question: For patients that have metastatic cancer, how do oncologists determine what organ the cancer started in?
comment: Different cancers have different cells. For instance, testicular cancer can spread to various places including lungs, but it's still testicular cancer and can be treated as such. It's the cells where the mutation occurs that determine what it is. Blood carries it from there and tumors form elsewhere, sometimes in predictable places. Again, I had testicular cancer detected by a blood test, but there were tumors in my stomach that spread there via blood. L Armstrong had his spread to lungs and brain as well but it was testicular.
passages: Most cancers are initially recognized either because of the appearance of signs or symptoms or through screening. Neither of these leads to a definitive diagnosis, which requires the examination of a tissue sample by a pathologist. People with suspected cancer are investigated with medical tests. These commonly include blood tests, X-rays, (contrast) CT scans and endoscopy.
  
  The tissue diagnosis from the biopsy indicates the type of cell that is proliferating, its histological grade, genetic abnormalities and other features. Together, this information is useful to evaluate the prognosis and to choose the best treatment.
   If a tumor is found, a neurosurgeon must perform a biopsy on it. This simply involves the removal of a small amount of tumor tissue, which is then sent to a neuropathologist for examination and grading. The biopsy may take place before surgical removal of the tumor or the sample may be taken during surgery. Grading of the tumor sample is a method of classification that helps the doctor to determine the severity of the astrocytoma and to decide on the best treatment options. The neuropathologist grades the tumor by looking for atypical cells, the growth of new blood vessels, and for indicators of cell division called mitotic figures.
   There are several components of NSCLC staging which then influence physicians' treatment strategies. The lung tumor itself is typically assessed both radiographically for overall size as well as by a pathologist under the microscope to identify specific genetic markers or to see if there has been invasion into important structures within the chest (e.g., bronchus or pleural cavity). Next, the patient's nearby lymph nodes within the chest cavity known as the mediastinum will be checked for disease involvement. Finally, the patient will be evaluated for more distant sites of metastatic disease, most typically with brain imaging and or scans of the bones.
   The histological slides are examined under a microscope by a pathologist, a medically qualified specialist who has completed a recognised training program. This medical diagnosis is formulated as a pathology report describing the histological findings and the opinion of the pathologist. In the case of cancer, this represents the tissue diagnosis required for most treatment protocols. In the removal of cancer, the pathologist will indicate whether the surgical margin is cleared, or is involved (residual cancer is left behind). This is done using either the bread loafing or CCPDMA method of processing.
  
  Section::::In myocardial infarction.
   For instance, breast cancer cells look the same whether they are found in the breast or have spread to another part of the body. So, if a tissue sample taken from a tumor in the lung contains cells that look like breast cells, the doctor determines that the lung tumor is a secondary tumor. Still, the determination of the primary tumor can often be very difficult, and the pathologist may have to use several adjuvant techniques, such as immunohistochemistry, FISH (fluorescent in situ hybridization), and others. Despite the use of techniques, in some cases the primary tumor remains unidentified.
   Section::::Diagnosis.
  
  In recent years, microscopic and other diagnostic techniques have improved dramatically. However, the tissue of origin can be still determined only about in one in four cases of CUPs with these methods. In some cases, the part of the body where cancer cells are first discovered helps the doctor decide which diagnostic tests will be most helpful. Additional clues which may be helpful in determining the primary site include the pattern of spread, and the cell type, which is based on its appearance under a microscope (histology).
   Presence of metastases is determined by a CT scan of the chest, abdomen and pelvis. Other potential imaging tests such as PET and MRI may be used in certain cases. Staging of the cancer is based on both radiological and pathological findings. As for most other forms of cancer, tumor staging is based on the TNM system which considers how much the initial tumor has spread and the presence of metastases in lymph nodes and more distant organs. The AJCC 8th edition was published in 2018.
   Generally, a biopsy is needed to confirm a diagnosis of malignant mesothelioma. A doctor removes a sample of tissue for examination under a microscope by a pathologist. A biopsy may be done in different ways, depending on where the abnormal area is located. If the cancer is in the chest, the doctor may perform a thoracoscopy. In this procedure, the doctor makes a small cut through the chest wall and puts a thin, lighted tube called a thoracoscope into the chest between two ribs. Thoracoscopy allows the doctor to look inside the chest and obtain tissue samples. Alternatively, the chest surgeon might directly open the chest (thoracotomy). If the cancer is in the abdomen, the doctor may perform a laparoscopy. To obtain tissue for examination, the doctor makes a small incision in the abdomen and inserts a special instrument into the abdominal cavity. If these procedures do not yield enough tissue, an open surgical procedure may be necessary.
   BULLET::::- Open biopsy
  
  If the MRI or CT scan indicates the tumour can be treated by surgical removal, the neurosurgeon conducts a craniotomy to remove the tumour.
  
