Bladder Cancer

Bladder cancer is the rapid, uncontrolled growth of abnormal cells in the bladder. Cancer usually begins in the lining of the bladder. The cancerous cells may spread through the lining into the muscular wall of the bladder. Invasive bladder cancer may spread to lymph nodes, other organs in the pelvis (causing problems with kidney and bowel function), or other organs in the body, such as the liver and lungs.

Bladder cancers are not all the same. Some are small and confined to the bladder lining, whereas others are large, aggressive and invade into the bladder muscle. There are also tumours that are somewhere in between these two extremes.

The majority of bladder cancers do not invade the bladder muscle and so can be treated without removing the bladder (although this may be necessary in some cases). Many of these non-muscle invasive bladder cancers require repeated treatments as the cancer has a tendency to grow back inside the bladder but are not life-threatening. As a result, your urologist will want to keep a close eye on you and see you regularly for check-ups.

There are several different types of bladder cancer and treatment will depend very much on the type, grade and stage of the cancer.
The type of bladder cancer is named after the type of cells in which they first occur, these are:

  • Transitional cell carcinoma (TCC)
  • Squamous cell carcinoma (SCC)
  • Adenocarcinoma
  • Small cell carcinoma

Grading of a bladder cancer is assessing how aggressive it is in terms of how abnormal its cells look like under a microscope. Those that are very abnormal grow more quickly. Grade can be divided into low (cells look relatively normal and are therefore less aggressive) or high (cells are abnormal or poorly differentiated and therefore more aggressive) or can be scored from 1 (less aggressive, slowly growing) to 3 (aggressive, faster growing). Often this number has a G as a prefix to show it represents the grade, e.g. G1, G2 or G3.

If the bladder cancer is confined to the bladder lining or urothelium it is staged Ta.

High grade cancer cells confined to the innermost layer of the bladder lining is staged CIS or carcinoma in situ. Unfortunately CIS is an aggressive form of bladder cancer despite it being confined to the innermost layer of the bladder.

If the bladder cancer grows into the connective tissue under the urothelium it is staged as T1.

The majority of bladder cancers fall into one of the above three categories and are termed non-muscle invasive bladder cancer.

If the bladder cancer grows into the bladder muscle it is staged T2.

If the bladder cancer grows through the bladder muscle to outside the bladder and into the fat around the bladder it is staged T3.

If the bladder cancer grows through the bladder muscle to outside the bladder and into surrounding tissues such as the pelvic wall, prostate, womb or vagina it is staged T4.

Sometimes a small letter p or c is written in front of the T, eg pTa or cT3.

  • pT means the stage has been made based on pathological or microscopic findings.
  • cT means the stage has been based on clinical (often based on imaging) findings.

If the bladder cancer has spread to lymph nodes then this is staged as N1, N2 or N3 depending on the number and position of the lymph nodes. If lymph nodes are not involved it is staged N0.

If the bladder cancer has spread to other places in the body it is staged M1. The vast majority of bladder cancers have not spread and are staged M0.

Bladder cancers fall into five broad categories based on their grade and stage:

  • Low risk non-muscle invasive bladder cancer
    These are small (less than 3cm), single low grade (G1 or G2) pTa bladder cancers.
  • Intermediate risk non-muscle invasive bladder cancer
    These are large (greater than 3cm) or multiple low grade pTa bladder cancers. Small, single low grade pT1 tumours are also in this category. Also if low risk tumours keep growing back they fall into this category.
  • High risk non-muscle invasive bladder cancer
    These are high grade (G3) pTa or pT1 bladder cancers. All large (greater than 3 cm) or multiple T1 tumours are also included. CIS is also in this category.
  • Muscle invasive bladder cancer
    These are bladder cancers which are pT2 or pT3.
  • Advanced bladder cancer
    These are bladder cancers which are pT4 or have spread to lymph nodes (N1, N2 or N3) or other sites in the body (M1).

The majority of bladder cancers fall into either the low or intermediate risk non-muscle invasive category. These cancers are rarely life-threatening but unfortunately commonly grow back requiring surveillance and repeat treatments. Treatments for patients in these two categories are aimed at keeping the bladder. Further details of treating bladder cancer can be found on this website.

Bladder cancer is commoner in men than women and gets more common as you grow older – although it can strike at any age, including childhood. In adults it is strongly related to cigarette smoking and industrial pollution.

The urine carries potential cancer causing chemicals [carcinogens] that we have inhaled or ingested – so the bladder [which stores urine for hours] is exposed for long periods of time to very small amounts of these chemicals.

Cigarette smoking is the commonest cause of bladder cancer and is known to be responsible for an estimated 40-70% of all cases of bladder cancer. Smokers' risks of bladder cancer are 2-3 times higher compared to non-smokers. It is therefore mostly a preventable condition.