Lung cancer
Lung cancer: Excerpt from Professional Guide to Diseases (Eighth Edition)
Even though it's largely preventable, lung cancer has long been the most common cause of cancer death in men and is an increasing cause of cancer death in women. Lung cancer usually develops within the wall or epithelium of the bronchial tree. Its most common types are epidermoid (squamous cell) carcinoma, small cell (oat cell) carcinoma, adenocarcinoma, and large cell (anaplastic) carcinoma. Although the prognosis is usually poor, it varies with the extent of metastasis at the time of diagnosis and the cell type growth rate. Only about 14% of patients with lung cancer survive 5 years after diagnosis.
Causes and incidence
Most experts agree that lung cancer is attributable to inhalation of carcinogenic pollutants by a susceptible host. Who's most susceptible? Any smoker older than age 40, especially if he began to smoke before age 15, has smoked a whole pack or more per day for 20 years, or works with or near asbestos.
Pollutants in tobacco smoke cause progressive lung cell degeneration. Lung cancer is 10 times more common in smokers than in nonsmokers; 80% of patients with lung cancer are smokers. Cancer risk is determined by the number of cigarettes smoked daily, the depth of inhalation, how early in life smoking began, and the nicotine content of cigarettes. Two other factors also increase susceptibility: exposure to carcinogenic industrial and air pollutants (asbestos, uranium, arsenic, nickel, iron oxides, chromium, radioactive dust, and coal dust) and familial susceptibility.
Signs and symptoms
Because early-stage lung cancer usually produces no symptoms, this disease is usually in an advanced state at diagnosis. These late-stage symptoms commonly lead to diagnosis:
❑Epidermoid and small cell carcinomas — smoker's cough, hoarseness, wheezing, dyspnea, hemoptysis, and chest pain
❑ Adenocarcinoma and large cell carcinoma — fever, weakness, weight loss, anorexia, and shoulder pain.
In addition to their obvious interference with respiratory function, lung tumors may also alter the production of hormones that regulate body function or homeostasis. Clinical conditions that result from such changes are known as hormonal paraneoplastic syndromes:
❑ Gynecomastia may result from large cell carcinoma.
❑ Hypertrophic pulmonary osteoarthropathy (bone and joint pain from cartilage erosion due to abnormal production of growth hormone) may result from large cell carcinoma and adenocarcinoma.
❑ Cushing's and carcinoid syndromes may result from small cell carcinoma.
❑ Hypercalcemia may result from epidermoid tumors.
Metastatic signs and symptoms vary greatly, depending on the effect of tumors on intrathoracic and distant structures:
❑ bronchial obstruction: hemoptysis, atelectasis, pneumonitis, dyspnea
❑ cervical thoracic sympathetic nerve involvement: miosis, ptosis, exophthalmos, reduced sweating
❑ chest wall invasion: piercing chest pain, increasing dyspnea, severe shoulder pain, radiating down arm
❑ esophageal compression: dysphagia
❑ local lymphatic spread: cough, hemoptysis, stridor, pleural effusion
❑ pericardial involvement: pericardial effusion, tamponade, arrhythmias
❑ phrenic nerve involvement: dyspnea, shoulder pain, unilateral paralyzed diaphragm, with paradoxical motion
❑ recurrent nerve invasion: hoarseness, vocal cord paralysis
❑ vena caval obstruction: venous distention and edema of face, neck, chest, and back.
Distant metastasis may involve any part of the body, most commonly the central nervous system, liver, and bone.
Diagnosis
Typical clinical findings may strongly suggest lung cancer, but firm diagnosis requires further evidence.
❑Chest X-ray usually shows an advanced lesion, but it can detect a lesion up to 2 years before symptoms appear. It also indicates tumor size and location.
❑ Sputum cytology, which is 75% reliable, requires a specimen coughed up from the lungs and tracheobronchial tree, not postnasal secretions or saliva.
❑ Computed tomography (CT) scan of the chest may help to delineate the tumor's size and its relationship to surrounding structures.
❑ Bronchoscopy can locate the tumor site. Bronchoscopic washings provide material for cytologic and histologic examination. The flexible fiber-optic bronchoscope increases the test's effectiveness.
❑ Needle biopsy of the lungs uses biplane fluoroscopic visual control to detect peripherally located tumors. This allows firm diagnosis in 80% of patients.
❑ Tissue biopsy of accessible metastatic sites includes supraclavicular and mediastinal node and pleural biopsy. Directed needle biopsy may be performed in conjunction with CT scan.
❑Thoracentesis allows chemical and cytologic examination of pleural fluid.
Additional studies include preoperative mediastinoscopy or mediastinotomy to rule out involvement of mediastinal lymph nodes (which would preclude curative pulmonary resection).
Other tests to detect metastasis include bone scan, bone marrow biopsy (recommended in small cell carcinoma), CT scan of the brain or abdomen, and positron emission tomography.
