● Oligodendroglial tumors. ● Astrocytic tumors. ● Mixed gliomas. ● Ependymal tumors. ● Pineal parenchymal tumor. ● Meningeal tumors. ● Medulloblastomas ● Germ-cell tumors. ● Craniopharyngiomas.
Cancer Institute states that melanoma of the skin is the fifth most common type of new cancer diagnosed in American men and sixth most common in American women. It is the deadliest form of skin cancer (American Society of Clinical Oncology, 2020). The incidence of skin melanoma has increased by more than 60% over the last 25 years. Intraocular melanoma is a rare form of cancer that forms in the melanocytes in the eye. It may have no early signs or symptoms, but it is sometimes found during an eye exam. Brain and spinal cord tumors that originate in the central nervous system are named based on the type of cell and location. They are different from cancers that start in other areas of the body and metastasize to the brain and spine. The cause of most brain and spinal cord tumors is unknown, but some genetic syndromes may increase the risk. Malignant tumors tend to grow quickly and spread into other areas of the brain or spine. As the tumors grow, they may stop parts of the brain or spinal cord from working. Signs and symptoms may be different for every person. There are many different types of brain and spinal cord tumors, including: Cancer is always described by the stage that it was diagnosed, even if it metastasizes or the tumors grow larger. Once diagnosed, staging cancer helps physicians determine the severity of cancer and the best course of treatment. The stage of cancer is determined using patient history, lab tests, imaging, and biopsy (National Cancer Institute, 2019). Lab tests of blood, urine, and other fluids can be used to measure the levels of certain substances in the body. Abnormally high or low levels of these substances can signal cancer, but they are not a definitive answer. Lab tests are important tools, but physicians must use them together with imaging and other assessment methods to diagnose cancer. Imaging procedures are another important tool in the diagnosis of cancer. In addition to the screening and diagnosis of cancer, imaging studies can help in staging, guiding cancer treatments, determining whether treatments are working, and monitoring for recurrence. Screening for cancer is usually recommended for people who have increased risk, for example, family history of a particular form of cancer. Imaging can be used to determine the stage of cancer by finding the location in the body, the amount present, and whether it has spread to other areas. There are several types of imaging that use different technologies to produce pictures of areas inside of the body: ● X-ray imaging : Uses low-level radiation to produce pictures of the body based on the different absorption rates of various tissues. A common use is to detect bone fractures, because bones have a high absorption rate and appear white on film. X-rays can also be used for early cancer detection as in chest radiographs and mammograms. ● CT scans, or computed tomography scans : Use computer- controlled X-rays to take a series of detailed images of the organs. The image is produced using three-dimensional slices of the body to give more information about the location, size, and depth of tumors. Contrast agents can be injected or taken by mouth to show boundaries between different tissues. ● Nuclear imaging : Including positron emission tomography (PET) and single positron emission computed tomography (SPECT) scans, use low doses of radioactive substances that Stages of cancer Cancer staging helps physicians to determine the extent of cancer and the patient’s potential for survival. It also assists in identifying the appropriate treatment plan and possible clinical trials for new treatment options. The cancer stage is always named by the stage at diagnosis, even if it worsens and spreads to other areas of the body.
Secondary tumors from other metastatic types of cancer can spread to the brain and spine. Examples of this include: ● Breast cancer. ● Colon cancer. ● Kidney cancer. ● Melanoma. ● Nasopharyngeal cancer. ● Lung cancer. ● Lymphoma (Hodgkin and non-Hodgkin lymphoma). ● Leukemia.
TOOLS FOR DIAGNOSING AND STAGING CANCER
attach to tumor cells. Once the tumor cells are marked with these substances, specialized detection equipment is used to create images. PET scans show chemical changes that take place in the tissue. They are usually more accurate in detecting large tumors than tumors smaller than 8 mm. PET scans may be helpful in determining whether the mass is cancerous and staging recurrent cancer. SPECT scans are similar to PET scans; however, they use computer modeling to create two- and three-dimensional images of the body. They can give information about metabolic changes and blood flow. ● Ultrasound : Uses a transducer to produce soundwaves with frequencies higher than those detected by human ears. The soundwaves penetrate tissue in the body and reflect back to the device where a computer uses the echoes to create an image of the organs and tissues. This image is called a sonogram . ● MRI (magnetic resonance imaging) : Uses strong magnetic fields and radio waves to create images of organs and other tissues. It is similar to a CT scan because it can produce three-dimensional images of different sections of the body; however, it is more sensitive for assessing soft tissues. The intensity of the signal produced depends on the chemical makeup of the structures being assessed. MRI can be used with or without contrast to target different tissues. A biopsy is an examination that a pathologist performs on a sample of tissue collected from a patient with suspected cancer. The tissue is viewed under a microscope to determine whether the cells are malignant. Samples can be collected with a needle, an endoscope, or with surgery. For a needle biopsy, the needle penetrates the area of interest and tissue or fluid is drawn into it. If the target tissue is deeper and can be reached through a natural body opening, an endoscope can be used to remove the cells or tissue. Surgical biopsies can be either incisional or excisional. The surgeon removes only part of the tumor during incisional biopsies; however, the entire tumor is removed with excisional biopsies. A biopsy is necessary to diagnose cancer in most cases. Several systems are used to stage cancer, including the TNM staging system. The TNM system can describe cancer in detail and it is the most widely-used system among most medical centers. TNM is an acronym that refers to the main tumor (T), the number of nearby lymph nodes (N), and whether it has metastasized (M). In describing the main tumor, the T describes the size and extent of the primary tumor. The N refers to the
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