[How does Diabetes Mellitus Influence Early Postoperative Results and Survival in Rectal Cancer?].

Introduction: Aim of this study was to investigate the influence of diabetes mellitus (DM) onto the early postoperative and long-term oncosurgical outcome after surgery for rectal cancer using data prospectively obtained in a representative number of patients.

Methods: Data (using a registration form of 68 items) from the ongoing multicenter observational study "rectal cancer (primary tumor) - elective surgery" on Quality Assurance was used including years 2008 to 2011. A voluntary and frequent follow-up was done to gain long-term data. Patients were grouped as non-diabetic and not-/insulin-dependent DM (NIDDM/IDDM).

Results: In total, 10 442 patients were enrolled; 11.0 % had NIDDM and 7.2 % IDDM. Average age of patients without DM was 67.3 [95 %-CI: 67,07; 67,55] years (yr) and was lower than in IDDM- (71.7 [95 %-CI: 71,01; 72,35] yr) and NIDDM-patients (70.9 [95 %-CI: 70.41; 71.45] yr) (p < 0.001). Tumor stages according to classification by UICC were comparable (p = 0.547). Patients with DM were more likely to be obese and to have cardiovascular and renal risk factors as well as a more critical ASA-classification (p < 0.001 each). Postoperative morbidity (in the group 65 - 74 yr; p = 0.006) and in-hospital mortality (< 65 yr; p = 0.011) was higher in patients with DM. The 5-year overall survival (OS) was 60.6 % in patients without DM. IDDM (46.4 %) and NIDDM (53.3 %) decreased the OS (p < 0.001 each). The 5-year disease-free survival (DFS) was also worsened by IDDM (p < 0.001) and NIDDM (p = 0.004). No difference was observed concerning 5-year local recurrence rate, neither for IDDM (p = 0.524) nor NIDDM (P = 0.058).

Discussion: The metabolic disorder DM has a significant impact onto the outcome after surgery for rectal cancer most likely due to its own risk potential and associated comorbidities. Postoperative morbidity and mortality were increased and the oncological survival was worsened.