What Is the Prostate Cancer TNM Stage?

Last Editorial Review: 1/11/2018

Ask the experts

We have been diagnosed as having prostate cancer, which is in the B1 stage. These stages are A, B, C, and D. Now there is a new stage system and we are classified as T2A. We would like to obtain the entire new stage classification. Also, our Primary Care Physician will obtain from us a PFT and a CXR. We would like to know what these abbreviations mean before we go to our appointment in order to have a better understanding of what is going on because our doctors always seem to be in a rush. We have tried accessing Medical Dictionaries, the AMA Encyclopedia of Medicine and a nursing manual all to no avail. No doubt it is there but one needs to know the meaning of the abbreviation before it can be found.

Doctor's response

CXR stands for chest X-ray. PFT stands for pulmonary function testing.

The TNM staging system refers to Tumor, Nodes, Metastasis. The full explanation is below. A T2a tumor indicates that it involves half of the prostate or less. At the stage of the workup you describe, the lymph node status or possibility of metastatic disease would not be known.

For more information, read our full medical article on prostate cancer:

  • TX: Primary tumor cannot be assessed
  • T0: No evidence of primary tumor
  • T1: Clinically inapparent tumor not palpable or 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: Palpable tumor confined within prostate *
  • T2a: Tumor involves half of a lobe or less
  • T2b: Tumor involves more than half of a lobe, but not both lobes
  • T2c: Tumor involves both lobes
  • T3: Tumor extends through the prostatic capsule
  • T3a: Unilateral extracapsular extension
  • T3b: Bilateral extracapsular extension
  • T3c: Tumor invades seminal vesicle(s)
  • T4: Tumor is fixed or invades adjacent structures other than seminal vesicles
  • T4a: Tumor invades external sphincter and/or bladder neck and/or rectum
  • T4b: Tumor invades levator muscles and/or is fixed to pelvic wall*

* Note: Tumor found in one or both lobes by needle biopsy, but not palpable or visible by imaging, is classified as T1 c.

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

  • NX: Regional lymph nodes cannot be assessed
  • NO: No regional lymph node metastasis
  • N1: Metastasis in a single lymph node, 2 cm or less in greatest dimension
  • N2: Metastasis in a single lymph node, more than 2cm but not more than 5 cm in greatest dimension, or multiple lymph nodes, none more than 5 cm in greatest dimension N3 Metastasis in a lymph node more than 5 cm in greatest dimension
  • MX: Presence of distant metastasis cannot be assessed
  • MO: No distant metastasis
  • M1: Distant metastasis
  • M1a: Non­ regional lymph nodes
  • M1b: Bone
  • M1c: Other sites

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