METHODS
With the permission of the local ethic committee, the patients who were diagnosed as BC in our clinic were included in the study. The demographic and clinical properties of the patients were evaluated retrospectively. Some of the patients were still smokers at the time of the diagnosis. According to our clinical policy, all patients were informed about the correlation between smoking and BC and strictly warned to quit smoking. Not only by verbal information, but a written brochure expressing the importance of cessation of smoking was given to the patients and their families. We also informed the patients for the possible progression risk of their disease with ongoing smoking. All patients confirmed that they understood the risks of smoking for their disease.
The patients underwent transurethral resection of bladder (TUR_B) and they were included to the treatment protocol according to pathologic stage and grade. In every visit, we checked if the patients gave up smoking and informed them repeatedly about the importance of cessation of smoking. In the last visit, we questioned the smoking habit of the patients. According to this data we grouped the patients as; “never smoked”, “former smokers” and “current smokers”. The former smokers group was divided into two as; former smokers that quit smoking before and after the diagnosis of BC. In order to remove the possible bias related to patient’s declaration, we also asked the same questions to the family members of the patients. The patients who had less than 6 months follow-up and the patients who had irregular visits were excluded from the study. In order to standardize the study population, the patients with pathologic diagnosis other than transitional cell carcinoma were also excluded from the study.
SPSS version 20.0 software was used for statistical analysis. The normal distribution of continuous variables was assessed by applying the Kolmogorov-Smirnov test, and the data were expressed as mean ± standard deviation or medians, as appropriate. The differences between groups were assessed using Student’s t tests for parametric data and the Mann-Whitney U test for non-parametric data. Differences in frequencies were tested using the 𝜒2 test; p values of <0. 05 were considered statistically significant. The effect of smoking habit on the recurrence and progression of BC was explored by Cox regression models. The time of follow-up was started with the time of initial transurethral resection of the BC. One-way Anova test was performed between groups that had more than 2 subgroups. The Cox regression model was formed with the variables; age, sex, stage, grade, tumor size and number of tumors which were accepted as BC prognosis factors.12