Non muscle invasive bladder cancer staging

Non muscle invasive bladder cancer means the cancer cells are only in the inner lining of the bladder. They have not grown through the inner lining and into the deeper muscle layer of the bladder. It is early in its development.

Doctors used to call this superficial bladder cancer. It is different to muscle invasive bladder cancer, where the cancer has grown into the deeper muscle layer.

The stage of your cancer describes how far your cancer has grown. This page is about the stages of non muscle invasive bladder cancer.

The stages of non muscle invasive bladder cancer

Doctors diagnose the stage of your bladder cancer by looking at how far tumours have grown into the bladder. This is called the T stage. There are 3 T stages of non muscle invasive bladder cancer:

  • Tis or CIS (also called carcinoma in situ)
  • Ta
  • T1

Doctors also look at the cells under the microscope. This tells them the grade. The grade means how much the cells look like normal cells. 

CIS or Tis

Carcinoma in situ (also called CIS or Tis) means there are very early cancer cells in the inner layer of the bladder lining. The cancer cells look very abnormal and are likely to grow quickly. This is called high grade.

CIS can grow in more than one place in the bladder lining. It looks like flat velvety patches through a microscope.


The tumour is only in the innermost layer of the bladder lining (Ta). These tumours often look like small mushrooms growing out of the bladder wall.


The cancer has started to grow into the connective tissue beneath the bladder lining. 

Diagram showing non-muscle invasive bladder cancer

When staging bladder cancer, doctors also look at whether the cancer has spread to:

  • any lymph nodes (this is called the N stage)
  • other parts of the body (distant metastasis) like the bones, lungs or liver (this is called the M stage)

Risk groups for non muscle invasive bladder cancer

Doctors put non muscle invasive bladder cancer into 3 risk groups. These groups describe how likely it is that your cancer will spread further, or come back after treatment.

The 3 risk groups are:

  • low risk
  • intermediate (medium) risk
  • high risk

Your doctor tells you whether your cancer is low risk, intermediate (medium) risk or high risk. Knowing your risk group helps them decide which tests and treatment are best for you.

Your risk group depends on:​​

  • the size of your tumour (T stage)
  • what the cells look like under a microscope (grade)
  • whether you have any carcinoma in situ (CIS)
  • how many tumours there are
  • how wide the tumour is (diameter)
  • whether this is your first diagnosis, or it has come back (a recurrence)


The stage of your cancer helps your doctor to decide which treatment you need. Treatment also depends on:

  • your type of cancer (the type of cells the cancer started in)
  • your risk group (low, intermediate or high)
  • where the cancer is
  • other health conditions

Treatment may include:

  • surgery
  • chemotherapy into your bladder
  • a vaccine called BCG into your bladder
  • American Joint Committee on Cancer (AJCC) manual (8th edition)
    S Edge and others
    Springer, 2017​

  • Bladder cancer: diagnosis and management of bladder cancer
    National Institute of Health and Clinical Excellence, 2015

  • Bladder cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up.
    T Powles and others
    Annals of oncology, 2022 Volume 33, Issue 3, Page 244 - 258

  • European Guidelines on Non-muscle-invasive Bladder Cancer (TaT1 and CIS)
    M Babjuk and others
    European Association of Urology, 2022

  • Bladder cancer: Overview and disease management. Part 1: non-muscle-invasive bladder cancer
    B Anderson
    British Journal of Nursing, 2018. (Urology Supplement) Volume 27, Issue 9, Pages 27-37

  • Management of carcinoma in situ of the bladder: best practice and recent developments
    D H Tang and S S Chang
    Therapeutic Advances in Urology, 2015. Volume 7, Issue 6, Pages 351 – 364

Last reviewed: 
07 Mar 2023
Next review due: 
07 Mar 2026

Related links