PTH-341 Initial experience with lateral pelvic lymph node dissection in rectal cancer-a pilot study

Introduction Surgery plays a pivotal role in the treatment of rectal cancer and the role of Total mesorectal excision (TME) cannot be overemphasised. This is because TME ensures removal of the locoregional nodes and has been shown to aid in reducing locoregional recurrences. However in 15% >25% of patients, the lateral pelvic lymph nodes (LPN) are known to be involved especially with rectal tumour lying below the peritoneal reflection. This is important because of the increased risk of local recurrences and poor survival associated with involvement of the lateral pelvic nodes and the fact that TME does not address removal of these nodes. Although there is no robust evidence to support Lateral pelvic lymph node dissection (LPND), LPND is being performed by selected surgeons for persistent LPLN after administration of neoadjuvant CRT. The aim of our study was to share our initial experience with LPND in patients with persistent pelvic nodes after neoadjuvant chemoradiotherapy (NACTRT) in advanced rectal cancers. Method From October 2013 to Nov 2014, 144 locally advanced rectal cancer patients (LARC) were operated with curative intent after receiving NACTRT. Of these 144 patients, 8 patients underwent TME with LPLND after NACTRT. LPND was performed when pelvic node metastasis was suspected on preoperative magnetic resonance imaging (MRI) and persisted despite preoperative NACTRT. Clinicopathological and perioperative details were recorded for these 8 patients. Results Out of the 144 patients operated with curative intent for rectal LARC, eight (5%) patients had persistent lateral pelvic nodes despite NACTRT. The median age of the patients was 42 years. An Abdominoperineal resection was the most common procedure performed. The median operative time for surgery was 240 min and the median blood loss was 800ml. Bilateral LPND was performed in three patients. The median total number of lymph nodes harvested was 8, and the total number of LPLNs was 5. Despite NACTRT 2/8 patients showed residual disease in the lateral pelvic nodes (i.e.25%). Of these two patients one also had residual disease in the mesorectal nodes. The median length of hospital stay was 6 days. Most patients were given soft diet orally on the second postoperative day. One patient had a superficial abdominal wound surgical site infection which was managed conservatively. There were no anastomotic leaks. There was no mortality within 30 days. Conclusion LPND can be performed with acceptable perioperative outcomes in carefully selected patients. Disclosure of interest None Declared.