Urothelial Carcinoma (Transitional Carcinoma)

Urothelial carcinoma — also called transitional cell carcinoma — is cancer that starts in your urothelium. This is the tissue that lines parts of your urinary system. Urothelial cells line your bladder. They also line a part of your kidney called the renal pelvis, as well as your ureters. Ureters are tubes that carry pee from your kidney to your bladder.

Urothelial carcinoma accounts for about 90% of all cases of bladder cancer in the U.S. Only about 7% of kidney cancers (including cancers in your renal pelvis and ureters) are urothelial carcinoma.

Urothelial carcinoma in your bladder or kidney causes similar symptoms. They also have similar prognoses. Caught early, these cancers are easily treated. But they often come back.

Symptoms of urothelial carcinoma

Symptoms may not show up right away. Blood in your pee (hematuria) is usually the first noticeable sign. You should contact a healthcare provider if you notice bloody pee or other symptoms, including:

• A lump or mass in your kidney area (your side and back, between your ribs and hips)
• Fatigue
• Painful or frequent urination
• Persistent low back pain
• Unexplained weight loss

Urothelial carcinoma causes

Medical researchers aren’t sure exactly what causes urothelial carcinoma. But they do know that it involves changes in a specific type of cell.

Your bladder, ureters and renal pelvis (the part of your kidney that connects with your ureters) are lined with urothelial cells. They’re also called “transitional cells” because they can stretch when your bladder fills with pee and collapse when it’s empty.

With urothelial carcinoma, a healthy transitional cell changes (mutates) and becomes a cancer cell. The cancer cells can form tumors. Without treatment, the cancer can spread.

Risk factors

Researchers have identified some common risk factors:

• Sex: You’re four times more likely to get bladder cancer if you’re male. Males are also twice as likely to develop kidney cancers.
• Age: Most people diagnosed are over age 65.
• Cigarette smoke: Smoking cigarettes increases your risk of urothelial carcinoma.
• Exposure to certain chemicals: People who work with certain chemicals used in dyes, rubber, leather, paint, textiles and hairdressing supplies may have an increased risk.
• Medical history: You’re at an increased risk of transitional cell carcinoma of your renal pelvis and ureters if you’ve had bladder cancer.

You might reduce your risk of developing these cancers by not smoking and avoiding certain chemicals.

How doctors diagnose this condition

Healthcare providers may use the following tests to diagnose bladder and kidney cancer, including urothelial carcinoma. Tests include:

• Urine (pee) tests: Your provider will do a urinalysis on a urine sample. They may also do tests to check for cancer cells in your pee.
• Imaging tests: You may need a CT scan, MRI, PET scan or ultrasound so that your provider can see tumors inside your body. You may need an intravenous pyelogram (IVP). An IVP uses a contrast dye that makes blockages in your kidneys, ureter and bladder stand out on an X-ray.
• Scope tests: Your provider may use a scope with a light and lens to see inside your bladder, kidneys or ureters. They may take tissue samples to test for cancer cells (biopsy).

Cancer staging

Healthcare providers use cancer staging systems to develop treatment plans. Staging helps them know how serious or aggressive the cancer is. There are slight differences between the stages for transitional cell carcinoma in your bladder and transitional cell carcinoma in your kidneys (renal pelvis) and ureters.

Bladder cancer stages

Bladder cancer can be early stage (confined to your bladder lining). Or it can be invasive (penetrating your bladder wall and possibly spreading to nearby organs or lymph nodes):

• Stage I: Cancer is in the lining of your bladder or the connective tissue just below the lining. It hasn’t invaded the main muscle wall of your bladder.
• Stage II: Cancer has spread to the muscle wall of your bladder.
• Stage III: Cancer has spread to the fatty tissue outside of your bladder muscle.
• Stage IV: Cancer has spread from your bladder to your lymph nodes or to other organs or bones.

