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A biopsy takes a small segment of the abnormal tissue and the pathologist examines this under the microscope. In case, the lesion is very small, the whole lesion may also be completely excised, for a proper analysis. Lip biopsy is usually done under local anesthesia.
Biopsy of any tissue, is the definitive diagnostic procedure, which provides information regarding the stage and the grade of the cancer.
The stage of a cancer is a measure of how much the cancer has grown and spread.
Tumor grade is a system used to classify cancer cells in terms of how abnormal they look under a microscope and how quickly the tumor is likely to grow and spread.
Based on the above information, the proper treatment needed will be decided by your doctor.