Bladder Cancer: Definition and Types of Bladder Cancer
Bladder cancer is an uncommon form of cancer. It develops in the bladder tissue, the small organ that stores urine until it is ready to leave the body. Bladder cancer can develop and spread locally or it can grow and invade other organs, making it a serious disease.
An estimated 81,090 Americans will be diagnosed with bladder cancer in 2019, according to statistics from the American Cancer Society (ACS). And while most people know that smoking is linked to developing this type of cancer, there are additional risk factors that may not be as commonly known. These risk factors include: Bladder cancer can have many different subtypes based on where the tumor appears in the bladder. Understanding the different types of bladder cancer can help you understand your treatment options if you learn you have this condition.
What are the types of bladder cancer?
There are two main types of bladder cancer:
Squamous cell carcinoma – Squamous cell cancer begins in the lining of the bladder, which is known as its transitional epithelium. This is the most common type of bladder cancer, affecting about 80% of patients.
Adenocarcinoma of the bladder – Tumors in the bladder muscle, submucosal tissue, or intermuscular spaces are called bladder adenocarcinomas, affecting 20% of patients. There are also several subtypes of bladder cancer based on the type of cell where the cancer starts.
Bladder cancer begins in the lining of the bladder (transitional epithelium), submucosal tissue, or muscle. Bladder cancer is also classified by grade. Grade is a measure of how advanced the cancer is and how fast it is likely to grow and spread. The stage system (grade) for bladder cancer is the same as for other cancers, with Grade 1 being the least advanced and Grade 4 being the most advanced.
Bladder cancer also has a stage which indicates how far the cancer has spread. Staging bladder cancer is different from other cancers, because the proximity of the bladder to nearby organs makes that part of the process a little more complicated.
Squamous cell carcinoma
Squamous cell carcinoma is the most common type of bladder cancer. Squamous cells are cells that line the inside of the bladder and urethra (where urine leaves the body). Bladder cancer that starts in squamous cells is called squamous cell carcinoma. Squamous cell carcinoma takes time to grow and spread, and is treatable, but tends to recur in some patients. Squamous cell carcinoma is more common in people who smoke or have a history of bladder cancer.
Adenocarcinoma of the Bladder
Tumors in the bladder muscle, submucosal tissue, or intermuscular spaces are called bladder adenocarcinomas, affecting 20% of patients. Adenocarcinoma begins in the mucous lining of the bladder and is usually grade 1 or 2. It is more difficult to treat and is often advanced at the time of diagnosis. Adenocarcinoma is more common in people over 50 years of age and in people who have chronic bladder conditions. There is a higher chance of developing adenocarcinoma of the bladder if you have other conditions, including inflammatory bowel disease, type 1 or type 2 diabetes, or a history of bladder cancer.
Mucous adenocarcinoma begins in the mucus-producing cells in the lining of the bladder. It tends to be very aggressive, and treatment is often more extensive. Mucous adenocarcinoma is more common in people with a history of bladder cancer and in people who are immunocompromised.
Mesothelioma Mesothelioma is a rare type of cancer that begins in the thin layers of tissue that surround many of the body’s organs. Bladder cancer that starts in the cells lining the bladder urothelium (the innermost layer of the bladder wall) can become malignant and turn into mesothelioma.
Mesothelioma is often treated with a combination of surgery, radiation, and chemotherapy. It’s also common for people with bladder cancer who are at high risk for developing mesothelioma to have their bladder removed surgically. Some cases of bladder cancer originate in cells that normally line the bladder wall, but are not actually part of the bladder. These cells are called transitional cell carcinoma, and they can also form in other organs. This is a rare condition, and most cases are associated with asbestos exposure.