Thick tongue coating: diagnostic markers for metastatic colorectal cancer?

摘要

Background: According to World Health Organization, colorectal cancer is the third most common cancer in the world. The prognosis assessment and condition judgment of the colorectal cancer remains a challenge clinically. Therefore, identification of diagnostic markers to evaluate the prognosis of colorectal cancer clinically should be urgently developed. We have observed that a lot of cancer patients had thick tongue clinically, but what is the relationship between tongue coating and the tumor? Methods: Seventy-four patients with colorectal carcinoma were collected through the outpatients of Tianjin Medical University Cancer Institute and Hospital from May 2010 to September 2011, in which there were 49 patients confirmed with recurrence or metastasis. All photos of patients’ tongue were taken with a SONY camera in the same room and under constant conditions such as brightness or distance. Regression equation predicting thickness of tongue coating was constructed using binary logistic regression analysis. The optimal cut off of probabilities to diagnosis thick tongue coating was determined by receiver operating curve analysis. χ2 test for paired data and kappa test were used to determine the diagnostic value for recurrence and/or metastasis in colorectal cancer patients. Kolmogorov-Smirnov test was used to determine the distribution of ALT, AST, ALP ALB, TP, GLO, TBIL, DBIL, GGT, LDH, GLU, UA, CA724，CA199，CA242 and CEA. Data with the skewed distribution were presented as median (quartile interval). The association between the thickness of tongue coating and clinical-pathological character was evaluated by chi square test and two-independent-sample test. The two-independent-samples χ2 was used to determine whether there were significant differences in the thin coating and thick coating between patients with recurrence and/or metastasis and patients without recurrence and/or metastasis. Kaplan-Meier method was used to analyze survival time. Statistical analysis was performed by SPSS (version 16.0). Results: Through retrospective clinical study we found that overall survival of colorectal cancer patients with thick greasy tongue coating is less than the patients with less tongue coating. What’s more, the risk for recurrence or/and metastasis overall survival in thick coating group was higher than thin coating group. In addition, the histological staining of the tongue slices of rats showed that EGFR receptors in the tongue root were the most among whole tongue surface. Tongue thick coating may be due to tumor patients with high levels of serum EGF which results in significantly increasing tongue coating. This finding suggested that the tongue coating of cancer patients may reflect the level of serum EGF levels in patients which may be related to shorter survival time. In addition, another study showed that serum lactic dehydrogenase level in patients with thick tongue coating is higher than patients with thin tongue coating. Conclusions: These studies suggest that tongue coating is likely to reflect some of the growth factor and enzyme levels. By observing the tongue coating we could predict the prognosis of patients and the characteristics of tongue coating may be used as new diagnostic markers to patients with colorectal carcinoma.