Healthcare providers may also label bladder cancer as:

• Noninvasive: There may be tumors in a small section of tissue. Or the cancer cells may only be near the surface of your bladder.
• Non-muscle-invasive: This refers to bladder cancer that’s moved deeper into your bladder but hasn’t spread to muscle.
• Muscle-invasive: This bladder cancer has grown into your bladder wall muscle. It may have spread into the fatty layers or tissues on organs outside of your bladder.

Bladder cancer can be high grade or low grade. The higher the grade, the more abnormal the cancer cells look beneath a microscope. Usually, high-grade urothelial cancer is more aggressive.

• High-grade urothelial carcinoma may be life-threatening. It often comes back after treatment. It may spread into the muscle layer of your bladder, to other areas in your body and to your lymph nodes.
• Low-grade urothelial carcinoma may come back but rarely spreads into your bladder’s muscle layer or other body parts.

Renal pelvis and ureter cancer stages

The staging for your kidneys and ureters relates to how much the cancer has grown into tissue or spread. Early-stage transitional cell carcinoma is usually low grade. More advanced stages tend to be high grade.

• Stage 0: There are abnormal cells in tissue lining your renal pelvis or ureter. This cancer stage may be called papillary carcinoma or carcinoma in situ.
• Stage 1: Cancer has spread through the lining of your renal pelvis or ureter into a layer of connective tissue.
• Stage II: Cancer has spread through connective tissue to your renal pelvis or ureter’s layer of muscle.
• Stage III: Cancer has spread into the fatty layer beyond the muscle of your renal pelvis or ureter.
• Stage IV: Cancer has spread to nearby organs, one or more lymph nodes, the layer of fat around your kidney, or more distant organs.

How is urothelial carcinoma treated?

Treatment varies depending on whether urothelial carcinoma is in your bladder, kidney or ureters.

Bladder cancer treatment

Treatments for bladder cancer include:

• Surgery: Surgeons either remove the tumor or use high-energy electricity to burn it away. This burning process is called fulguration.
• Chemotherapy: You may take a combination of chemotherapy drugs that treat cancer throughout your body. Sometimes, providers inject the drugs directly into your bladder.
• Immunotherapy: This treatment makes your immune system better at fighting cancer. Your provider may inject a drug called BCG directly into your bladder.
• Radiation therapy: You may need this treatment instead of surgery. Or you may get radiation in addition to other treatments.
• Targeted therapy: This treatment targets the gene changes that cause healthy transitional cells to become cancer cells.

Renal pelvis and ureter cancer treatment

The primary treatment is surgery. Healthcare providers are studying new treatments for transitional cell carcinoma in clinical trials. A clinical trial is a study that tests the safety and effectiveness of new treatments.

Current treatments being tested use heat from electricity or lasers to destroy tumors.

When should I see my healthcare provider?

Contact your provider if you have changes in your body that may mean urothelial cancer in your urinary system has come back. Ask them about signs to look out for.

What is the life expectancy for urothelial carcinoma?

The same cancerous cell causes all of these cancers. But each type has a different prognosis or expected outcome. A lot depends on the stage and grade of urothelial carcinoma. As with many types of cancer, early detection and treatment increase your likelihood of living longer.

Data from the National Cancer Institute (NCI) show that nearly 98% of people who received treatment for early-stage bladder cancer between 2015 and 2021 were alive five years after diagnosis. Overall, 79% of people with bladder cancer were alive five years later.

NCI data show that 93% of people treated for early-stage kidney cancer (including urothelial carcinoma) were alive five years after diagnosis. The overall five-year survival rate is nearly 77%.

It’s important to remember that these numbers reflect the outcomes of lots of people with situations different from yours. They can’t predict your outcomes. Ask your provider about how your diagnosis will impact your life expectancy.

Is there anything I can do to feel better?

It may help to know that carcinoma caught early on responds well to treatment. Still, these types of cancer can come back. Talk to your provider so you know what signs to look out for that mean the cancer has recurred. Be sure not to skip follow-up appointments.