New Procedure for Diagnosing Lung Cancer
April 12, 2010
Susan Garwood, MD, pulmonologist
Stacey Vallejo, MD, pulmonologist
SAINT THOMAS HOSPITAL
Lung Cancer Symptoms
One fourth of all people with lung cancer have no symptoms when the cancer is diagnosed. These cancers are usually identified incidentally when a chest x-ray is performed for another reason. The other three fourths of people develop some symptoms. The symptoms are due to direct effects of the primary tumor; to effects of metastatic tumors in other parts of the body; or to malignant disturbances of hormones, blood, or other systems.
Symptoms of primary lung cancers include cough, coughing up blood, chest pain, and shortness of breath.
Symptoms of metastatic skin rashes depend on the location and size. About 30-40% of people with lung cancer have some symptoms or signs of metastatic disease.
Types of Lung Cancer
What are the types of lung cancer?
Lung cancers, also known as bronchogenic carcinomas ("carcinoma" is another term for cancer), are broadly classified into two types: small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC). This classification is based upon the microscopic appearance of the tumor cells themselves. These two types of cancers grow and spread in different ways, so a distinction between these two types is important.
SCLC comprise about 20% of lung cancers and are the most aggressive and rapidly growing of all lung cancers. SCLC are strongly related to cigarette smoking with only 1% of these tumors occurring in non-smokers. SCLC metastasize rapidly to many sites within the body and are most often discovered after they have spread extensively. Referring to a specific cell type often seen in SCLC, these cancers are sometimes called oat cell carcinomas.
NSCLC are the most common lung cancers, accounting for about 80% of all lung cancers. NSCLC has three main types that are named based upon the type of cells found in the tumor. They are:
Other types of cancers can arise in the lung; these types are much less common than NSCLC and SCLC and together comprise only 5-10% of lung cancers:
As discussed previously, metastastatic cancers from other primary tumors in the body are often found in the lung. Tumors from anywhere in the body may spread to the lungs either through the bloodstream, through the lymphatic system, or directly from nearby organs. Metastatic tumors are most often multiple, scattered throughout the lung and concentrated in the peripheral rather than central areas of the organ.
NEW MINIMALLY INVASIVE PROCEDURE for Diagnosing and Staging Lung Cancer
The Endobronchial Ultrasound, or EBUS, is advanced technology offering a more precise way of assessing a patient's lymph nodes and determining if lung cancer has spread to other parts of the body. Saint Thomas Hospital is one of the FIRST to have this advanced technology for diagnosing lung cancer and other diseases involving the lymph nodes.
This new technology is changing the practice of cancer staging.
Less Invasive, Shorter Hospital Stay
With lung and esophageal cancers, treatment decisions and the patient's prognosis is directly related to the extent of the disease, or the "stage" of the cancer. Malignancies in the chest can easily spread through the body via lymph nodes. If tumors have invaded a patient's lymph nodes, this can dramatically change the initial "staging" of the cancer, as well as the options for initial treatment.
Lung cancer is typically diagnosed after it has already spread, and long-term prognosis for patients is usually poor. But with the innovation of endobronchial ultrasound and its ability to accurately show the cancer stage, patients with early-stage lung cancer may avoid more extensive surgery. With less-invasive procedures, such patients may then leave the hospital sooner and use less pain medication as they recover.
The type of treatment recommended for lung cancer patients depends to a large degree on the stage of their cancer. The great advantage of this technology is that people who will benefit from surgery will not be denied surgery or receive unnecessary chemotherapy because of less accurate conventional staging with CT and PET scans.
It also means people with advanced lung cancer will not need to undergo unnecessary surgery that may not help them..
The EBUS Procedure
The EBUS technology is a hybrid employing ultrasound guidance with a bronchoscope, enabling real-time transbronchial needle aspiration to be performed. This combination aids in the diagnosis and staging of lung cancer. In clinical trials, many patients evaluated with EBUS were able to forego more invasive procedures, such as mediastinoscopy, thoracoscopy or thoracotomy.
Using EBUS, biopsies are performed through the trachea using ultrasound rather than surgical incisions that must be made in other, more invasive procedures. The EBUS procedure is usually completed in less than half an hour.
In an endobronchial ultrasound, patients are placed under conscious sedation or general anesthesia and a small scope is passed through the mouth down into the windpipe. The scope has a small instrument at its tip called a transducer, which can be pointed in different directions to produce images of lymph nodes and other structures in the area between the lungs, called the mediastinum. The technology allows you to look in areas that have traditionally been hard to biopsy. If suspicious areas are seen–such as enlarged lymph nodes–a hollow needle can be passed through the bronchoscope and guided by real-time ultrasound into the abnormal structures to obtain a biopsy.
Endobronchial Ultrasound is a well-designed system. In many cases, it offers better sensitivity and specificity without having to make an incision.