TUMOR STAGING AND GRADING
A complete diagnostic evaluation includes identifying the stage and grade of the tumor. This is accomplished before treatment begins to provide baseline data for evaluating outcomes of therapy and to maintain a systematic and consistent approach to ongoing diagnosis and treatment. Treatment options and prognosis are determined on the basis of staging and grading. Staging determines the size of the tumor and the existence of metastasis. Several systems exist for classifying the anatomic extent of disease.
Following are the Imaging Tests Used to Detect Cancer,
Tumor marker identification
Description
Analysis of substances found in blood or other body fluids that are made by the tumor or by the body in response to the tumor
Diagnostic Tests
Breast, colon, lung, ovarian, testicular, prostate cancers
Magnetic resonance imaging (MRI)
Description
Use of magnetic fields and radiofrequency signals to create sectioned images of various body structures
Diagnostic Tests
Neurologic, pelvic, abdominal, thoracic cancers
Computed tomography (CT scan)
Description
Use of narrow beam x-ray to scan successive layers of tissue for a cross-sectional view
Diagnostic Tests
Neurologic, pelvic, skeletal, abdominal, thoracic cancers
Fluoroscopy
Description
Use of x-rays that identify contrasts in body tissue densities; may involve the use of contrast agents
Diagnostic Tests
Skeletal, lung, gastrointestinal cancers
Ultrasonography (ultrasound)
Description
High-frequency sound waves echoing off body tissues are converted electronically into images; used to assess tissues deep within the body
Diagnostic Tests
Abdominal and pelvic cancers
Endoscopy
Description
Direct visualization of a body cavity or passageway by insertion of an endoscope into a body cavity or opening; allows tissue biopsy, fluid aspiration and excision of small tumors; both diagnostic and therapeutic
Diagnostic Tests
Bronchial, gastrointestinal cancers
Nuclear medicine imaging
Description
Uses intravenous injection or ingestion of radioisotope substances followed by imaging of tissues that have concentrated the radioisotopes
Diagnostic Tests
Bone, liver, kidney, spleen, brain, thyroid cancers
Positron emission tomography (PET scan)
Description
Computed cross-sectional images of increased concentration of radioisotopes in malignant cells provide information about biologic activity of malignant cells; help distinguish between benign and malignant processes and responses to treatment
Diagnostic Tests
Lung, colon, liver, pancreatic, breast, esophagus cancers; Hodgkin’s and non-Hodgkin’s lymphoma and melanoma
Radioimmunoconjugates
Description
Monoclonal antibodies are labeled with a radioisotope and injected intravenously into the patient; the antibodies that aggregate at the tumor site are visualized with scanners
Diagnostic Tests
Colorectal, breast, ovarian, head and neck cancers; lymphoma and melanoma
The TNM system is frequently used. In this system, T refers to the extent of the primary tumor, N refers to lymph node involvement, and M refers to the extent of metastasis A variety of other staging systems are used to describe the extent of cancers, such as central nervous system cancers, hematologic cancers, and malignant melanoma, that the TNM system does not describe appropriately. Staging systems also provide a convenient shorthand notation that condenses lengthy descriptions into manageable terms for comparisons of treatments and prognoses. Grading refers to the classification of the tumor cells. Grading systems seek to define the type of tissue from which the tumor originated and the degree to which the tumor cells retain the.
