, whether neoadjuvant radiation therapy was associated with the incidence of anastomotic leak. We conducted Poisson Regression and linear regression models adjusting for age, preoperative albumin level, weight, sex, ASA score, smoker status, diabetes, pT and pN status, hypertension and NSQIPs built-in estimated morbidity probability scoreto analyze anastomotic leak and unplanned reoperation. Secondary outcomes included ileus and adverse events including either renal failure, blood transfusion, respiratory and cardiac complications, postoperative sepsis, deep and superficial surgical site infection.

Results/Outcomes: We included 462 cases of low and middle rectal cancer with robotic approach after neoadjuvant radiation therapy for analysis. Of those, 414 (89.61%) received a diverting loop ileostomy. For the subset of patients who did not receive a diverting loop ileostomy, there was no significant difference in the incidence of anastomotic leak, regardless of neoadjuvancy status (1.82 % vs 2.09 %).
There was no significant difference in the incidence of anastomotic leak across groups who received neoadjuvant radiation therapy (1.93 % in the ileostomy group and 4.17% in the non-ileostomy group) after multivariate analysis (adjusted RR 1.70, 95 % CI {0.79 - 3.76}, p=0.092). Similarly, there was no significant reduction in the unplanned reoperation rate (adjusted RR 1.85, 95 % CI {0.45 - 7.55}, p = 0.387. No significant difference was observed in postoperative morbidity (adjusted RR 1.56, 95 % CI {0.48 - 5.07}, p = 0.454). We did not observe a significant increase in postoperative ileus when a diverted loop ileostomy was performed (adjusted RR 0.78, 95 % CI {0.28 - 2.20}, p=0.649

Conclusion/Discussion: In this cohort study, omission of diverting loop ileostomy in robotic mesorectal excision of low or mid rectal cancers after neoadjuvant therapy was not associated with increased incidence of anastomotic leak, unplanned reoperation, postoperative morbidity, or postoperative ileus. Also, neoadjuvant radiation therapy was not associated with increased incidence of anastomotic leak Further studies are needed to determine the absolute indications for diverting ileostomy in the setting of neoadjuvant radiation.