Definition
A.Lung cancer is the uncontrolled growth of abnormal cells that form in tissues of one or both lungs, usually in the cells lining air passages. These abnormal cells divide rapidly to form tumors.
B.The two main types are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).
1.NSCLC.
a.NSCLC is the most common type of lung cancer, comprising 85% of the lung cancer diagnoses.
b.There are three histologic subtypes of NSCLC arising from different lung cells, which have similar prognosis and treatment.
i.Adenocarcinoma.
1)Most common subtype of NSCLC, making up roughly 40% of lung cancers, and it is the most common type of lung cancer found in nonsmokers.
2)Originates in glandular cells that typically secrete mucus.
ii.Squamous cell carcinoma.
1)Typically linked to a history of smoking.
2)Tumors are often located in the central area of the lungs near the main bronchus.
3)Comprises 25% to 30% of lung cancer diagnoses.
4)Originates in the flat cells that coat the inside of the airways called squamous cells.
iii.Large cell (undifferentiated) carcinoma.
1)Accounts for 10% to 15% of lung cancers.
2)Can occur anywhere in the lung but often appears as a large peripheral mass on chest radiograph.
3)Tends to grow and spread quickly.
4)Due to its tendency for rapid growth and metastasis, it is more difficult to treat.
2.SCLC.
a.SCLC, previously known as oat cell lung cancer, accounts for 15% to 20% of all lung cancers.
b.Associated with a poor prognosis due to the advanced stage (usually metastatic) at the time of diagnosis.
Incidence
A.Lung cancer is the second most common cancer among both women and men, accounting for approximately 14% of all new cancer diagnoses. However, it is the number one cause of cancer deaths among both women and men each year.
B.More individuals die annually from lung cancer than of breast, prostate, and colon cancer combined.
C.Lung cancer primarily occurs in people over the age of 65 with less than 2% being younger than age 45.
D.The average age at diagnosis is 70 years old.
E.The survival rate among individuals with lung cancer varies based on staging at the time of diagnosis. However, if diagnosed and treated early it can be cured.
F.Five-year overall survival rate is ~17.7% for all patients or 55.2% for patients presenting with localized disease (i.e., early detection).
Pathogenesis
A.Lung cancer can be divided into two broad categories: Small cell and non-small cell carcinoma.
1.Small cell carcinoma is almost exclusively caused by exposure to cigarette smoking.
2.Non-small cell carcinoma (adenocarcinoma, squamous cell and large cell carcinoma) can be caused by other environmental factors such as:
a.Smoking.
b.Radon gas.
c.Pollution.
d.Asbestos.
e.Radiation.
f.Toxic dust.
g.Coal.
h.Diesel.
i.Arsenic.
Predisposing Factors
A.History of smoking (cigarette/cigar/pipe/marijuana). This is dose dependent, meaning the increased quantity and duration of smoking increase the risk of lung cancer.
B.Exposure to radon or asbestos.
C.History of lung cancer in the immediate family.
D.Exposure to Agent Orange or other carcinogens.
E.Diagnosis of another respiratory disease such as chronic obstructive pulmonary disease (COPD), emphysema, chronic bronchitis, or pneumonia.
F.Contact with secondhand smoke.
Subjective Data
A.Common complaints/symptoms.
1.Cough, especially if persistent (the most common).
2.Shortness of breath.
3.Hemoptysis.
4.Pain in the chest, back, or shoulder unrelated to cough.
5.Changes in voice or becoming hoarse.
6.Recurrent lung problems, like bronchitis or pneumonia.
7.Wheezing.
8.Bone pain (with bone metastasis).
9.Headaches (with intracranial metastasis).
10.Unexplained weight loss.
11.Fatigue.
B.Common/typical scenario.
1.Patients are frequently asymptomatic with symptoms only developing once the disease is well advanced.
2.Often, lung cancer is discovered incidentally on chest imaging.
Physical Examination
A.Check vital signs including pulse oximetry.
B.Head and neck.
1.Evaluate pupils for symmetry and reaction to light. Tumor in the lung apex can cause compression of the cervical sympathetic plexus, which can cause Horner syndrome (ptosis, miosis, and anhidrosis).
2.Palpate the neck and supraclavicular area for adenopathy.
