Correlation between cyclooxygenase-2 expression and body mass index on prognosis and survival of colorectal cancer of Egyptian patients

Abstract

Author(s): Fatma Gharib, Lamiss Mohamed,Dareen abd el aziz Moham

Introduction: The biologic behavior of colorectal cancer is complicated. In clinical studies, elevation ofcyclooxygenase-2 (COX-2) expression was detected in colorectal cancers when compared to the adjacent normal colonic mucosa. Moreover, obesity has been reported to cause 20% of all malignancy and contributed to almost 11% of colorectal carcinoma. Egypt Demographic Survey (2008) reported high rate of obesity among Egyptians. Both COX-2 overexpression and obesity support the different mechanisms of association between chronic inflammation and carcinogenesis. The association between clincopathological characteristics and COX-2overexpression and body mass index (BMI) together with their effect on overall survival in colorectal carcinoma (CRC) will be evaluated in this study. Methods Seventy-one non-metastatic CRC patients were prospectively included in this study. Those patients diagnosed, treated and followed up at Tanta University Hospitals. Immunohistochemistry was used to assess COX-2 expression. Body mass index was calculated at time of presentation. COX-2 expression and BMI were reported and compared with other clinicopathological criteria. Survival was assessed and compared by Kaplan-Meier curves and log-rank test Results COX-2 overexpression was detected in 49.3% of patients and significantly correlated with tumor grade(P=0.003), lymph node metastasis (P<0.001), BMI>30kg/m2(P=0.001) and gender (P<0.001). Univariate analysis revealed that COX-2 overexpression, higher grade of tumor, and high preoperative CEA status, were significantly associated with shorter overall survival. While in multivariate analysis,high COX-2 expression and tumor grade remained statistically significant with overall survival in [P =0.048; 95%CI (1.010: 12.757); HR=3.59) and P =0.034; 95%CI (1.086: 8.153); HR=2.976) respectively]. In this study, BMI>30kg/m2was reported in 53.5% of CRC cases and significantly correlated with older patients (P =0.015), femalegender(P =0.003) and lymph node involvement (P<0.001). However, no significant correlation was detected between high BMI and overall survival by univariate analysis. Conclusion Our study showed that COX-2 overexpression in addition to obesity, significantly associated with tumor characteristics and survival of CRC patients.

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