Bladder Cancer (BC): types and stages

Bladder Cancer that is in an early stage of growth may not produce any noticeable signs or symptoms. The most common sign of BC is hematuria (bloody urine; urine that appears bright red or rusty) usually is painless and may appear only from time to time over a period of months. Over 80% of all BC patients eventually do experience either gross or microscopic hematuria. BC that becomes necrotic may shed pieces of dead tissue into the urine. Fragments of papillary tissue and calcareous deposits are other forms of tumor-related matter that may be passed out with the urine.

Histology of Bladder Cancer:

Of the different types of cells that form the bladder, the cells lining the inside of the bladder wall are most likely to develop cancer. Any of three different cell types can become cancerous. The resulting cancers are named after the cell types.

Transitional Cell Carcinoma (TCC): The most common is transitional cell carcinoma which accounts for more than 93% of all BC (Lynch & Cohen, 1995). The so-called transitional cells are normal cells that form the innermost lining of the bladder wall. In TCC, these normal lining cells undergo changes that lead to the uncontrolled cell growth; characteristic of cancer.

Squamous Cell Carcinoma: These cancers originate from the thin, flat cells that typically form as a result of bladder inflammation or irritation that has taken place for many months or years. Although this is the second most common form of BC, it only accounts for 2-5% of cases in industrialized countries (Lerner et al., 2006). They are more common in developing countries where a worm infection called bilharzia or Schistosomiasis is widespread. By the time squamous cell BC is detected it is usually at an advanced stage.

Adenocarcinoma: These cancers form from cells that make up glands. Glands are specialized structures that produce and release fluids such as mucus. This is a very rare type of BC and constitutes only 1-2% of all the patients diagnosed with BC (Lynch & Cohen, 1995). Majority of adenocarcinoma are advanced at the time of diagnosis and generally does not respond to radiotherapy.

However, these three types of cancer can develop anywhere in the urinary tract.

Staging of Bladder Cancer:

The stage refers to the physical location of the tumor within the bladder or, more specifically, the tumor’s depth of penetration. In general, tumor stage is confined to one of two categories: (1) superficial, surface tumors, or (2) invasive, deep-spreading tumors. Superficial tumors affect only the bladder lining. They grow up and out from the lining tissue and extend into the bladder’s hollow cavity. Invasive tumors grow down into the deeper layers of bladder tissue, and they may involve surrounding muscle, fat, and/or nearby organs. Invasive tumors are more dangerous than superficial tumors, since they are more likely to metastasize. The staging system of BC was developed by American Joint Committee on Cancer (AJCC) (Sobin & Wittekind, 1997).

TNM System:

A TNM-Classification-System for the staging of BC was established by the UICC (Union Internationale Centre le Cancer) in 1946. “T” describes the extent of the tumor according to invasion depth in the bladder wall. “N” refers the status of regional nodal involvement, while “M” describes the presence or absence of distant metastases. The following stages are used to classify the location, size, and spread of the cancer, according to the TNM (tumor, lymph node, and metastasis) staging system.

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