  Section::::Diagnosis.:Blood and Urine test.
  
  Blood and urine tests are rarely done to diagnose CNS tumours since radial imaging and biopsy are the prime diagnostic sources. Blood tests such as a full blood count (FBC) measure the number of each cell type such as white blood cells, red blood cells and platelets. Blood chemistry is also used to check the health of the liver, kidneys and other organs.
  
  Section::::Types.
   Preoperative evaluation involves imaging of the liver and its metastases, for example with ultrasound, computed tomography or magnetic resonance imaging. Positron emission tomography can be useful to check the entire body for metastases, although the test can be falsely normal with small lesions or preoperative chemotherapy. Baseline blood tests typically include liver function tests and tumour markers. During surgery, intraoperative ultrasound can aid the surgeon to find additional metastases.
   If investigations confirm NSCLC, the stage is assessed to determine whether the disease is localized and amenable to surgery or if it has spread to the point where it cannot be cured surgically. CT scan and positron emission tomography are used for this determination. If mediastinal lymph node involvement is suspected, the nodes may be sampled to assist staging. Techniques used for this include transthoracic needle aspiration, transbronchial needle aspiration (with or without endobronchial ultrasound), endoscopic ultrasound with needle aspiration, mediastinoscopy, and thoracoscopy. Blood tests and pulmonary function testing are used to assess whether a person is well enough for surgery. If pulmonary function tests reveal poor respiratory reserve, surgery may not be possible.
   BULLET::::- Laboratory tests are studies of blood, urine, other fluids and tissues removed from the body. These tests can also provide information about the cancer.
  
  BULLET::::- Pathology reports may include information about the size of the tumor, the growth into other tissues and organs, the type of cancer cells, and the grade of tumor (how closely the cancer cells resemble normal tissue). Removing tumors or pieces of tumors and looking at them under the microscope often confirms the diagnosis of cancer, and can also stage the cancer.
   If the site of origin is unknown or undiscovered, then the histology of the tumor (e.g., adenocarcinoma, squamous cell or mesenchymal) can usually be identified, and a probable origin may be assumed. When this is possible, then treatment is based on the type of cell and probable origin. Based on histological subtype, combination chemotherapy may be selected. A combination of carboplatin and paclitaxel is often used. Advances techniques such as FISH and tissue of origin testing may also be employed. Germ cell tumors often carry abnormality of chromosome 12, which if identified, directs treatment for metastatic germ cell tumors.
   In cases where a metastasis from colorectal cancer is suspected, immunohistochemistry is used to ascertain correct diagnosis. Some proteins are more specifically expressed in colorectal cancer and can be used as diagnostic markers such as CK20 and MUC2. Immunohistochemistry can also be used to screen for Lynch syndrome, a genetic disorder with increased risk of colorectal and other cancers. The diagnosis of Lynch syndrome is made by looking for specific genetic mutations in genes MLH1, MSH2, MSH6, and PMS2. Immunohistochemical testing can also be used to guide treatment and assist in determining the prognosis. Certain markers isolated from the tumor can indicate specific cancer types or susceptibility to different treatments.
   The most common way to test someone for PPB is to take a biopsy. Other tests like x-rays, CAT scans, and MRI's can suggest that cancer is present, but only an examination of a piece of the tumor can make a definite diagnosis.
  
  Section::::Diagnosis.:Types.
  
  Pleuropulmonary blastoma is classified into 3 types:
  
  BULLET::::- Type I is multicystic
  
  BULLET::::- Type II shows thickening areas (nodules) within this cystic lesion
  
  BULLET::::- Type III shows solid masses.
   BULLET::::- Physical exams provide clues as to the extent of the cancer. The physical exam may determine the location and size of the tumor(s) and the spread of the cancer to the lymph nodes and/or to other organs.
  
