Bladder cancer at a glance
- Bladder cancer develops when abnormal cells in the bladder replicate and grow out of control.
- Bladder cancers are described as invasive or noninvasive, based on how far they have invaded into the wall of the bladder.
- The grade and stage of bladder cancer determine what treatment options are available.
- Bladder cancer occurs primarily in people over the age of 55, and men are three times more likely than woman to develop bladder cancer.
- In about half of all cases, patients are first diagnosed with bladder cancer while it is still confined to the inner layer of the bladder, making successful treatment more likely.
What is bladder cancer?
Cancer in general is the uncontrollable growth of cells that replicate and do not die as normal cells do. The causes of bladder cancer are unknown, but it has been linked to radiation, smoking and chemical exposure.
According to an estimate from the American Cancer Society, there will be about 80,470 new cases of bladder cancer diagnosed in the United States in 2019. Bladder cancer is more commonly found in men than women.
The disease is mainly diagnosed in older people, with approximately 9 out of 10 people receiving their bladder cancer diagnosis after the age of 55. The average age at the time of a bladder cancer diagnosis is 73.
To understand how bladder cancer grows, it helps to know about the four main layers of the bladder wall. The bladder wall consists of:
- Urothelium, also called transitional epithelium, is the innermost lining that is made up of urothelial cells
- Lamina propria is the thin layer of connective tissue, blood vessels and nerves covering the urothelium
- Muscularis propria is the third layer of the bladder made of thick muscle
- Fatty tissue is the fourth layer outside of the muscle that separates the bladder from nearby organs.
Most bladder cancers start in the urothelium layer of the bladder. As cancer cells grow and spread, they move into or through the other layers of the bladder. Doctors describe bladder cancers based on how far they have invaded into the wall of the bladder:
- Noninvasive cancer cells are still in the inner layer of cells (the transitional epithelium) but have not grown into the deeper layers.
- Invasive cancer cells grow into the lamina propria or even deeper into the muscle layer. Invasive cancers are more likely to spread and are harder to treat.
Doctors also define bladder cancer by the cells where cancer begins. Transitional cell carcinoma is by far the most common type of bladder cancer and occurs in the cells of the urothelium layer. Transitional cells expand and contract in the bladder as the bladder fills and empties.
Symptoms of bladder cancer
Blood in the urine is usually the first warning sign of bladder cancer. Depending on the amount of blood, the urine can change in color and appear pink, orange or sometimes even red. The frequent urge to urinate and pain or a burning sensation while urinating are also symptoms of bladder cancer. Bladder cancers that have grown large enough usually result in more serious symptoms, such as:
- Lower back pain on one side of the body
- The inability to urinate
- Loss of appetite and weight loss
- Bone pain
- Swelling in the feet.
Diagnosis & staging of bladder cancer
Bladder cancer is often diagnosed after a patient is screened for any of the symptoms described above. Following any of these indicators, a physician will run tests to confirm the diagnosis, as well as conducting a physical exam and gathering medical history.
Depending upon results, your physician may also request any of the following tests:
- Urinalysis checks for blood in the urine
- Urine cytology microscopically examines urine for cancer cells
- Tests for urine markers check for substances in urine that are indicators of bladder cancer
- Cytoscopy allows the physician to view inside the bladder using a thin tube with light and camera passed through the urethra into the bladder, which is expanded with a salt solution. If an abnormal growth is detected, the physician can take a biopsy.
- Biopsy checks tissue for cancer. The biopsy also indicates the type and the grade of cancer:
- Low-grade cancer (also called well-differentiated) has a better outlook for treatment success
- High-grade cancers (also called undifferentiated or poorly differentiated) will more likely grow into the bladder wall, making them harder to treat successfully.
Because the presence of bladder cancer is a sign that cancers may be present in other areas of the body and particularly in the urinary system, the physician may want to do imaging tests, such as CT scan, MRI, ultrasound and X-ray.
Cancers are generally classified by grades indicating the extent of the cancer and its spread. Stages of bladder cancer are as follows:
- Stage 0: Cancer has not invaded the bladder wall
- Stage I: Cancer is in the bladder’s layer of connective tissue but has not penetrated the muscle
- Stage II: Cancer has penetrated the muscle layer of the bladder
- Stage III: Cancer has grown into the outside of the bladder and perhaps to tissue and organs close by
- Stage IV: Cancer has spread to lymph nodes or parts of the body far from the bladder, or it has reached the pelvic or abdominal wall.
Treatment of bladder cancer
Based on the grade and stage, information gathered in other tests and exams, and discussion with the patient, the physician may recommend a specific treatment or combination of treatments. Generally, surgery is the best treatment option, either alone or in conjunction with other treatments defined below.