Diagnostic Tests
Chest X-Ray – can assist in locating a tumor – most often is the first test. A chest x-ray may not show a tumor if it is hidden behind a rib or a breastbone or is smaller than 3mm. An x-ray can however indicate there is a problem that requires further investigation.
CT and MRI Scans – CT (computerized axial tomography) and MRI (magnetic resonance imaging) scans use computers to produce highly detailed cross sectional (slices) images of the body. They can show three dimensional images that can help determine size, shape and location of a tumor.
PET Scan (positron emission tomography) – a nuclear scan that measures metabolism. Cancer cells grow faster than normal cells and presumably metabolize faster – a difference that can be detected by PET. PET scans, can assist in determining whether abnormalities seen on CT are cancerous.
Sputum Cytology is the examination of a sample of sputum (mucous) under a microscope for signs of cancer. One method is the bronchoscopy in which a flexible tube (a bronchoscope) is inserted through the nose into the lungs.
Biopsy – examination of tissue under a microscope. This is necessary to confirm a cancer diagnosis and to identify the specific type and its stage. A needle biopsy is used to aspirate a sample. A biopsy can also be performed surgically either as a thoracoscopy which is a limited surgical procedure or as a major operation called a thoracotomy
Genetic Markers – in the future, it is predicted blood samples will be able to detect specific genetic markers associated with lung cancer.
Staging of the Disease
The current staging system is being reevaluated. A new system is expected to be in place within the next two years.
At this time, the following guidelines are in place:
Guidelines for NSCLS:
Stage 0 cancer is found only in the lining of the air passages.
Stage I tumors that are small and do not have any lymph node involvement
Stage II tumors that have spread to local lymph nodes or tumors abutting the chest wall without lymph node involvement.
Stage IIIA tumors that are large and bulky but are still surgically resectable(operable) or tumors that have spread to the mediastinal lymph nodes
Stage IIIB tumors that have not yet metastized but are too large to resect or are located in an Inoperable area; also possible pleural effusion
Stage IV tumors that have spread
Guidelines for SCLC – staging is typically divided into limited stage that is confined to one side of the chest or extensive – that is cancer that has spread outside the side of the chest from where it arose.
TNM System – used by physicians to further stage the disease. T stands for tumor and refers to size and how far it has spread within the lungs nearby organs; N stands for node and indicates whether cancer has spread to lymph nodes and how far away the affected lymph nodes are; M stands for metastasis and refers to whether cancer has spread beyond the lungs to other parts of the body.
Early Detection
Most often lung cancer is detected late stage which in part accounts for the current 15-16% five year survival rates. Early detection of the disease through “screening” (as well as prevention) is key to drastically changing those statistics.
Screening programs are designed to identify and follow high risk patients in order to detect the disease at an early and potentially curable stage.
At this time there is no “officially” recommended screening protocol for lung cancer. Studies are being conducted to evaluate the efficacy of spiral ct screening. This scan is a painless procedure that produces three-dimensional, cross-section images. Unlike x-rays, Spiral CTs can detect smaller growths (nodules) _ that may eventually become tumors. Studies have recently been reported in both the New England Journal of Medicine and JAMA. Since 2001, The National Cancer Institute has conducted a large scale lung cancer screening trial whose findings are to be published no later than 2009. Lung Cancer Circle of Hope strongly encourages individuals to discuss their risks with a qualified physician and to evaluate whether a spiral CT scan or any other “test” is appropriate for them.