The clinical staging of carcinoma of the bladder is determined by the depth of invasion of the bladder wall by the tumor. This determination requires a cystoscopic examination that includes a biopsy, and examination under anesthesia to assess the size and mobility of palpable masses, the degree of induration of the bladder wall, and the presence of extravesical extension or invasion of adjacent organs. Clinical staging, even when computed tomographic and/or magnetic resonance imaging scans and other imaging modalities are used, often underestimates the extent of tumor, particularly in cancers that are less differentiated and more deeply invasive.[1,2,3]

The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification to define bladder cancer.[4]

TNM Definitions

Primary tumor (T)

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• Ta: Noninvasive papillary carcinoma
• Tis: Carcinoma in situ (i.e., flat tumor)
• T1: Tumor invades subepithelial connective tissue
• T2: Tumor invades muscle
  • pT2a: Tumor invades superficial muscle (inner half)
  • pT2b: Tumor invades deep muscle (outer half)
• T3: Tumor invades perivesical tissue
  • pT3a: Microscopically
  • pT3b: Macroscopically (extravesical mass)
• T4: Tumor invades any of the following: prostate, uterus, vagina, pelvic wall, or abdominal wall
  • T4a: Tumor invades the prostate, uterus, vagina
  • T4b: Tumor invades the pelvic wall, abdominal wall

The suffix "m" should be added to the appropriate T category to indicate multiple lesions. The suffix "is" may be added to any T to indicate the presence of associated carcinoma in situ.

Regional lymph nodes (N)

• NX: Regional lymph nodes cannot be assessed
• N0: No regional lymph node metastasis
• N1: Metastasis in a single lymph node 2 cm or smaller in largest dimension
• N2: Metastasis in a single lymph node larger than 2 cm but 5 cm or smaller in largest dimension; or multiple lymph nodes 5 cm or smaller in largest dimension
• N3: Metastasis in a lymph node larger than 5 cm in largest dimension

Distant metastasis (M)

• MX: Distant metastasis cannot be assessed
• M0: No distant metastasis
• M1: Distant metastasis

AJCC Stage Groupings

Stage 0a

• Ta, N0, M0

Stage 0is

• Tis, N0, M0

Stage I

• T1, N0, M0

Stage II

• T2a, N0, M0
• T2b, N0, M0

Stage III

• T3a, N0, M0
• T3b, N0, M0
• T4a, N0, M0

Stage IV

• T4b, N0, M0
• Any T, N1, M0
• Any T, N2, M0
• Any T, N3, M0
• Any T, any N, M1

An older, less frequently used staging system was derived by comparing clinical estimates of stage with the pathologic stage of radical cystectomy specimens.[2,3] To better ensure uniform staging and reporting of clinical results, the use of the modern TNM classification described above is recommended.

References:

1. Consensus conference. Magnetic resonance imaging. JAMA 259 (14): 2132-8, 1988.
2. Marshall VF: The relationship of the preoperative estimate to the pathologic demonstration of the extent of vesical neoplasms. J Urol 68(4): 714-723, 1952.
3. Skinner DG: Current state of classification and staging of bladder cancer. Cancer Res 37 (8 Pt 2): 2838-42, 1977.
4. Urinary bladder. In: American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002, pp 335-340.