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Letter from the Editor

We read the recent article “Correlation of size and clinicopathologic characteristics based on updated definitions” published by Taskin and colleagues with great interest [1]. The authors have designed a study to correlate the size and the pathologic characteristics of gallbladder polyps. The aim of this letter was to make a detailed analysis of the mentioned study with the guidance of the current literature and our clinical experience about relationship between gallbladder polyp size and risk gallbladder cancer. Gallbladder polyps are defined as lesions protruding from the gallbladder wall to the lumen [2]. Generally, these lesions are benign in nature; however, the main challenge is to differentiate the lesions with malignant potential. Therefore, early detection of these lesions provides early treatment and prevention of development of the gallbladder cancer [3]. The prevalence of polypoid lesions of the gallbladder ranges between 4.3 and 6.9% and it is even more common in cholecystectomy specimens which may be seen up to 12% of the specimens [4,5]. The median age at diagnosis is reported to be nearly 50 years of age and although, it has been reported to be 1.5 times more common in male than the incidence in the female, there are studies suggesting and equal distribution among gender [6–8]. The polypoid lesions of the gallbladder are divided in to benign and malignant subdivisions. The malignant polypoid lesions are gallbladder cancer. The benign polypoid lesions can be pseudotumor including cholesterol polyps, inflammatory polyps, cholesterolosis, and hyperplasia. Other benign polypoid lesions are epithelial tumors including adenoma; and mesenchymal tumors such as fibroma, lipoma and hemangioma can also form polypoid lesions in the gallbladder [3]. The risk factors for developing gallbladder polypoid lesions include old age, male gender, lipid metabolism disorders, obesity, diabetes mellitus, fatty liver, and polypoid lesions such as Peutz Jeghers and Gardner syndromes. There seems to be an inverse relationship between the occurrence of gallbladder polyps and cholelithiasis [9,10]. Because, the presence of cholelithiasis may obscure the diagnosis of polypoid lesions of the gallbladder. The risk factors associated with developing cancer in gallbladder polyps include polyp size, growth of the polyps over time, old age, diabetes mellitus, sessile polyp, sclerosing cholangitis, ethnicity, single polyp, concomitant cholelithiasis, and gastrointestinal polyposis syndrome [11–14]. There is no specific tumor marker to differentiate between malignant and benign lesions. This may be due to the fact that malignant polypoid lesions are earlystage gallbladder cancer and the lesion too small to produce detectable tumor markers [5]. Recently, a large cohort including 622.227 patients, the gallbladder cancer incidence was 11.3 per 100.000 population. The risk increased 98 times when the polyps smaller than 6 mm was compared to polyps ranging between 6 and 10 mm. Increase in polyp diameter during follow-up was not associated with increased risk of gallbladder cancer development [15]. The most important point related with the study is that there is discrepancy in the number of patients reported in different parts of the article. In the abstract section, the authors have stated that they have analyzed a total of 4231 patients with gallbladder polyps and 606 of which were gallbladder cancer. However, in Fig. 3, the total number of patients (3715 + 606) with gallbladder polyps adds up to 4321. This unintentional mistake should be corrected because a difference of 90 patients could affect the outcome of the statistical analysis. We would also like to emphasize the statistical analysis method and style of expression of the variables. The authors have stated that they have used Shapiro-Wilks test for evaluation of normal distribution of the continuous variables. Furthermore, the authors state that they have used Mann-Whitney U test for evaluation of the two independent samples and Kruskal-Wallis test for evaluation of multiple group variables. This means that the data did not distribute normally and therefore, the authors used the non-parametric tests to evaluate the data. In addition, the mean and the SD values in the present study is very close to each other and therefore, we can certainly say that the data does not show a normal distribution. We would like to make a critical suggestion at this point. Shapiro-Wilks test is not a suitable test for evaluation of normal distribution if the sample size is more than 50. The test that should have been chosen would be the Kolmogorov-Smirnov test [16]. Since the data did not show a normal distribution, the continuous variables should be expressed as median (minimum-maximum) or median (interquartile range (IQR)) [17–19]. In Table 1 of the mentioned study, the age of the patients was expressed as mean (min-max) and diameter of the polyps were expressed as mean ± standard deviation (SD) and median (IQR). A main point that we would like to emphasize about the present study is related to the absence of correlation analysis. The authors have stated in the heading of the study and also multiple parts of the article that the objective of the study was to correlate the size of the gallbladder polyps and clinicopathologic characteristics of the patients. However, they have not performed any correlation analysis. Scientifically, correlation analysis is vital. We have performed the correlation analysis according to the data presented by the authors. We present our data in a table (Table 1) through this commentary.