PWE-090 Are Cancers of The Colon Biologically Different Compared to Rectal Cancer?

Abstract

Introduction Emerging evidence suggests that tumour biology of rectal cancers differs from colonic cancer. This study aimed to determine which clinic-pathological factors affect lymph node yield (LNY) and survival in colonic (CC) compared to rectal cancer (RC). Methods Patients [a1] with stage I-III disease undergoing curative surgery, between 2006 and 2012, were included. Multivariate linear/logistic regression and Kaplan Meier survival analysis with SPSS version 21 were performed. Results 726 patients (M:F-398: 328, median age-70 years(63–78 yrs) were included (median follow up-58 months-(37–78 months)); 205 patients had RC. Male gender and younger age were associated with RC. A higher LNY was detected with RC compared to CC (median LNY:20 (14–27.5) versus 18 (12–25), p = 0.013). No differences in locoregional recurrence or distant metastases were found (CC 40/521 versus RC 13/205, p = 0.635 and CC 98/521 versus RC 36/205, p = 0.750 respectively). Overall survival (OS) was better in CC compared to RC (mean OS 114 months versus 90 months, p = 0.004); no difference in disease free survival (DFS) was observed. An inadequate LNY ( Conclusion An inadequate LNY is related to aspects of the primary tumour and is a marker of poor prognosis for CC patients only. No survival differences are observed for RC patients with an inadequate LNY compared to those with >12 lymph nodes questioning the prognostic significance of number of lymph nodes retrieval in RC. Disclosure of Interest None Declared