Grading (tumors)

 ( Cancer Pathology ) 

In pathology, grading is a measure of the cell appearance in and other . Some pathology grading systems apply only to malignant neoplasms (cancer); others apply also to benign neoplasms. The neoplastic grading is a measure of cell anaplasia (reversion of differentiation) in the sampled tumor and is based on the resemblance of the tumor to the tissue of origin. Grading in cancer is distinguished from cancer staging, which is a measure of the extent to which the cancer has metastasis.

Pathology grading systems classify the microscopic cell appearance abnormality and deviations in their rate of growth with the goal of predicting developments at tissue level (see also the 4 major histological changes in dysplasia).

Cancer is a disorder of cell cycle alteration that leads (non-trivially) to excessive cell proliferation rates, typically longer cell lifespans and poor differentiation. The grade score (numerical: G1 up to G4) increases with the lack of cellular differentiation - it reflects how much the tumor cells differ from the cells of the normal tissue they have originated from (see 'Categories' below). Tumors may be graded on four-tier, three-tier, or two-tier scales, depending on the institution and the tumor type.

The histology tumor grade score along with the metastasis (whole-body-level cancer-spread) staging are used to evaluate each specific cancer patient, develop their individual treatment strategy and to predict their prognosis. A cancer that is very poorly differentiated is called anaplastic.

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Categories Grading systems are also different for many common types of cancer, though following a similar pattern with grades being increasingly malignant over a range of 1 to 4. If no specific system is used, the following general grades are most commonly used, and recommended by the American Joint Commission on Cancer and other bodies: National Cancer Institute, "Tumor Grade", accessed 18 August, 2014

• GX Grade cannot be assessed
• G1 Well differentiated (Low grade)
• G2 Moderately differentiated (Intermediate grade)
• G3 Poorly differentiated (High grade)
• G4 Undifferentiated (High grade)

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Specific systems Of the many cancer-specific schemes, the Gleason system, named after Donald Floyd Gleason, used to grade the adenocarcinoma cells in prostate cancer is the most famous. This system uses a grading score ranging from 2 to 10. Lower Gleason scores describe well-differentiated less aggressive tumors.

Other systems include the Bloom-Richardson grading system for breast cancer and the Fuhrman system for kidney cancer. Invasive-front grading is useful as well in oral squamous cell carcinoma.Sawair FA, Irwin CR, Gordon DJ, Leonard AG, Stephenson M, Napier SS. Invasive front grading: reliability and usefulness in the management of oral squamous cell carcinoma. J Oral Pathol Med. 2003 Jan;32(1):1-9.

For soft-tissue sarcoma two histological grading systems are used : the National Cancer Institute (NCI) system and the French Federation of Cancer Centers Sarcoma Group (FNCLCC) system.Free full text

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Examples of grading schemes

+ Four-tier grading scheme

Well-differentiated

Moderately differentiated

Poorly differentiated

Anaplastic

+ Three-tier grading scheme

Well-differentiated

Poorly differentiated

+ Two-tier grading scheme

Well-differentiated

Poorly differentiated

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See also

• TNM staging system (Other parameters)
• Tumor kinds that have their own grading system:
• Teratoma
• Gleason score

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External links

• CancerWeb
• Atlas Interactif de Neuro-Oncologie

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