TNM classification

TNM classification

Oncology An international system for staging malignancy which measures 3 major parameters of a cancer: T–size or extent of the primary tumor, as determined by clinical exam, endoscopy, laparoscopy, biopsy or resective procedures, categorized as being 1-4 and a-d depending upon site, size, and spread; N–number of involved lymph nodes, categorized as X–unknown status, 0–none identified, 1–one to several, 2–a whole bunch of positive LNs; M-X, unknown presence or absence of metastases. See Staging.

TNM classification for staging malignancy

T Tumor

Tis    Carcinoma in situ

Ta  Non-invasive

Tx   Cannot be evaluated for nonspecified reasons

T0  Localized tumor

T1  Lesion extends to muscle–bladder, colon, breast

      T1a < 0.5 cm in greatest dimension

  T1b < 1.0 cm in greatest dimension

  T1c < 2.0 cm in greatest dimension

T2  Invasion into muscle

T3  Persistent induration of organ after resection

   T3a Invasion to deep muscle

   T3b Invasion through the organ

T4  Tumor invasion or fixation

   T4a Adjacent organ invasion

   T4b Fixation to bladder or colonic wall; in breast, edema

N Nodes

N0  No lymph node metastasis

N1  One regional lymph node metastasis

N2  Multiple, mobile regional lymph node metastases

N3  Fixed regional lymph node metastases

N4  Beyond regional lymph node involvement

NX  Lymph nodes, not evaluable

M Metastasis

M0 No evidence of metastases

M1  Distant metastases are present

MX Distant metastases not evaluable