After histologic confirmation, staging determines the extent of the disease and helps in planning the treatment and predicting the prognosis. (See Staging lung cancer.)
Treatment
Recent treatment, which consists of combinations of surgery, radiation, and chemo-therapy, may improve the prognosis and prolong survival. Nevertheless, because treatment usually begins at an advanced stage, it's largely palliative.
Surgery is the primary treatment for stage I, stage II, or selected stage III squamous cell cancer; adenocarcinoma; and large cell carcinoma, unless the tumor is nonresectable or other conditions rule out surgery.
Surgery may include partial removal of a lung (wedge resection, segmental resection, lobectomy, or radical lobectomy) or total removal (pneumonectomy or radical pneumonectomy).
Preoperative radiation therapy may reduce tumor bulk to allow for surgical resection. Preradiation chemotherapy helps improve response rates. Radiation therapy is ordinarily recommended for stage I and stage II lesions, if surgery is contraindicated, and for stage III lesions when the disease is confined to the involved hemithorax and the ipsilateral supraclavicular lymph nodes.
Generally, radiation therapy is delayed until one month after surgery, to allow the wound to heal, and is then directed to the part of the chest most likely to develop metastasis. High-dose radiation therapy or radiation implants may also be used.
Research has shown that chemotherapy combinations of paclitaxel, gemcitabine, docetaxel, irinotecan, and vinorelbine are more active and better tolerated when combined with cisplatin or carboplatin. Many of these drugs are also being utilized as single agents for the treatment of small-cell and non–small-cell lung cancers.
In laser therapy, laser energy is directed through a bronchoscope to destroy local tumors.
Special considerations
Comprehensive supportive care and patient teaching can minimize complications and speed recovery from surgery, radiation, and chemotherapy.
Before surgery:
❑Supplement and reinforce the information given to the patient by the health care team about the disease and the surgical procedure.
❑Explain expected postoperative procedures, such as insertion of an indwelling catheter, use of an endotracheal tube or chest tube (or both), dressing changes, and I.V. therapy.
❑Teach the patient how to perform coughing, deep diaphragmatic breathing, and range-of-motion (ROM) exercises.
❑Reassure the patient that analgesics will be provided and proper positioning will be implemented to control postoperative pain.
❑Inform the patient that he may take nothing by mouth beginning after midnight the night before surgery, that he'll shower with a soaplike antibacterial agent the night or morning before surgery, and that he'll be given preoperative medications, such as a sedative and an anticholinergic to dry secretions.
After thoracic surgery:
❑Maintain a patent airway, and monitor chest tubes to reestablish normal intrathoracic pressure and prevent postoperative and pulmonary complications.
❑Check vital signs every 15 minutes during the 1st hour after surgery, every 30 minutes during the next 4 hours, and then every 2 hours. Watch for and report abnormal respiration and other changes.
❑Suction the patient as needed, and encourage him to begin deep breathing and coughing as soon as possible. Check secretions often. Initially, sputum will be thick and dark with blood, but it should become thinner and grayish yellow within a day.
❑Monitor and record closed chest drainage. Keep chest tubes patent and draining effectively. Fluctuation in the water-seal chamber on inspiration and expiration indicates that the chest tube is patent. Watch for air leaks, and report them immediately. Position the patient on the surgical side to promote drainage and lung reexpansion.
❑Watch for and report foul-smelling discharge and excessive drainage on dressing. Usually, the dressing is removed after 24 hours, unless the wound appears infected.
❑Monitor intake and output. Maintain adequate hydration.
❑Watch for and treat infection, shock, hemorrhage, atelectasis, dyspnea, mediastinal shift, and pulmonary embolus.
❑To prevent pulmonary embolus, apply antiembolism stockings and encourage ROM exercises.
If the patient is receiving chemotherapy and radiation:
❑Explain possible adverse effects of radiation and chemotherapy. Watch for, treat and, when possible, try to prevent them.
❑Ask the dietary department to provide soft, nonirritating foods that are high in protein, and encourage the patient to eat high-calorie between-meal snacks.
❑Give antiemetics and antidiarrheals, as needed.
❑Schedule patient care activities in a way that helps the patient conserve his energy.
❑During radiation therapy, administer skin care to minimize skin breakdown. If the patient receives radiation therapy in an outpatient setting, warn him to avoid tight clothing, exposure to the sun, and harsh ointments on his chest. Teach him exercises to help prevent shoulder stiffness.
Educate high-risk patients in ways to reduce their chances of developing lung cancer:
❑Present the benefits of quitting to smokers and encourage them to consider this lifestyle change.
❑Refer smokers who want to quit to local branches of the American Cancer Society or smoking-cession programs or suggest group therapy, individual counseling, or support the patient's use of smoking-cessation products.
❑Encourage patients with recurring or chronic respiratory infections and those with chronic lung disease who detect any change in the character of a cough to see their physician promptly for evaluation.
Pictures
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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