The effect of variant histology on oncological results in non-invasive bladder cancer cases

Objective: In this study, it was planned to investigate the effect of variant histology on oncological results in superficial non-muscle invasive (Ta / T1) bladder cancers. Material-Methods: The records of patients who underwent transurethral resection-bladder (TUR-M) surgery for primary non-muscle invasive bladder cancer between 2010 and 2020 in the Urology Clinic of Çukurova University Faculty of Medicine were retrospectively analyzed. 356 patients diagnosed with pure non-muscle invasive urethelial carcinoma and 28 patients diagnosed with variant histology were included in the study. Histological grading of cancers was made according to the 2004 WHO classification. TNM 2009 classification of UICC was used for staging. After TUR-M, the patients were divided into two groups according to their histopathological grading as superficial (Ta / T1) pure urethral carcinoma and superficial (Ta / T1) variant histology urethral carcinoma. The treatments received by the patients, recurrence, metastasis and death information during the follow-up period were recorded and anlyzed. IBM SPSS Statistics Version 20.0 package program was used for statistical analysis of the data. Categorical measurements were summarized as numbers and percentages, and numerical measurements as mean and standard deviation (median and minimum - maximum where necessary). Chi-square test was used to compare categorical measurements between groups. T test was used in independent groups for comparing numerical measurements between groups. Log-Rank test was performed under Kaplan-Meier analysis to examine the relationship between survival time (the time between diagnosis and last follow-up) and variables. Statistical significance level was taken as 0.05 in all tests. Results: In our study, patients diagnosed with non-muscle invasive pure urethelial carcinoma (SUC) and patients with variant histology diagnosis of urethral carcinoma (VUC) were compared. When the mean overall survival was compared, the average overall survival of VUC was worse than the SUC (p = 0.046). There was no significant difference in overall survival between patients with a diagnosis of SUC and VUC who received BCG therapy (p = 0.547). There was no statistically significant difference in overall survival between patients with a diagnosis of SUC and VUC who underwent radical cystectomy (RC) (p = 0.481). A statistically significant difference was found in overall survival between patients with SUC and VUC who received chemotherapy (p = 0.027). When patients with recurrence in the bladder were compared, mean survival time of those with recurrence was found to be shorter than those without recurrence, but this was not statistically significant(p = 0.710). When we divided the patients with diagnosed VUC according to variant histology types, since the number of some variant histology types was low, the patients were divided into squamous, micropapillary and others (glandular, nested, mucinous, sarcomatoid types) and overall survival analysis was performed. The mean survival time was found to be shorter in patients diagnosed with micropapillary variant histology. However, it was not statistically significant. It was thought that this result was affected by the low number of patients. Conclusions: VUC was found to be significantly worse in terms of overall survival when all patients with non-muscle invasive SUC and VUC diagnosed and patients who received chemotherapy were compared with overall survival. There was no difference in overall survival between patients with BCG and RC treated SUC and VUC. Since there is no significant difference in survival between patients with a diagnosis of SUC and VUC who receive BCG treatment, intravesical BCG treatment is also effective in patients with a diagnosis of superficial VUC. However, since the number of patients with variant histology included in the study is low, comparison between variant histology subtypes compared to BCG treatment is not possible, further research is needed to determine which subtype BCG treatment will be more effective. Since variant histology does not make any difference in survival in patients undergoing radical cystectomy, early RC can be safely applied in bladder cancers with superficial variant histology. Chemotherapy is more effective in patients with SUC diagnosis. Overall survival is poorly affected in VUC patients receiving chemotherapy. When patients diagnosed with VUC were compared with variant subtypes, it was observed that the micropapillary variant had a worse prognosis. However, due to the low number of patients and variant histology subtypes included in our study, further research is needed among subtypes. Keywords: Bladder cancer, pure urothelial carcinoma, variant histology urothelial carcinoma, BCG