Pathology

The majority of urothelial tumours presenting in the UK are transitional cell carcinomas. Pure squamous carcinomas and adenocarcinomas represent 5% of tumours, though metaplasia can occur in a primary transitional tumour. There is a link between adenocarcinoma of the bladder and presentation of the tumour in the bladder dome, often associated with persisting urachal remnant. This type of tumour also occurs in the context of a congenital malformation exstrophy. Primary squamous cancers are the commonest subtype with bladder schistosomiasis.

Transitional carcinomas have a number of characteristic chromosomal abnormalities including, in particular, loss of chromosome 9. Other common abnormalities include a mutation of the p53 gene that appears more often in advanced cancers and has been associated with an increased risk of treatment failure.

Transitional cancers are characterized by definition of both grade and local T stage. There is a strong association between well-differentiated tumours and early stage. Most recent reports are based on the UICC TNM staging classification (1987):

♦ T1 tumours are confined to the urothelium.

♦ T2 tumours invade superficial muscle.

♦ T3 tumours extend to deep muscle and through the bladder wall.

♦ T4 tumours extend into adjacent organs.

Even when the tumour is localized the T stage is highly relevant to prognosis, with five-year survival rates of 75% for T1 tumours, 40-50% for T2 tumours, 20-30% for T3 tumours, and 10% or less for T4 tumours. Recently, this classification has been revised in UICC TNM staging (1997). Typical metastatic sites include:

♦ Pelvic and para-aortic lymph nodes

Bone metastasis is recognized increasingly as more patients have systemic control of disease with combination chemotherapy.

0 0

Post a comment