Transitional cell carcinoma

Transitional cell carcinoma is a type of cancer that arises from the transitional epithelium, a tissue lining the inner surface of these hollow organs. It typically occurs in the urothelium of the urinary system; in that case, it is also called urothelial carcinoma. It is the most common type of bladder cancer and cancer of the ureter, urethra, and urachus. Symptoms of urothelial carcinoma in the bladder include hematuria (blood in the urine). Diagnosis includes urine analysis and imaging of the urinary tract (cystoscopy).

It accounts for 95% of bladder cancer cases and bladder cancer is in the top 10 most common malignancy disease in the world and is associated with approximately 200,000 deaths per year in the United States alone. It is the second most common type of kidney cancer, but accounts for only five to 10 percent of all primary renal malignant tumors. Men and older people have a higher rate of urothelial carcinomas. Other risk factors include smoking and exposure to aromatic amines.

Treatment approaches depend on the stage and spread of the tumour. Tumour removal (resection), chemotherapy and chemoradiation may be indicated. Immunotherapy with immune check point inhibitor medications may also be suggested.

Signs and symptoms of transitional cell carcinomas depend on the location and extent of the cancer. Symptoms of bladder cancer is blood in the urine.

Urothelial carcinoma is a prototypical example of a malignancy arising from environmental carcinogenic influences. By far the most important cause is cigarette smoking, which contributes to approximately one-half of the disease burden. Chemical exposure, such as those sustained by workers in the petroleum industry, the manufacture of paints and pigments (e.g., aniline dyes), and agrochemicals are known to predispose one to urothelial cancer. The risk is lowered by increased liquid consumption, presumably as a consequence of increased urine production and thus less dwell time on the urothelial surface. Conversely, risk is increased among long-haul truck drivers and others in whom long urine dwell-times are encountered. As with most epithelial cancers, physical irritation has been associated with increased risk of malignant transformation of the urothelium. Thus, urothelial carcinomas are more common in the context of chronic urinary stone disease, chronic catheterization (as in patients with paraplegia or multiple sclerosis), and chronic infections. Some particular examples are listed below:

Transitional cell carcinomas are often multifocal, with 30–40% of patients having more than one tumor at diagnosis. The pattern of growth of transitional cell carcinomas can be papillary, sessile, or carcinoma in situ. The most common site of transitional cell carcinoma metastasis outside the pelvis is bone (35%); of these, 40 percent are in the spine.

Transitional refers to the histological subtype of the cancerous cells as seen under a microscope.

Transitional cell carcinomas are mostly papillary (70%, and 30% non-papillary).