Primary tumor (T)

• TX: Primary tumor cannot be assessed
  
• T0: No evidence of primary tumor
  
• T1: Clinically inapparent tumor not palpable nor visible by imaging
  • T1a: Tumor incidental histologic finding in 5% or less of tissue resected
  • T1b: Tumor incidental histologic finding in more than 5% of tissue resected
  • T1c: Tumor identified by needle biopsy (e.g., because of elevated PSA)
    
• T2: Tumor confined within prostate*
  • T2a: Tumor involves 50% or less of one lobe
  • T2b: Tumor involves more than 50% of one lobe but not both lobes
  • T2c: Tumor involves both lobes
    
• T3: Tumor extends through the prostate capsule**
  • T3a: Extracapsular extension (unilateral or bilateral)
  • T3b: Tumor invades seminal vesicle(s)
    
• T4: Tumor is fixed or invades adjacent structures other than seminal vesicles: bladder neck, external sphincter, rectum, levator muscles, and/or pelvic wall
  

* [Note: Tumor that is found in one or both lobes by needle biopsy but is not palpable or reliably visible by imaging is classified as T1c.]

** [Note: Invasion into the prostatic apex or into (but not beyond) the prostatic capsule is classified as T2 not T3.]

Regional lymph nodes (N)

• Regional lymph nodes are the nodes of the true pelvis, which essentially are the pelvic nodes below the bifurcation of the common iliac arteries. They include the following groups (laterality does not affect the N classification): pelvic (not otherwise specified [NOS]), hypogastric, obturator, iliac (i.e., internal, external, or NOS), and sacral (lateral, presacral, promontory [e.g., Gerota’s], or NOS). Distant lymph nodes are outside the confines of the true pelvis. They can be imaged using ultrasound, CT, MRI, or lymphangiography and include: aortic (para-aortic, periaortic, or lumbar), common iliac, inguinal (deep), superficial inguinal (femoral), supraclavicular, cervical, scalene, and retroperitoneal (NOS) nodes. Although enlarged lymph nodes can occasionally be visualized, because of a stage migration associated with PSA screening, very few patients will be found to have nodal disease, so false-positive and false-negative results are common when imaging tests are employed. In lieu of imaging, risk tables are generally used to determine individual patient risk of nodal involvement. Involvement of distant lymph nodes is classified as M1a.
  • NX: Regional lymph nodes were not assessed
  • N0: No regional lymph node metastasis
  • N1: Metastasis in regional lymph node(s)

Distant metastasis (M)*

• MX: Distant metastasis cannot be assessed (not evaluated by any modality)
• M0: No distant metastasis
• M1: Distant metastasis
  • M1a: Nonregional lymph node(s)
  • M1b: Bone(s)
  • M1c: Other site(s) with or without bone disease

* [Note: When more than one site of metastasis is present, the most advanced category (pM1c) is used.]

Histopathologic grade (G)

• GX: Grade cannot be assessed
• G1: Well-differentiated (slight anaplasia) (Gleason score of 2–4)
• G2: Moderately differentiated (moderate anaplasia) (Gleason score of 5–6)
• G3-4: Poorly differentiated or undifferentiated (marked anaplasia) (Gleason score of 7–10)