Thoracic Surgery Health Article

Definition

Thoracic surgery is any surgery performed in the chest (thorax).

Purpose

The purpose of thoracic surgery is to treat diseased or injured organs in the thorax, including the esophagus (muscular tube that passes food to the stomach), trachea (windpipe that branches to form the right bronchus and the left bronchus), pleura (membranes that cover and protect the lung), mediastinum (area separating the left and right lungs), chest wall, diaphragm, heart, and lungs.

General thoracic surgery is a field that specializes in diseases of the lungs and esophagus. The field also encompasses accidents and injuries to the chest, esophageal disorders (esophageal cancer or esophagitis), lung cancer, lung transplantation, and surgery for emphysema.

Description

The most common diseases requiring thoracic surgery include lung cancer, chest trauma, esophageal cancer, emphysema, and lung transplantation.

Lung cancer

Lung cancer is one of the most significant public health problems in the United States and the world. Approximately 171,600 new cases of lung cancer occurred in 1999. It accounts for 28% of cancer deaths, 14% of all cancer diagnoses, and is the leading cause of cancer deaths among women and second most common cause of male cancer deaths. The five-year survival rate in localized disease can approach 50% (stages I and II).

Lung cancer develops primarily by exposure to toxic chemicals. Cigarette smoking is the most important risk factor responsible for the disease. Other environmental factors that may predispose a person to lung cancer include such industrial substances as arsenic, nickel, chromium, asbestos, radon, organic chemicals, air pollution, and radiation.

Most cases of lung cancer develop in the right lung because it contains the majority (55%) of lung tissue. Additionally, lung cancer occurs more frequently in the upper lobes of the lung than in the lower lobes. The tumor receives blood from the bronchial artery (a major artery in the pulmonary system).

Adenocarcinoma of the lung is the most frequent type of lung cancer, accounting for 45% of all cases. This type of cancer can spread (metastasize) earlier than another type of lung cancer called squamous cell carcinoma (which occurs in approximately 30% of lung cancer patients). Approximately 66% of squamous cell carcinoma cases are centrally located. They expand against the bronchus, causing compression. Small-cell carcinoma accounts for 20% of all lung cancers; and the majority (80%) are centrally located. Small-cell carcinoma is a highly aggressive lung cancer, with early metastasis to such distant sites as the brain and bone marrow (the central portion of certain bones, which produce formed elements that are part of blood).

Most lung tumors are not treated with thoracic surgery since patients seek medical care later in the disease process. Chemotherapy increases the rate of survival in patients with limited (not advanced) disease. Surgery may be useful for staging or diagnosis. Pulmonary resection (removal of the tumor and neighboring lymph nodes) can be curative if the tumor is less than or equal to 3 cm, and presents as a solitary nodule. Lung tumors spread to other areas through neighboring lymphatic channels. Even if thoracic surgery is performed, postoperative chemotherapy may also be indicated to provide comprehensive treatment (i.e., to kill any tumor cells that may have spread via the lymphatic system).

Genetic engineering has provided insights related to the growth of tumors. A genetic mutation called a k-ras mutation frequently occurs, and is implicated in 90% of genetic mutations for adenocarcinoma of the lung. Mutations in the cancer cells make them resistant to chemotherapy, necessitating the use of multiple chemotherapeutic agents.

Chest trauma

Chest trauma is a medical/surgical emergency. Initially, the chest should be examined after an airway is maintained. The mortality (death) rate for trauma patients with respiratory distress is approximately 50%. This figure rises to 75% if symptoms include both respiratory distress and shock. Patients with respiratory distress require endotracheal intubation (passing a plastic tube from the mouth to the windpipe) and mechanically assisted ventilator support. Invasive thoracic procedures are necessary in emergency situations.

Trauma requiring urgent thoracic surgery may include any of the following problems: a large clotted hemothorax, massive air leak, esophageal injury, valvular cardiac (heart) injury, proven damage to blood vessels in the heart, or chest wall defect.