ABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship between renal clear cell carcinoma and type 2 diabetes mellitus (DM).</p><p><b>METHODS</b>Two hundreds and sixty-four patients with renal clear cell carcinoma and four hundred controls who suffered from non-urinary system, non-neoplastic or non-hormone-related disorders, were enrolled from January 2008 to December 2012. The incidence of diabetes between the 2 groups and the relationship between renal clear cell carcinoma and duration of diabetes were compared, moreover, renal clear cell carcinoma patients with DM were compared with patients without DM for their clinical features, laboratory examinations and histological characteristics.</p><p><b>RESULTS</b>The comparison of renal clear cell carcinoma group and control group: the incidence of DM in the two groups were 19.7% and 12.8% respectively, and the difference was significant (χ(2) = 5.86, P < 0.05, OR = 1.68). In the renal clear cell carcinoma group, the proportion of patients with DM diagnosed within 2-4 years was 4.92%, which were significant higher than those in the control group 1.70% (χ(2) = 5.49, P < 0.05, OR = 2.91). And men with diabetes had high occurrence risk 86% of renal clear cell carcinoma (OR = 1.86, 95%CI: 1.09-3.15). The comparison of diabetes patients subgroup and non-diabetic patients subgroup in renal clear cell carcinoma group: in respect of clinical features, greatest tumor diameter in the two subgroups were (4.9 ± 2.3) cm and (4.2 ± 2.1) cm respectively, and the difference was significant (t = 1.96, P < 0.05). However, there was no significant difference in terms of age, gender and cancer location between the two subgroups (P > 0.05). In respect of laboratory examinations, serum creatinine in the two subgroups were (72 ± 20) µmol/L and (65 ± 17) µmol/L, and the difference was significant (t = 2.34, P < 0.05); serum urea nitrogen in the 2 subgroups were (7.1 ± 2.1) mmol/L and (6.0 ± 1.5) mmol/L respectively, and the difference was significant too (t = 1.47, P < 0.05). In respect of histological characteristics, the proportion of well differentiated clear cell carcinoma were 80.8% and 81.1% respectively, and the difference was significant (χ(2) = 4.23, P < 0.05). The proportion of stage II were 25.0% and 27.8% respectively and the difference was significant (χ(2) = 4.08, P < 0.05).</p><p><b>CONCLUSIONS</b>DM is closely related with renal clear cell carcinoma and DM may be a possible risk factor for the tumor. And for elderly patients with diabetes who appear waist discomfort or hematuria, a careful examination of kidney is important to make early diagnosis, give timely treatment and improve survival prognosis.</p>