Finding out you have bladder cancer can feel overwhelming. Carcinoma in situ (CIS) is an early form of bladder cancer, but it has a higher chance of coming back after treatment or spreading to a more advanced stage.

Learning the facts about CIS can help you understand your diagnosis and know what to expect. In this article, we’ll review the basic facts about CIS bladder cancer to give you a clearer understanding of what it is, how it’s treated, and what it may mean for the future.

1. CIS Hasn’t Spread From the Inner Lining of the Bladder

Like most types of bladder cancer, CIS begins in the cells that line the innermost layer of the bladder, called the urothelium. The term “in situ” means “in its original place,” so the cancer hasn’t spread deeper into the bladder wall or to other parts of the body. CIS is a term also used in other types of cancer. In bladder cancer, CIS is classified as non-muscle-invasive bladder cancer (NMIBC) because it stays in the lining and hasn’t reached the muscle layer.

Which Stage of Cancer Is Called in Situ?

CIS is the earliest stage of bladder cancer, also known as stage 0. The two subtypes of bladder cancer in stage 0 are CIS and noninvasive papillary carcinomas.

CIS is a flat, noninvasive carcinoma. Instead of forming a lump, it spreads like a thin sheet along the surface of the urothelium, not inward toward the hollow part of the bladder.

Noninvasive papillary carcinomas are also considered a type of stage 0 bladder cancer, but they look and grow differently from CIS bladder cancer. This subtype grows toward the hollow part of the bladder in thin, finger-like projections.

2. CIS Makes Up About 10 Percent of NMIBC Cases

The American Cancer Society estimates that almost 85,000 people in the United States will be diagnosed with bladder cancer in 2025.

Between 75 percent and 80 percent of all bladder cancers are NMIBC. Of people diagnosed with NMIBC, about 10 percent have CIS bladder cancer. This means that about 6,400 to 6,800 people in the U.S. are expected to be diagnosed with CIS.

3. Frequent, Urgent, or Painful Urination Is a Common Symptom

The most common symptom of bladder cancer is hematuria, blood in the urine. Many people have blood in the urine without any other uncomfortable symptoms, especially in those with early-stage bladder cancer. Additional symptoms are usually more common in people with more advanced bladder cancer.

Carcinoma in situ bladder symptoms can vary. Its symptoms depend on its size and location. Even though it’s an early-stage cancer, it’s common for people with CIS to have additional bothersome and uncomfortable urinary symptoms, such as:

• Painful urination
• Frequent urination
• Feeling a sudden, urgent need to urinate
• Urge incontinence (urine leaking suddenly)

4. CIS Is a High-Grade Bladder Cancer

Bladder cancers are given a grade based on how abnormal the cancer cells look under the microscope. Knowing the grade helps your cancer care team understand how your cancer may progress and which treatments might work best.

Low-grade bladder cancer cells look more like normal bladder cells. They tend to grow more slowly and are more likely to stay in the lining of the bladder.

High-grade bladder cancer cells look very abnormal compared to normal bladder cells. This type of cancer is more likely to grow quickly, spread to the muscle layer of the bladder, and come back after treatment.

By definition, CIS bladder cancer is always considered to be high-grade bladder cancer. Because of this, your cancer care team may recommend more aggressive bladder cancer treatments, even though it’s an early-stage cancer.

5. Urine Cytology Can Help Diagnose CIS

Urine cytology is a simple test for bladder cancer. It involves using a microscope to look for cancer cells in a sample of urine.

Urine cytology can be especially helpful for finding high-grade cancers, like CIS. As a high-grade tumor, CIS cancer cells look different from normal bladder cells. That means it’s easier to spot these abnormal bladder cells under the microscope.

Finding abnormal cells in a urine cytology test usually makes healthcare providers suspicious of CIS bladder cancer. You’ll need additional testing to diagnose CIS bladder cancer.

6. Carcinoma in Situ Bladder Cancer Can Be Difficult To Find

If your healthcare provider suspects bladder cancer — for example, after a positive urine cytology test result — they may do a cystoscopy to look directly inside your bladder. This procedure involves inserting a thin tube with a camera into your bladder through your urethra (the tube that carries urine out of your body) to look for abnormal areas on the bladder wall.

CIS bladder cancer often looks like a flat, red, velvety patch on the bladder wall, but it’s not always easy to see with cystoscopy. Finding all areas of CIS is important to make sure all tumors are removed during transurethral resection of bladder tumor (TURBT).

To help find all CIS tumors, healthcare providers can use a technique called fluorescence cystoscopy. For this test, they’ll put a light-activated drug into your bladder that’s absorbed by cancer cells. Under blue light, the cancer cells glow bright pink, making it easier to find CIS. This method can help detect more CIS tumors and reduce the risk of recurrence.

7. BCG Treatment Can Help Prevent CIS From Coming Back

CIS bladder cancer can involve a large area of the lining of the bladder, so it may not be possible to remove all cancer cells using TURBT. Intravesical immunotherapy (medication delivered directly to the bladder through a catheter) after TURBT can help reduce the risk that bladder cancer will return.

Bacillus Calmette-Guérin (BCG) is the most common type of intravesical therapy for CIS. BCG is a vaccine that helps activate the immune system to fight cancer cells. BCG treatment involves putting a liquid BCG directly into the bladder. People with high-risk bladder cancer, like CIS, may continue to receive BCG treatment for up to three years.

If BCG treatment doesn’t work, other treatment options include:

• Radical cystectomy (surgical removal of the entire bladder)
• Intravesical therapy with chemotherapy, particularly gemcitabine
• Immunotherapy

8. CIS Has a High Risk of Spreading or Worsening

Healthcare providers classify bladder cancer as low risk, intermediate risk, high risk, or very high risk of disease progression. The classification considers several factors, including:

• Tumor size
• How far cancer has spread
• Tumor grade
• Type of bladder cancer
• Response to treatment

Doctors classify any CIS bladder cancer as high-risk for disease progression. People diagnosed with CIS may need close follow-up with their cancer care team to make sure the cancer hasn’t progressed or come back after treatment.

What Is the Survival Rate for Carcinoma in Situ?

A survival rate is a way of describing the percentage of people who are still alive after a certain period of time, often five years. While survival rates can’t predict the carcinoma in situ prognosis (outcome) for a specific individual, they can give you a general idea of the likely outcome.

For people with CIS bladder cancer alone, the outlook is positive. According to the National Cancer Institute, 97 percent of people with CIS alone live at least five years after their diagnosis. Talk to your cancer care team to learn more about factors that can affect your prognosis.

Talk With Others Who Understand

On MyBladderCancerTeam, people share their experiences with bladder cancer, get advice, and find support from others who understand.

Have you or a loved one been diagnosed with carcinoma in situ bladder cancer? Let others know in the comments below.