c l i n i c a l
f o l i o s :
d i s c u s s i o n
Lung Cancer
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Lung Cancer | ||
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Related narrative: Right Upper Lobectomy Lung cancer is the most common cause of cancer mortality in the United States and worldwide. The American Cancer Society estimates that there will be 154,900 lung cancer deaths in the United States in 2002. This is significantly higher when compared with 127,000 deaths from colorectal, prostate and breast cancers combined. The most significant risk factor for the development of lung cancer is cigarette smoking. Other environmental exposures that increase the risk of lung cancer include chromium, nickel, vinyl chloride, asbestos, arsenic, and radon. Lung cancer is broadly divided into two groups based on histology: (1) Small Cell Lung Cancer (SCLC) and (2) Non-small Cell Lung Cancer (NSCLC). Approximately 80% of lung cancers are NSCLC. These NSCLC are further subdivided into 3 groups, which include (1) adenocarcinoma (40%), (2) squamous cell carcinoma (30%), (3) large cell carcinoma (10%). This histologic differentiation into SCLC and NSCLC is critical when determining treatment modalities. The majority of patients with lung cancer(s) will present with an asymptomatic abnormality on chest X-ray. If symptoms are present, they may vary depending on location and size of the tumor. Symptoms may include cough, bronchorrhea, dyspnea, hemoptysis, chest pain, weight loss, wheezing and/or stridor. Some symptoms result from intrathoracic spread of the cancer and present as pleural/pericardial effusions, a hoarse voice, superior vena cava syndrome, Horner's syndrome, and/or arm/shoulder pain from brachial plexus involvement. Finally, approximately 2% of patients with lung cancer present with a paraneoplastic syndrome including Cushing's syndrome, hypercalcemia, syndrome of inappropriate antidiuretic hormone, carcinoid syndrome, or gynecomastia. The evaluation of a patient with lung cancer is focused on staging the tumor and determining the functional status of the patient. Most cases of SCLC are considered non-surgical (i.e. they are treated with chemotherapy and/or radiation). An initial assessment will determine the extent of local disease and the presence or absence of metastatic disease. The most common sites of metastasis for NSCLC are (1) brain, (2) supraclavicular lymph nodes, (3) contralateral lung, (4) bones, (5) liver, and (6) adrenal glands. After gaining information from a patient's chest X-ray and baseline labs, it is common to perform a CT scan of the chest and upper abdomen. This imaging modality allows for assessment of the primary tumor, the contralateral lung, mediastinal lymphadenopathy, and the adrenal glands. These studies along with a thorough history and physical examination are used to determine if further imaging of the brain and/or bones will be necessary. High-resolution CT scans are helpful in staging mediastinal lymph nodes, however; sensitivity and specificity are approximately 70% and 60% respectively. When a CT scan is combined with mediastinoscopy, the sensitivity and specificity are increased to 90 and 100% respectively. Mediastinoscopy is used to assess paratracheal as well as subcarinal lymph nodes, and is indicated in any tumor presenting with mediastinal lymphadenopathy. Determining functional status is critical in this patient population because they tend to have multiple co-morbidities. Functional testing should include the assessment of cardiac function and pulmonary function (PFTs). PFTs are essential in determining a patient's ability to tolerate lung resection. Treatment for NSCLC is based on staging. Although decisions regarding treatment options are extremely complex, the following over-simplification may be applied; (1) stage I cancer is treated with surgery alone; (2) stage II cancer is treated with surgery and/or adjuvant chemo/radiation; (3) stage IIIa cancer is often treated with neoadjuvant therapy followed by surgery and; (4) stage IIIb and IV are treated with palliation and systemic chemotherapy. References: General Thoracic Surgery 5th Edition, T. Shields, Lippincott Williams and Wilkins, Philadelphia, PA, 2000. Advanced Therapy in Thoracic Surgery, K. Franco, J. Putman, B.C. Decker Inc., Hamilton, Ontario, 1998. Surgery of the Chest 6th Edition, D. Sabiston, F. Spencer, W.B. Saunder Company, Philadelphia, PA, 1995. Up to Date, www.uptodate.com, Overview of Clinical Manifestations of Lung Cancer, G.M. Strauss.
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