3.Evaluate the neck for facial edema, facial cyanosis, or jugular vein distention (JVD), which could indicate superior vena cava (SVC) syndrome if the tumor is obstructing the SVC.
C.Pulmonary system.
1.Observe for signs of dyspnea, increased work of breathing, or retractions.
2.Auscultate lung sounds in all lung fields. Lung tumor can lead to obstruction and collapse of a lobe or entire lung or postobstructive pneumonia. Pleural effusions may develop as well. All of these scenarios would lead to decreased breath sounds in those areas of the lung affected.
3.Percussion of the lung will be dull with collapsed lobes of the lung or pleural effusion.
D.Cardiovascular system.
1.Auscultate heart sounds, which should be normal. If the tumor has direct cardiac involvement, or pericardial effusion has developed, the heart sounds may be affected.
2.Assess for signs of cardiac tamponade, such as hypotension, distant/muffled heart sounds, pericardial rub, or JVD.
E.Gastrointestinal tract.
1.Auscultate for bowel sounds in all four quadrants.
2.Palpate for hepatomegaly. One of the most common sites of lung metastasis is the liver, which can manifest as tender hepatomegaly.
F.Musculoskeletal system.
1.Bone is another area of common metastasis.
2.Patients may report bone pain or tender spots on examination, including the spine.
3.Lung cancers that arise in the lung apex, called Pancoast tumors, can cause shoulder or scapula pain that radiates down the arm.
G.Central nervous system.
1.A neurological examination should be performed to evaluate for any focal neurological deficits that may be produced by intracranial metastases or spinal cord compression.
2.Evaluation for neuropathy, decreased sensation, or decreased strength should be performed.
Diagnostic Tests
A.Laboratory data.
1.Complete blood count (CBC).
2.Comprehensive metabolic panel (CMP).
3.Prothrombin time/international normalized ratio (PT/INR) and partial thromboplastin time (PTT).
B.Imaging and procedures.
1.Chest x-ray.
2.CT of the chest with contrast.
3.PET/CT scan to assess for metastatic disease.
4.Endobronchial ultrasound (EBUS) to evaluate mediastinal lymph nodes.
5.Brain MRI to complete staging.
C.Biopsy: Interventional radiology (IR) CT guided biopsy.
D.Ancillary tests prior to surgery.
1.EKG.
2.Pulmonary function test (PFT).
E.Diagnosis: Tissue sample or biopsy is required for diagnosis; these are typically obtained through a CT-guided biopsy of the lung nodule/mass.
1.Staging is one of the most important elements in determining therapeutic options and prognosis. The staging for NSCLC and SCLC differ as noted in the following.
a.NSCLC.
i.Like the majority of cancers, NSCLC is staged by the tumor, node, metastasis (TNM) system.
ii.Higher numbers indicate more advanced lung cancer.
iii.Staging determines the approach to treatment (i.e., surgery, chemotherapy, radiation, or combination of treatment modalities).
b.SCLC: SCLC has a two-stage system: Limited versus extensive stage.
i.Limited stage: Localized to one hemithorax. Lymph nodes may be involved but they too must be located in the ipsilateral hemithorax in relation to the primary tumor.
ii.Extensive stage involves lung cancer in both hemithoraces and/or metastasis to other organs and/or contralateral nodal metastasis. Staging determines the approach to treatment (chemoradiation vs. chemotherapy alone).
Differential Diagnosis
A.Adenocarcinoma.
B.Squamous cell carcinoma.
C.Large cell carcinoma.
D.Small cell carcinoma.
E.Pulmonary nodule.
Evaluation and Management Plan
A.General plan.
1.Based on staging, patients will be offered chemotherapy +/− radiation, stereotactic body radiation therapy (SBRT), and/or surgery.
2.Targeted therapies.
B.Acute care issues in lung cancer.
1.Lung cancer patients are often only admitted for surgical resection.
a.Pneumonectomy: Removal of the entire lung.
b.Lobectomy: The most common surgical procedure in lung cancer patients, with removal of a single lobe of the lung.
c.Segmental resection: Removal of a segment/portion of the involved lobe.
d.Sleeve resection: Consider when the cancer is confined to the bronchus or pulmonary