Diagnosis of Lung Cancer
Detecting Lung Cancer
There are several methods for detecting lung cancer such as:
- Sputum cytology
- Chest X-ray
- Spiral CT Scan
As the cancer grows, following symptoms are commonly observed
- Cough that gets worse
- Constant chest Pain
- Coughing up blood or bloody mucus.
- Shortness of breath.
- Weight loss and loss of appetite.
- Recurring Respiratory Infections
- Hoarse voice
- Feeling of tiredness all the time
Diagnosing Lung Cancer
A wide range of diagnostic procedures and tests are used to diagnose lung cancer. These include:
- The history and physical examination – This may reveal the presence of symptoms or signs that are suspicious for lung cancer. In addition to asking about symptoms and risk factors for cancer development such as smoking, doctors may detect signs of breathing difficulties, airway obstruction, or infections in the lungs. Doctor may also feel for swollen lymph nodes and a swollen liver
- Chest X-ray – The chest X-ray procedure may reveal suspicious areas in the lungs.
- CT (computerized tomography, computerized axial tomography, or CAT) scans – CT scan may be performed on the chest, abdomen or brain to examine for both metastatic and lung tumors. A CT scan of the chest may be ordered when X-rays do not show an abnormality or do not yield sufficient information about the extent or location of a tumor. CT scans are X-ray procedures that combine multiple images with the aid of a computer to generate cross-sectional views of the body.
In addition, one or more of the following tests may be done to find lung cancer cells:
- Sputum cytology – The simplest method to establish the diagnosis is the examination of sputum under a microscope. If a tumor is centrally located and has invaded the airways, this procedure may allow visualization of tumor cells for diagnosis.
- Thoracentesis – Lung cancers involve the lining tissue of the lungs, pleura and lead to an accumulation of fluid in the space between the lungs and chest wall, called pleural effusion. Aspiration of a sample of this fluid with a thin needle is called thoracentesis.
- Bronchoscopy – Bronchoscopy is the procedure of visualizing the airways through a thin, fiberoptic probe inserted through the nose or mouth. It may reveal areas of tumor that can be sampled for diagnosis by a pathologist.
- Fine needle aspiration – In this procedure, a thin needle is used to remove tissue or fluid from the lung or lymph node. Most commonly performed with radiological imaging for guidance, it is useful in retrieving cells for diagnosis from tumor nodules in the lungs.
- Thoracoscopy – Thoracoscopy is the insertion of an endoscope, a narrow diameter tube with a viewing mirror or camera attachment, through a very small incision in the chest wall. If an abnormal area is seen, a biopsy to check for cancer cells may be needed.
- Thoracotomy – Thoracotomy is the surgery to remove part of a lung by making a long incision on one side of the chest. It may be used to confirm the diagnosis of lung cancer. Lymph nodes and other tissue may also be removed.
- Mediastinoscopy – Mediastinoscopy is a surgical procedure to examine the inside of the upper chest between and in front of the lungs (mediastinum). A tissue sample (biopsy) can be collected through the mediastinoscope and then examined under a microscope.
Types of lung cancer
There are two main types of lung carcinoma, categorized by the size and appearance of the malignant cells:
- Non-small cell lung carcinoma (NSCLC): Includes three subtypes
- Squamous cell lung carcinoma (composed of anaplastic small cells)
- Large cell lung carcinoma (composed of large-sized cells that are anaplastic in nature and often arise in the bronchi)
- Adenocarcinoma (cancer of the glandular tissue)
- Small cell lung carcinoma (SCLC also called as oat cell carcinoma): Lung Cancer composed of anaplastic small cells; Small cell lung cancers are divided into limited stage (confined to one half of the chest) and extensive stage disease.
Clinical Staging of Lung Cancer
Following completion of a diagnostic workup, clinical Staging for lung cancer is determined which describes the extent of disease. It is based on a pathology report from tissue obtained during bronchoscopy, needle (or other) biopsy, blood tests, and imaging studies to rule out distant metastasis. Staging may involve blood tests and other tests such as–
Staging of Small Cell Lung Cancer
Small cell lung cancers are staged as either limited stage or extensive stage.
Limited stage small cell lung cancers are loosely defined as those that are contained to a small area. This usually means that the cancer is contained in one lung, and may include involvement of the area between the lungs and adjacent lymph nodes.
Extensive stage means that the tumor is either metastasized to other sites, or is too widespread to be considered limited.
Staging of Non-small Cell Lung Cancer
Stages of non-small cell lung cancer are described on the basis of tumor size, lymph node involvement and metastatic condition. These are the different stages of non-small cell lung cancer—
Occult stage— At this stage tumor is not seen in the lung but the cancer cells are found in the sputum or bronchoscopic examination.
Stage 0—Stage 0 or carcinoma in situ is not an invasive condition. The cancer cells are found only in the innermost lining of the lung.
Stage 1 – The cancer is localized within the lung and has not spread to any lymph nodes. Stage 1 is divided into stage 1A (tumors 3 cm or less in size), and stage 1B (tumors greater than 3 cm).
Stage 2 – The cancer has spread to nearby lymph nodes, or has not spread to lymph nodes but is large, in a certain region of the main bronchus, or in a location where it invades the lung lining. Stage 2 is divided into stage 2A (a tumor 5 cm or less in size with spread to lymph nodes), or stage 2B (tumors 5 cm or greater in size with spread to lymph nodes, or present in locations such as a region of the main bronchus or invading the lung lining or chest wall).
Stage 3A and Stage 3B – The cancer has spread to tissue near the lungs. Stage 3 is divided in stage 3A (large tumors with spread to nearby lymph nodes, or any size tumor that has spread to lymph nodes further away from the tumor), and stage 3B (any size tumor that has spread to distant lymph nodes, a tumor that has invaded other structures in the chest such as the heart or esophagus.
Stage 4 – The cancer has spread to another part of the body. Tumor with malignant pleural effusion in the past had been under the category of stage IIIB, but in the new staging system is stage 4.
Read more: Treatment of Lung Cancer