Abbreviations: CONSORT: consolidated standards of reporting Trials; Hb: haemoglobin; NMIBC: non-muscle-invasive bladder cancer; TUR: transurethral resection; (B-)(M-)TURBT: (bipolar) (monopolar) transurethral resection of bladder tumour. This evidence concerns the gene GSTM1 and urinary bladder neoplasm.