In pathology, grading is a measure of the cell appearance in tumors and other neoplasms. 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.[1] Grading in cancer is distinguished from staging, which is a measure of the extent to which the cancer has spread.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Histologic_geographic_variability_of_diffuse_intrinsic_pontine_glioma_%28DIPG%29_-_Fonc-02-00205-g003_%28cropped%29.jpg/220px-Histologic_geographic_variability_of_diffuse_intrinsic_pontine_glioma_%28DIPG%29_-_Fonc-02-00205-g003_%28cropped%29.jpg)
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 life 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 histologic tumor grade score along with the metastatic (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.
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:[2]
- GX Grade cannot be assessed
- G1 Well differentiated (Low grade)
- G2 Moderately differentiated (Intermediate grade)
- G3 Poorly differentiated (High grade)
- G4 Undifferentiated (High grade)
Specific systems
Of the many cancer-specific schemes, the Gleason system,[3] 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.[4]
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.[5][6]
Examples of grading schemes
Grade 1 | Low grade | Well-differentiated |
Grade 2 | Intermediate grade | Moderately differentiated |
Grade 3 | High grade | Poorly differentiated |
Grade 4 | Anaplastic | Anaplastic |
Grade 1 | Low grade | Well-differentiated |
Grade 2 | Intermediate grade | |
Grade 3 | High grade | Poorly differentiated |
Grade 1 | Low grade | Well-differentiated |
Grade 2 | High grade | Poorly differentiated |
See also
- TNM staging system (Other parameters)
- Tumor kinds that have their own grading system:
- Gleason score
References
External links
- CancerWeb Archived 2002-04-30 at the Wayback Machine
- Atlas Interactif de Neuro-Oncologie