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TNM classificationOncology 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
Tis Carcinoma in situ
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
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
M0 No evidence of metastases
M1 Distant metastases are present
MX Distant metastases not evaluable
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
A method of classifying malignant tumors with respect to primary tumor, involvement of regional lymph nodes, and presence or absence of metastases.
See also: classification
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