cancer grading and staging

cancer grading and staging

The standardized procedure for expressing cancer cell differentiation, called grading, and the extent of dissemination of the cancer, called staging. This procedure is very helpful in comparing the results of various forms of therapy. Cancer is graded on the differentiation of the tumor cells and the number of mitoses present. These are thought to be correlated with the ability of the tumor to grow and spread. Some cancers are graded I to IV, the latter being the most anaplastic and having the least resemblance to normal tissue.

Cancers are staged according to size, amount of local spread (metastases), and whether blood-borne metastasis has occurred. There are two major staging systems. The TNM judges the size of primary tumor (T), evidence of regional extension or nodes (N), and evidence of metastases (M). Another system classifies cancers as Stage 0 to IV according to the size of the tumor and its spread.

It is not possible to determine the site of the primary malignancy for some metastatic cancers. The most frequent cell types are adenocarcinoma, melanoma, lymphoma, sarcoma, and squamous cell carcinoma. Even though the prognosis is poor for affected patients, their response may be improved if the cell type is specifically identified.

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