Bladder cancer staging describes the extent to which cancer has spread within the bladder or to other parts of the body. The most commonly used staging system is the TNM system, which stands for Tumor, Nodes, and Metastasis. Here is an overview:

TNM Staging System

1. Tumor (T)
   • Tis (Carcinoma in situ): Cancer cells are only in the inner lining of the bladder.
   • Ta: Non-invasive papillary carcinoma; cancer is in the inner lining but has not invaded deeper tissues.
   • T1: Tumor has invaded the connective tissue beneath the lining but not the muscle layer.
   • T2: Tumor has invaded the muscle layer of the bladder.
     • T2a: Tumor has invaded the inner half of the muscle layer.
     • T2b: Tumor has invaded the outer half of the muscle layer.
   • T3: Tumor has spread through the muscle layer to the surrounding fatty tissue.
     • T3a: Microscopic invasion into the fatty tissue.
     • T3b: Macroscopic invasion into the fatty tissue.
   • T4: Tumor has spread to surrounding organs and structures.
     • T4a: Tumor has invaded the prostate, uterus, or vagina.
     • T4b: Tumor has invaded the pelvic or abdominal wall.
2. Nodes (N)
   • N0: No regional lymph node involvement.
   • N1: Cancer has spread to a single lymph node in the pelvic region.
   • N2: Cancer has spread to multiple lymph nodes in the pelvic region.
   • N3: Cancer has spread to lymph nodes along the common iliac artery.
3. Metastasis (M)
   • M0: No distant metastasis.
   • M1: Distant metastasis is present.
     • M1a: Cancer has spread to distant lymph nodes beyond the pelvic area.
     • M1b: Cancer has spread to other distant organs, such as the liver, bones, or lungs.

Staging Groups

The TNM information is combined to classify bladder cancer into stages:

• Stage 0: Tis or Ta, N0, M0
• Stage I: T1, N0, M0
• Stage II: T2, N0, M0
• Stage III: T3 or T4a, N0, M0
• Stage IV: T4b, N0, M0 or any T, N1-3, M0 or any T, any N, M1

Grades of Bladder Cancer

The grade of bladder cancer refers to how much the cancer cells look like normal cells under a microscope, indicating how quickly the cancer is likely to grow and spread.

1. Low-Grade (Grade 1)
   • Cancer cells look more like normal cells and tend to grow slowly.
   • Sources: American Cancer Society, National Cancer Institute
2. High-Grade (Grade 2 and Grade 3)
   • Cancer cells look more abnormal and are more likely to grow and spread quickly.
   • Sources: American Cancer Society, Mayo Clinic

Understanding the stage and grade of bladder cancer is crucial for determining the most appropriate treatment options and predicting the likely course of the disease. For more detailed information, you can visit:

• American Cancer Society: Bladder Cancer Staging
• National Cancer Institute: Bladder Cancer Treatment (PDQ®)–Patient Version
• Mayo Clinic: Bladder Cancer Diagnosis