Staging of prostate cancer
The tumor classification applies only to adenocarcinomas. Urethral cancer (transitional cell carcinoma) is classified as a tumor in the urethra (1).
The TNM-system describes how the disease has spread and at what time it is evident. “T” describes the spread of the local tumor in and around the prostate. “N” (node) expresses if it has spread to the lymph nodes. “M” expresses distant metastases.
The TNM-classification system differentiates between clinical classification (TNM) and pathology classification (pTNM). TNM is based on the clinical examination of the primary report. This includes manual palpation of the prostate via the rectum (preferably under local anesthesia), transrectal ultrasound (TRUS) and possibly other image diagnostic investigations (CT, MRI), demarcation biopsies, and gland staging. According to the international TNM standard, TRUS and MRI contribute to the classification, but TRUS is a good supplement for stage determination. MRI will likley develop over time, but at present time it is not documented to be of great value.
T1 and T2 correspond to localized disease. T3 and T4 correspond to locally advanced disease.
TX: Primary tumor not assessed.
T0: Primary tumor not evident.
T1: No evidence of tumor by palpation, ultrasound, or other radiological method but cancer is evident by prostate biopsy.
- T1a: Tumor in ≤ 5% of investigated tissue by TUR-P (Transurethral Resection of the Prostate)
- T1b: Tumor in > 5% of investigated tissue by TUR-P
- T1c: Tumor evidence by needle biopsy (for example by raised PSA)
T2: Palpable or visible tumor limited to prostate the gland
- T2a: Tumor includes ≤ ½ of one lobe
- T2b: Tumor includes > ½ of one lobe
- T 2c: Tumor bilateral
T3: Extracapsular tumor growth
NB: Growth in apex of prostate or in (but not through) the prostate capsule classifies as T2.
- T3a: Extracapsular tumor growth (unilateral or bilateral), including microscopic bladder neck invasion.
- T3b: Tumor infiltration into seminal vesicles
T4: The tumor is fixed to or is growing into surrounding structures (bladder, anal sphincter, rectum, levator musculature, and/or is fixed to the pelvic wall).
N0: No known spread to the lymph nodes.
N1: Regional lymph node spreading
M0: No known distant metastases
M1: Distant metastases