- Statistical Analysis
Statistical analysis was performed using the SPSS ver. 22.0 (IBM Corporation, NY, USA). The prognostic value of each mast cell mediators and clinical parameters were assessed by chi-square test. The differences in the urinary mast cell mediators levels between the patients with NMIBC and healthy participants were examined using the Mann–Whitney U test. The relationship between the urinary mast cell mediator levels and the patients’ response to immunotherapy was also evaluated using the Mann–Whitney U test. The serial changes in the urinary mast cell mediators measured at four different visits were analyzed by the Wilcoxon signed rank and Friedman tests. A p-value of less than 0.05 was accepted as statistically significant.
Results
The average age at the time of immunotherapy was 56.1 (37-79) years in patients diagnosed with NMIBC. There were 13 men and 6 women. Fourteen patients were diagnosed with Ta high-grade and 5 with T1 high-grade bladder cancer. During the follow-up, while 18 patients completed two-year maintenance BCG therapy, one underwent radical cystectomy. The cystoscopic evaluations undertaken at three-month intervals revealed that 7 of 19 patients did not respond to immunotherapy (non-responders) and 12 patients responded well (responders). Among the non-responders, recurrence was observed in six patients and progression in one patient. The average time to recurrence or progression was 9.4 (3-18) months. The mean age was 52.2 ± 10.5 years in responders and 61.4 ± 10.6 years in non-responders (p = 0.098). The remaining baseline clinicopathological findings are shown in Table 1 .
The serial changes in estimated marginal means of urinary N-methylhistamine, histamine, and tryptase levels in responders and non-responders are shown in Figure 1 . There was no statistically significant difference between the immunotherapy responders and non-responders in terms of the urinary N-methylhistamine, histamine and tryptase levels (p > 0.05). However, a statistically significant increase was observed in the estimated marginal means of urinary N-methylhistamine (p = 0.027) and histamine (p = 0.004) levels measured at the second visit compared to the first visit in patients treated with BCG (Table 2 ). Although there were no statistically significant differences between the second and third visits (p = 0.053 and p = 0.26), a statistically significant decrease was detected in the estimated marginal means of N-methylhistamine levels measured at the last visit compared to the previous visit in patients treated with BCG (p = 0.013). Concerning the urinary tryptase levels, no statistically significant differences were obtained in terms of immunotherapy response and changes of urinary tryptase levels at different visits in patients treated with BCG (p > 0.05).
The estimated marginal means of urinary N-methylhistamine, histamine, and tryptase levels measured at the first visit before immunotherapy in patients with NMIBC and measured at a single visit in healthy participants are given in Table 2 . There were no statistically significant differences in the estimated marginal means of urinary histamine (p = 0.307) and tryptase (p = 0.816) levels between the patients diagnosed with NMIBC and healthy participants. However, the estimated marginal means of urinary N-methylhistamine levels were measured to be significantly higher in patients with NMIBC (p = 0.005).
The mast cell response to initial intravesical BCG immunotherapy between BCG responders and non-responders is also evaluated. The increase in the estimated marginal means of urinary N-methylhistamine was 27.24 nmol/ml in responders and 41.51 nmol/ml in non-responders (p = 340). The increase in the estimated marginal means of urinary histamine was 19.03 nmol/ml in responders and 27.64 nmol/ml in non-responders (p = 801). The increase in the estimated marginal means of urinary tryptase was 5.21 nmol/ml in responders and the increase in the estimated marginal means of urinary tryptase was 7.51 nmol/ml in non-responders (p = 108)