Non-small cell carcinoma

Non-small cell carcinoma is a term used to describe a group of cancers made up of large cells. This term is usually applied to cancers that start in the lungs, however, it is also occasionally used for cancers that start in other parts of the body. Cancers in this group account for approximately 85% of all lung cancer cases and are characterized by a slower growth rate and spread compared to small cell carcinoma. This categorization is crucial for determining the most appropriate treatment approach.

Types of non-small cell carcinoma

Non-small cell carcinoma is further divided into several major types, based on the kind of cells from which the cancer originates and how the cancer cells look when examined under the microscope.

The most common types of non-small cell carcinoma are:

  • Adenocarcinoma: Adenocarcinoma is the most common form of lung cancer, especially among non-smokers. It originates in the cells of the alveoli (the tiny air sacs in the lungs where oxygen is exchanged for carbon dioxide in the blood).
  • Squamous cell carcinoma: Squamous cell carcinoma begins in the squamous cells, which are flat cells lining the inside of the airways in the lungs. It is often linked to a history of smoking and tends to be found in the central part of the lungs.
  • Large cell carcinoma: Large cell carcinoma includes lung cancers that do not fit into other categories, often because the cancer cells are large and appear abnormal under a microscope. Large cell carcinoma can grow and spread quickly, making it more difficult to treat.

How is this diagnosis made?

The diagnosis of non-small cell carcinoma typically involves a combination of clinical assessment, imaging studies, and pathological evaluation:

  • Imaging studies: Chest X-rays, CT scans, PET scans, and MRI scans are used to detect lung abnormalities, assess the size and location of tumors, and check for metastasis (spread of cancer to other parts of the body).
  • Biopsy: A biopsy is essential for confirming the diagnosis of non-small cell carcinoma. Tissue samples can be obtained through various methods, such as bronchoscopy, fine needle aspiration biopsy (FNAB), or surgical biopsy. A pathologist then examines these samples under a microscope to determine the specific type of cancer.
  • Molecular testing: In addition to histological diagnosis, molecular testing of the tumor tissue may be performed to identify specific gene mutations, rearrangements, or protein expressions. This information can help guide targeted therapy and predict response to certain treatments.
  • Staging: Once non-small cell carcinoma is diagnosed, further tests are conducted to determine the stage of the cancer, which is crucial for planning treatment. Staging involves evaluating the size of the tumor, the involvement of lymph nodes, and whether the cancer has spread to distant organs.

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