A 52-year-old man from Delhi presents with painless haematuria for 3 weeks. Cystoscopy reveals a solitary 3 cm sessile tumour on the bladder dome. Transurethral resection of bladder tumour (TURBT) is performed. Histopathology shows high-grade urothelial carcinoma with invasion into the lamina propria but not beyond the muscularis propria. There is no involvement of perivesical fat or distant metastases on staging CT. According to the TNM classification, what is the stage of this tumour?

Explanation

## TNM Staging of Bladder Cancer **Key Point:** The T stage in bladder cancer is defined by depth of invasion: - **Ta**: Non-invasive papillary carcinoma (confined to mucosa) - **T1**: Invasion into lamina propria (submucosa) but NOT into muscularis propria - **T2**: Invasion into muscularis propria (muscle layer) - **T3**: Invasion beyond muscularis propria into perivesical fat - **T4**: Invasion into adjacent organs **Clinical Pearl:** T1 tumours are still considered non-muscle-invasive bladder cancer (NMIBC) despite lamina propria invasion. This distinction is critical for treatment decisions — NMIBC is managed with TURBT and intravesical therapy, while T2 and above (muscle-invasive) typically require radical cystoprostatectomy. **High-Yield:** In this case: - Invasion **into** lamina propria = T1 - NO invasion of muscularis propria = NOT T2 - NO perivesical fat involvement = NOT T3 - N0M0 confirmed by imaging - **Final stage: T1N0M0**