Comparision of operative outcomes based on exposure to neoadjuvant chemotherapy in minimally invasive surgery for rectal cancer.

e15639 Background: Neoadjuvant Chemotherapy (NACT) followed by resection of tumor through surgery is the current standard of care for locally advanced rectal cancer. NACT reduces surgical complexity and downsizes the tumor, promoting an R0 resection and increasing the likelihood of sphincter preservation. These factors may contribute to differences in surgical outcomes. We aim to evaluate and compare the operative outcomes in patients exposed to neoadjuvant chemotherapy (NACT) in comparison to those unexposed to NACT, where both groups are operated via minimally invasive techniques. Methods: We conducted retrospective analysis of patients diagnosed with locally advanced rectal cancer undergoing minimally invasive surgery (Laparoscopic or Robotic) between January 2020 and January 2021. A total of 62 patients were evaluated and divided into 2 groups based on whether they had undergone neoadjuvant therapy. Primary endpoints evaluated were duration of surgery, intraoperative blood loss and number of lymph nodes dissected. Secondary endpoints considered were duration of hospital stay, CRM involvement, wound infection rates, Total Mesorectal Excision (TME) completion rates and Post operative Clavien Dindo scoring for complications. Results: Out of 62 patients included in the study, 20 patients had undergone surgery without exposure to Neoadjuvant Chemotherapy and 42 had undergone neoadjuvant treatment. ASA scores between the two groups were comparable (p<0.05). Blood Loss during surgery was found to be significantly higher in patients exposed to NACT (320.2 ± 140.1 ml) in comparison to those unexposed (255 ± 95.8 ml) (p=0.037). In contrast, duration of surgery was found to be lower in the NACT group (273 ± 80 mins) in comparison to the non NACT group (306 ± 102 mins)(p=0.225) . Hospital stay was comparable in both groups ranging between 7± 2 days and 6.5 ± 1.4 days in NACT and non NACT groups respectively (p=0.355) . Total number of lymph nodes dissected were significantly higher in the non NACT group (16 ± 6 nodes) whereas the number of nodes dissected were lower in the NACT group (9 ± 6 nodes)(p=0.002). In the NACT group, up to 16% of patients showed CRM involvement while the non NACT group showed much lower rates (5%) (p=0.41). 14% patients in the NACT group contracted wound infections while 5% patients had wound infections in the non NACT group (p=0.66). Conclusions: Patients undergoing Minimally Invasive surgery following Neoadjuvant chemotherapy had reduced dissection of lymph nodes but showed increased blood loss intraoperatively. Other outcomes evaluated showed minimal significant differences. Hence, the operative outcomes in patients undergoing MIS with and without exposure to NACT are comparable.