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