Preoperative staging of locally advanced bladder cancer before radical cystectomy using 3 tesla magnetic resonance imaging with a standardized protocol

摘要

Objective. The correlation between clinical tumour stage and pathological tumour stage in radical cystectomy specimens in locally advanced bladder cancer is suboptimal. Radiological methods have so far been of limited value in preoperative staging; however, the resolution with magnetic resonance imaging (MRI) has improved with further technical developments of the method. The aim of this study was to compare tumour stage at MRI with pathological tumour stage in the cystectomy specimen. Material and methods. Prospectively, 53 patients with invasive bladder cancer were preoperatively investigated with 3 tesla (3T) MRI using a standardized protocol. 3T MRI was performed at a standardized bladder volume. Clinical tumour stage, tumour stage at MRI and pathological tumour stage groups (Ta, Cis, T1/T2a, T2b/T3a, T3b/T4a), were compared, and sensitivity and specificity for organ-confined and non-organ-confined disease (stage T3a or above or lymph-node metastases) were analysed. Results. MRI overestimated tumour stage in 23 out of 47 patients (49%), whereas six patients (13%) were understaged. In the three groups of patients (those with the same stage group at MRI as in the cystectomy specimen, overestimated tumour stage and understaged patients), the time interval between transurethral resection of the bladder (TURB) and MRI did not differ significantly. Conclusions. Preoperative MRI overestimated tumour stage in almost half of the patients investigated in this study. Postoperative changes could have contributed to such overstaging with MRI.