Lung cancer
Lung cancer: Excerpt from Handbook of Diseases
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 spread at the time of diagnosis and the growth rate of the specific cell type. Only about 13% of patients with lung cancer survive 5 years after diagnosis. Lung cancer is the most common cause of cancer death in men and is fast becoming the most common cause in women, even though it’s largely preventable. It’s associated with more cancer deaths per year than heart, colon, and prostate cancer combined.
Causes
Most experts agree that lung cancer is attributable to inhalation of carcinogenic pollutants by a susceptible host. Most susceptible are those persons who smoke or who work 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; indeed, 80% of lung cancer patients are or were 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 the 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 typically in an advanced state at diagnosis. The following late-stage signs and symptoms commonly lead to a diagnosis:
❑ with epidermoid and small cell carcinomas: smoker’s cough, hoarseness, wheezing, dyspnea, hemoptysis, and chest pain
❑ with adenocarcinoma and large cell carcinoma: fever, weakness, weight loss, anorexia, and shoulder pain.
Besides 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 or 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, and dyspnea
❑ recurrent nerve invasion: hoarseness and vocal cord paralysis
❑ chest wall invasion: piercing chest pain; increasing dyspnea; and severe shoulder pain, radiating down the arm
❑ local lymphatic spread: cough, hemoptysis, stridor, and pleural effusion
❑ phrenic nerve involvement: dyspnea; shoulder pain; and unilateral paralyzed diaphragm, with paradoxical motion
❑ esophageal compression: dysphagia
❑ vena caval obstruction: venous distention and edema of the face, neck, chest, or back
❑ pericardial involvement: pericardial effusion, tamponade, and arrhythmias
❑ cervical thoracic sympathetic nerve involvement: miosis, ptosis, exophthalmos, and reduced sweating.
Distant metastasis may involve any part of the body, most commonly the central nervous system, liver, and bone.
Diagnosis
Typical signs and symptoms may strongly suggest lung cancer, but a firm diagnosis requires further evidence, including the following:
❑ 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 is marginally helpful in obtaining a diagnosis. It 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.
❑ A needle biopsy of the lungs uses biplane fluoroscopic visual control or CT guidance to detect peripherally located tumors. This allows a firm diagnosis in 80% of patients.
❑ Tissue biopsy of accessible metastatic sites includes supraclavicular and mediastinal node and pleural biopsies.
❑ 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 a bone scan, positron emission tomography scan, bone marrow biopsy (recommended in small cell carcinoma), and a CT scan of the brain or abdomen.
After histologic confirmation, staging determines the extent of the disease and helps in planning treatment and predicting the prognosis. (See Staging lung cancer.)
Treatment
Various combinations of surgery, radiation, and chemotherapy may improve the prognosis and prolong survival. Nevertheless, because treatment usually begins at an advanced stage, it’s largely palliative.
Surgery
Unless the tumor is nonresectable or other conditions rule out surgery, excision is the primary treatment for stage I, stage II, or selected stage III squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. Surgery may include partial removal of a lung (wedge resection, segmental resection, lobectomy, radical lobectomy) or total removal (pneumonectomy, radical pneumonectomy).
Radiation
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 1 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.
Chemotherapy
Another treatment is chemotherapy, including combinations of drugs, which produce a response rate of about 40%, but have a minimal effect on overall survival. Promising combinations for treating small cell carcinomas include cyclophosphamide with doxorubicin and vincristine; cyclophosphamide with doxorubicin, vincristine, and etoposide; and etoposide with cisplatin, cyclophosphamide, and doxorubicin.
Laser therapy
Some patients may undergo laser therapy, which involves direction of laser energy 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 information about the disease and the surgical procedure.
❑ Explain expected postoperative procedures, such as the insertion of an indwelling urinary catheter, use of an endotracheal 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.
After thoracic surgery:
❑ Maintain a patent airway, and monitor chest tubes to reestablish normal intrathoracic pressure and prevent postoperative and pulmonary complications.
❑ Check the patient’s vital signs every 15 minutes during the first hour after surgery, every 30 minutes during the next 4 hours, and then every 2 hours. Watch for abnormal respiration and other changes.
❑ Suction the patient often, 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.
CLINICAL TIP: Position the patient on the surgical side to promote drainage and lung reexpansion.
❑ Watch for and report foul-smelling discharge and excessive drainage on the dressing. Usually, the dressing is removed after 24 hours, unless the wound appears infected.
❑ Monitor the patient’s intake and output. Maintain adequate hydration.
❑ Watch for and treat infection, shock, hemorrhage, atelectasis, dyspnea, mediastinal shift, and pulmonary embolus.
❑ To help 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 an antiemetic and an antidiarrheal 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.
Teach high-risk patients ways to reduce their chances of developing lung cancer:
❑ Refer smokers who want to quit to local branches of the American Cancer Society, Smokenders, or other smoking-cessation programs or suggest group therapy, individual counseling, or hypnosis.
❑ Encourage patients with recurring or chronic respiratory tract infections and those with chronic lung disease who detect any change in the character of a cough to see their physician promptly for evaluation.
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Book Source Details
- Book Title: Handbook of Diseases
- Author(s): Springhouse
- Year of Publication: 2003
- Copyright Details: Handbook of Diseases, Copyright © 2003 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Handbook of Diseases
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2003
ISBN: 1-58255-266-5
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