Prognostic role of the tumor-associated tissue inflammatory reaction in transitional bladder cell carcinoma

Many authors have indicated that the presence of an inflammatory response within the tumor may predict not only recurrence and progression but also survival in several tumors, including transitional cell carcinoma (TCC) of the urinary bladder. Several studies have been performed with a mean follow-up period that is often too limited for predicting patient outcome. The aim of the present study was to define the influence of inflammatory cell infiltrate on recurrence, progression and survival in TCC of the bladder over a long follow-up period. Between January and December 1995, 410 consecutive patients, who had undergone transurethral or open surgery for bladder tumors at the same urologic center, were selected for the study. All cases were reviewed to assess histotype, stage and grade of the tumor and presence or absence of tumor-associated inflammatory reaction. To better evaluate the prognostic role of each single factor in TCC, a follow-up of 10 years after surgery was performed. Pathologic evaluation showed superficial TCC in 312 patients, while 98 had an invasive bladder tumor. Three among 410 bladder tumors were squamous cell carcinomas. Out of 407 TCCs, 119 (29.23%) presented inflammation within the tumor or the lamina propria. At 10 years follow-up, a statistically significant association was shown between the presence of inflammation within the tumor or lamina propria and the number of recurrences (p<0.0001). Moreover, the absence of inflammatory infiltrate in the tumor established the relative risk of suffering more than one recurrence at 2.287 (95% CI 1.180-3.346). The Mann-Whitney test confirmed a statistically significant difference between superficial bladder tumors with inflammation and those without (26.3 vs 11.5 months, p<0.001). In terms of survival rate, a statistically significant difference was reported between carcinomas with and without inflammation (p=0.0261). On multivariate analysis, the presence of inflammation within the tumor was found to be an independent predictor of survival in patients with TCC of the bladder (p=0.027). Survival analysis by means of the Kaplan-Meier curves showed a statistically significant difference between patients with tumor-associated inflammatory reaction and those without (p=0.0098). These results confirm that the presence of inflammatory reaction has a good prognostic value in transitional bladder cell carcinoma. However, to better define its prognostic significance, the characterization of inflammatory cells in tumor-associated tissue reaction must be accomplished.