Bladder cancer classification

Pathological Classification
90% of bladder cancer are Transitional cell carcinomas (TCC) that arise from the inner lining of the bladder called theurothelium. The other 10% of tumours are squamous cell carcinoma, adenocarcinoma, sarcoma, small cell carcinomaand secondary deposits from cancers elsewhere in the body.

TCCs are often multifocal, with 30-40% of patients having a more than one tumour at diagnosis. The pattern of growth of TCCs can be papillary, sessile (flat) or carcinoma-in-situ (CIS).

The 1973 WHO grading system for TCCs (papilloma, G1, G2 or G3) is most commonly used despite being superseded by the 2004 WHO grading (papillary neoplasm of low malignant potential (PNLMP), low grade and high grade papillary carcinoma.

CIS invariably consists of cytologically high grade tumour cells.

Bladder TCC is staged according to the 1997 TNM system:


 * Ta Non-invasive papillary tumour
 * T1 Invasive but not as far as the muscular bladder layer
 * T2 Invasive into the muscular layer
 * T3 Invasive beyond the muscle into the fat outside the bladder
 * T4 Invasive into surrounding structures like the prostate, uterus or pelvic wall