hematology and oncology
Cancer Diagnosis
Testing
Tests include imaging tests, biomarkers, and biopsies; one or more of which may be indicated in patients with a suggestive history or physical or laboratory findings. Imaging testsinclude plain x-rays, ultrasonography, CT, positron emission tomography (PET), and MRI studies. These tests assist in identifying abnormalities, determining qualities of a mass (solid or cystic), providing dimensions, and establishing relationship to surrounding structures, which may be important if surgery or biopsy is being considered. may offer corroborating evidence in patients with findings suggestive of a specific cancer (see Tumor Immunodiagnosis ). Most are not used as routine screening tests, except in high-risk patients. Useful examples include Alpha-fetoprotein ( Hepatocellular Carcinoma , Carcinoembryonic antigen ( Colorectal Cancer ) Beta-human chorionic gonadotropin(choriocarcinoma, testicular carcinoma) Serum immunoglobulins ( Multiple Myeloma ) Molecular tests (diverse cancers) CA 125 ( Ovarian, Fallopian Tube, and Peritoneal Cancer ) CA 27-29 ( Breast Cancer ) PSA (prostate-specific antigen— Prostate Cancer ) Some of these biomarkers may be most useful in monitoring the response to treatment rather than in tumor detection. Biopsyto confirm the diagnosis and tissue of origin is almost always required when cancer is suspected. The choice of biopsy site is usually determined by ease of access and degree of invasiveness. If lymphadenopathy is present, fine-needle or core biopsy may reveal the cancer type. Core biopsies or lymph node excision are recommended for diagnosis of lymphomas because preservation of nodal architecture is important for accurate histologic diagnosis. Sometimes an open biopsy is needed. Other biopsy routes include bronchoscopy or mediastinoscopy for easily accessible mediastinal or central pulmonary tumors, percutaneous liver biopsy if liver lesions are present, and CT- or ultrasound-guided biopsy of lung or soft tissue masses. Gradingis a histologic measure of cancer aggressiveness and provides important prognostic information. It is determined by examining the tissue specimen. Grade is based on the morphologic appearance of cancer cells, including the appearance of the nuclei, cytoplasm, and nucleoli; frequency of mitoses; and amount of necrosis. For many cancers, grading scales have been developed. Molecular testssuch as chromosomal analysis, fluorescentin situhybridization (FISH), polymerase chain reaction (PCR), and cell surface antigen testing (eg, in lymphomas, leukemias, lung, and gastrointestinal cancers) help delineate the origin of metastatic cancers, particularly for cancers of unknown primary origin, and may be helpful in selecting therapy. 