Impact of diabetes mellitus on the outcome of colon cancer

Abstract

3639 Background: Diabetes Mellitus (DM) is associated with high systemic morbidity and mortality through its effects on large and small blood vessels. Recent studies on animals and human beings have shown that DM type 2 can increase lifetime risk of colon cancer (CC) through various mechanisms like elevated levels of serum postprandial insulin and C-peptide. However the role of DM type 2 on long-term survival as well as tumor recurrence in patients with treated CC is unclear. Recent study (Jeffrey et al JCO 21(3):433–440) reported an overall increased mortality in diabetic patients with CC. To address these issues, we did a retrospective review of high-risk CC who received curative therapy. Methods: A retrospective data analysis of 564 patients with high-risk stage 2 and stage 3 CC diagnosed and treated between 01/1990 and 12/2000 was performed. Of the total 564 patients, 85 were diagnosed with DM. We then analyzed the data for rate of cancer recurrence, overall survival and disease free survival and compared between patients with DM to those without DM. Results: Of the total 564 patients, 259 (46%) were male and 305 (54%) were female. The mean age of the entire study population was 69.2 yrs (range 6 to 95 yrs), those with DM was 71.3 yrs Vs 68.9 yrs in those without DM. Stage 2 & stage 3 CC was seen in 284 (50.4%) and 280 (49.6%) patients respectively. Mean survival in patients without DM was 86 months (CI 80 - 91) and 76 months in those with DM (CI 64 to 89). Multivariate analysis with Cox regression (SPSS 10 software) did not show any survival difference (p=0.39). Rate of cancer recurrence was 13/85 (15.3%) in patients with DM as opposed to 110/479 (23%) in those without DM. After adjusting for stage, rate of recurrence was not statistically significant between the two groups (p=0.138). Stage of the CC remained a significant factor for survival (p=0.01). Conclusions: Our study showed that DM in patients with high-risk (stage 2 and stage 3) CC is not associated with increased overall mortality or rate of recurrence. Stage of the cancer remained the significant factor for both overall survival and rate of recurrence. These findings stress the need for prospective clinical research in this controversial issue. No significant financial relationships to disclose.