An Overview of Bladder Cancer

If you or a loved one has been recently diagnosed with bladder cancer, it's important to spend some time processing the information. While you may be experiencing a range of emotions, from anger to disbelief, you should feel reassured that you're already taking the necessary first steps to coping with your new diagnosis—that is, learning about it.

In this overview of bladder cancer, we'll discuss the basics of what the bladder is and its role in the urinary tract system, how cancer develops there, and common terms used to describe different types of the condition. Make sure you are fully equipped to have an informed discussion with your healthcare team.

The Urinary Tract System

The urinary system consists of the following organs:

The kidneys are two bean-shaped organs located in the back of the abdomen, beneath the diaphragm on the left side, and beneath the liver on the right side. They have three main functions:

  1. Filter waste from the blood
  2. Make urine
  3. Regulate both blood pressure and salt and water balance

When urine is produced by the kidneys, it travels through a tube connected to each kidney, called a ureter. The ureters are lined with muscles and nerves that act to drive the urine down into the bladder.

The bladder is a hollow, muscular organ that stores urine—around two cups at a time—and is located in the pelvis. When you urinate, contraction of the bladder, which is controlled by your brain and spinal cord, releases urine out of the bladder into the urethra, a duct that carries urine outside of the body.

In men and women, the urethra serves the same function. Although, in men, the urethra does pass through the prostate gland, a walnut-sized organ that is located near the bottom of the bladder. While the prostate gland is involved in fertility in men, it does not contribute much to a man's urine flow.

How Bladder Cancer Develops

Organs are made up of cells and, in a healthy organ, the cells grow and divide in a controlled, orderly fashion. But, sometimes, when the cells within an organ begin growing and dividing in an uncontrolled manner, cancer may occur.

These cancer cells keep multiplying, eventually forming a tumor or mass that can invade nearby healthy tissues, affecting their function and potentially causing symptoms (like blood in the urine or pain). If not treated, cancer can enter the bloodstream and/or nearby lymph nodes and spread to other parts of the body.

The bladder consists of multiple layers and each layer is made up of different cells that serve a different function. The innermost layer of the bladder, called the urothelium, is where most bladder cancers begin.

The cells in the innermost layer are called transitional cells, which is why you may have heard the term transitional cell carcinoma or urothelial carcinoma. (Carcinoma is another word for cancer). The transitional cells stretch when the bladder is full of urine and shrink when the bladder is empty.

Just outside the urothelium is a thin layer of blood vessels and nerves followed by a thick muscular layer and then a layer of fat. As bladder cancer grows, it can expand into or through these layers.

Once bladder cancer has expanded into the thick muscular layer, it is considered to be invasive, which means it is more difficult to treat. Superficial or non-invasive bladder cancer is easier to treat, as it is contained.

The big picture here is that the more bladder cancer expands out, the more advanced it becomes and the more challenging it can be to treat. Eventually, bladder cancer can spread to areas outside the bladder or even to other organs, like the bones, liver, or lungs. This process is called metastasis.

Types of Bladder Cancer

Whether you or a loved one has been diagnosed with bladder cancer (or you simply want to learn more about it), it is important to remain proactive in your bladder and overall health. Learn what you can, but try not to get too bogged down in the details.

Stick with the big picture, file some of these terms away, and be sure to address any questions or worries with your doctor. Here are some of the different types of bladder cancer and what your need to know.

Urothelial Cancer

Urothelial carcinoma (also known as transitional cell cancer) is the most common type of bladder cancer, occurring in 90 to 95 percent of patients. It has two subtypes:

  1. Papillary carcinoma
  2. Flat carcinoma

These subtypes describe how cancer appears and grows within the bladder. A papillary carcinoma looks like a finger and grows from the innermost layer of the bladder, the urothelium, towards the center. And, because they grow toward the center, they tend to avoid invading the outer layers of the bladder.

In contrast, a flat carcinoma looks like a flat mass or growth lying on the innermost surface of the bladder. Unlike papillary carcinomas, they do not grow towards the center.

Cigarette smoking is the biggest risk factor for developing urothelial carcinoma. It accounts for half of all cases of the disease in the United States.

Squamous Cell Cancer

Besides urothelial carcinoma, there are other types of non-urothelial bladder cancers, but these are not very common. For example, squamous cell carcinoma of the bladder begins in skinny, flat cells called squamous cells that may form in the bladder after long-term infection.

A classic example of squamous cell carcinoma of the bladder is in a person infected with the parasite Schistosoma haematobium, found in Africa and the Middle East. Chronic urinary tract infections or irritation from an indwelling catheter may also be risk factors for developing it.

Adenocarcinoma 

This type is rare, accounting for approximately one to two percent of all bladder cancers in the United States. Like squamous cell carcinoma, infection with the parasite Schistosoma haematobium or chronic irritation of the bladder can increase a person's chance of developing adenocarcinoma.

Other Types

There are other less common types of bladder cancer, like small cell carcinoma of the bladder and melanoma. Regardless of the type, however, treatment is generally similar for early-stage bladder cancer, although chemotherapy may vary.

Bladder Cancer: Stages and Grades

Determining how far a person's bladder cancer has spread is called staging. This is a very important aspect of a doctor's evaluation as it dictates a person's treatment plan.

The grade of bladder cancer is also an important part of a doctor's evaluation and refers to how the cancer cells look under a microscope. Bladder cancer can be either low-grade, meaning the cancer cells look more like healthy bladder cells, or high-grade, meaning the cancer cells appear abnormal and not like healthy bladder cells.

Low-grade bladder cancer rarely spreads into the muscle layer of the bladder, whereas high-grade cancer is more likely to. Overall, this means that low-grade bladder cancer generally offers patients a better chance of recovery.

A Word From Verywell

Navigating bladder cancer requires time and patience and an expectation that the road ahead may be bumpy at times. But with the right care team and attitude, you or your loved one can best handle what's to come. Remain proactive by asking questions and be sure to continue to make healthy choices daily.

View Article Sources
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