  BULLET::::- Imaging tests such as x-rays, CT scans, and MRI scans produce pictures of areas inside the body and can show the location of the cancer, the size of the tumor, and whether the cancer has spread. These studies are important in determining stage.
   Once Wilms’ tumor is suspected, an ultrasound scan is usually done first to confirm the presence of an intrarenal mass. A computed tomography scan or MRI scan can also be used for more detailed imaging. Finally, the diagnosis of Wilms’ tumor is confirmed by a tissue sample. In most cases, a biopsy is not done first because there is a risk of cancer cells spreading during the procedure. Treatment in North America is nephrectomy or in Europe chemotherapy followed by nephrectomy. A definitive diagnosis is obtained by pathological examination of the nephrectomy specimen.
  
  Section::::Diagnosis.:Staging.
   This team model is based on European standards of care and medical practice, and it entails collaboration by team members on decisions regarding therapy and all aspects of surgical treatment. When these multidisciplinary teams were put into place in Europe, they saw improved outcomes for patients as well as a decrease in recurrence rates and an increase in overall survival rates.
   Typically, new patients meet with either a geriatric oncologist (or sometimes a medical oncologist and geriatrician separately), a psychosocial professional, and a nutritionist, all of whom work together to provide a comprehensive geriatric assessment of the patient's fitness to withstand the therapy necessary to treat his or her cancer. A number of validated screening tools are recommended have been identified to aid this process. Following the initial assessment, the team meets to evaluate the patient's fitness for therapy. The team's decisions and recommendations are then presented to the patient and his or her family as well as to the patient's primary physician when appropriate. After these discussions, and ideally with shared decision-making, treatment for the patient's cancer is decided on and initiated.
   Diagnosis is most commonly made by lumbar puncture although the tests may be negative in roughly 10% of patients. Diagnosis often requires a high index of suspicion and is confirmed by neuroimaging and cerebrospinal fluid analysis. Physicians at Florida Hospital Cancer Institute may recommend a variety of tests and scans to help diagnoses which includes; a physical exam and medical history, a neurological exam and an MRI scan.
  
  Section::::Treatment.
   Colorectal cancer diagnosis is performed by sampling of areas of the colon suspicious for possible tumor development, typically during colonoscopy or sigmoidoscopy, depending on the location of the lesion. It is confirmed by microscopical examination of a tissue sample.
   A biopsy is the most important procedure in diagnosing CNS tumours. When image testing such as MRI and CT scan fail to determine the type of tumour, the alternative is to do a biopsy where tissues are removed from the tumour and tested.
  
  Section::::Diagnosis.:Stereotactic biopsy.
   BULLET::::- 1 point: 0-9 mitotic counts per 10 fields under X25 objective using the Leitz Ortholux microscope, 0-5 mitotic counts per 10 fields under X40 objective using the Nikon Labophot microscope, or 0-11 mitotic counts per 10 fields under X40 objective using the Leitz Daiplan microscope
  
  BULLET::::- 2 points: 10-19 mitotic counts per 10 fields under X25 objective using the Leitz Ortholux microscope, 6-10 mitotic counts per 10 fields under X40 objective using the Nikon Labophot microscope, or 12-22 mitotic counts per 10 fields under X40 objective using the Leitz Daiplan microscope
   SNP array karyotyping can be used to distinguish, for example, a medulloblastoma with an isochromosome 17q from a primary rhabdoid tumor with loss of 22q11.2. When indicated, molecular analysis of INI1 using MLPA and direct sequencing may then be employed. Once the tumor-associated changes are found, an analysis of germline DNA from the patient and the parents can be done to rule out an inherited or de novo germline mutation or deletion of INI1, so that appropriate recurrence risk assessments can be made.
  
  Section::::Examples of clinical cancer applications.:Uveal melanoma.
   Section::::National Program of Cancer Registries (NPCR).
  
  The program has state-based cancer registries that collect, analyze and report cancer cases and deaths to a central cancer registry. NPCR was established in 1992 and administered by the CDC. NPCR supports central cancer registries in 45 states, District of Columbia, Puerto Rico, and the U.S. Pacific Island Jurisdictions (covers approximately 96% of the U.S. population). State Cancer Registries monitor cancer trends, determine cancer patterns, direct planning and evaluation of cancer control programs, help set priorities for allocating health resources, promote research, and provide information on cancer incidence.
  