Bladder Cancer—Resection/Ablation

Abstract

Superficial bladder cancer is a misnomer commonly associated with a heterogeneous group of tumors that have not yet involved the detrusor muscle of the bladder (muscularis propria; stage T2) and includes stages Ta (no penetration of the lamina propria), Tis (carcinoma in situ [CIS]), and T1 (invasion of lamina propria into submucosa) of any grade. The treatment and prognosis of these tumors are different. Most superficial tumors present as Ta (70%), followed by T1 (20%) and CIS (10%). Superficial bladder tumor recurrence and progression are influenced by tumor grade and stage. Currently, two grading systems are commonly in use and are often used interchangeably. The standard World Health Organization (WHO) grading system includes lesions graded as 1, 2, and 3, depending on the degree of differentiation. The International Society of Urologic Pathologists (ISUP) adopted a new grading system in 1998, which also attempted to include the biologic aggressiveness of superficial tumors. This grading system includes three classes: papillary neoplasms of low malignant potential, low-grade lesions, and high-grade lesions. Although low-grade Ta lesions frequently recur (50%–70%), they progress (5%) less often than high-grade T1 lesions (80% recurrence, 50% progression) within 3 years of resection [1]. Currently, there is no uniform system for grading superficial bladder cancer. Despite the recommended WHO/ISUP classification system, most pathologists still use the traditional numeric grading system (Table 1). Tumor grade is a more important predictor of progression than stage because grade 3 tumors are 5 times more likely to progress than grade 1, compared with only twice the risk of progression for T1 stage tumors compared with lower stage Ta lesions [2]. CIS of the bladder is a high-grade, flat, noninvasive form of transitional cell cancer (TCC) which is associated