Value of tumour-infiltrating immune cells in predicting response to intravesical BCG in patients with non-muscle-invasive bladder cancer: a systematic review and meta-analysis

Objective To investigate the predictive value of tumour-infiltrating immune cells (TIICs) on oncological outcomes and response to BCG treatment in patients with non-muscle-invasive bladder cancer (NMIBC). Materials and Methods A systematic review and meta-analysis was performed using PubMed, Scopus and the Cochrane Library in July 2020 to identify relevant studies according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The pooled recurrence-free survival (RFS) rate was calculated using a fixed-effect model. Results We retrieved 15 studies (including 791 patients) evaluating the effect of TIICs on oncological outcomes in patients with NMIBC treated with intravesical BCG. TIICs were reported to be a significant predictor of oncological outcomes and response to BCG treatment in 10 studies. Tumour-associated macrophages were associated with worse RFS (pooled hazard ratio 2.30, 95% confidence interval 1.64-3.22). Conclusions Based on these data, TIICs are significant predictors of RFS and response to BCG treatment in patients with NMIBC; therefore, incorporation of TIICs into risk stratification models may help patients and physicians in the clinical decision-making process in order to achieve the maximum possible benefit from BCG treatment.

Automated summary

The study found that tumour-infiltrating immune cells have predictive value on oncological outcomes and response to BCG treatment in patients with non-muscle-invasive bladder cancer. In particular, tumour-associated macrophages were associated with worse recurrence-free survival.