Bladder cancer may be suspected based on symptoms of the condition such as blood in the urine and the presence of risk factors such as a family history of bladder cancer. A diagnosis of bladder cancer usually involves the following steps:

Details of the patient’s symptoms are obtained along with the details of any risk factors for bladder cancer such as a history of smoking, exposure to certain chemicals, or a family history of the condition.

A physical examination of the rectum and vagina may be carried out to check for lumps and a urine sample arranged to test for infection or abnormal cells. If bladder cancer is suspected, a patient is referred for further tests such as cystoscopy, biopsy and a computed tomography (CT) scan.

A urine sample is tested in the laboratory for the presence of infection or abnormal cells. The process of checking urine for abnormal cells is called urine cytology. Urine cytology may not be completely accurate, sometimes detecting abnormal cells when no cancer is present or failing to detect cancer when cancer is in fact present. This test is therefore often used alongside other tests to help diagnose the condition rather than acting as a definitive test in itself.

Another useful test is cystoscopy. For this test, a long, thin flexible tube with a light and a camera attached is inserted into the urethra and used to view the inside of the bladder. The procedure usually takes 5 to 10 minutes. If cystoscopy reveals an abnormality in the bladder, a biopsy may be performed to remove tissue from the bladder for further analysis.

If a biopsy suggests that cancer cells are present, a diagnosis of bladder cancer can be confirmed with imaging studies. These tests can also determine whether the cancer has spread beyond the bladder, and if so, how far. One examples of an imaging studies is a computerised tomography (CT) scan which uses a series of X-rays to show a detailed view of the inside of the body. A contrast dye may be administered to highlight areas of abnormality. A magnetic resonance imaging (MRI) scan may also be used to detect the tumor.
 

After the cancer is detected, it is staged, which means determining how aggressive the cancer is and how likely it is to spread. This helps physicians to predict the likely outcome of treatments and choose the most appropriate therapy. The most widely used staging system for bladder cancer is the TNM system where T stands for tumor size, N for lymph node involvement and M for metastasis or spread of the cancer.

Tumor size is categorized as the following:

• TIS or CIS (carcinoma in situ) refers to very early stage cancer that is confined the innermost lining of the bladder
• Ta refers to cancer that is just within the innermost lining of the bladder
• T1 refers to cancer that has started to spread beyond the bladder lining
• T2 is the first stage of muscle-invasive cancer, where the cancer has spread beyond the connective tissue and into the muscle of the bladder
• T3 refers to cancer that has protruded the bladder muscle and spread into the surrounding fat
• T4 is advanced bladder cancer that has spread beyond the bladder to other surrounding organs

• N0 indicates no lymph node involvement
• N1 indicates involvement of a single lymph node in the pelvis
• N2 indicates that two or more lymph nodes in the pelvis are affected
• N3 indicates that one or more lymph nodes in the groin are affected.

• M0 indicates no spread of the cancer to other parts of the body
• M1 indicates that the cancer has spread beyond the bladder to other organs such as the liver, lungs and brain.