Lung Cancer Study Notes

Cancer of the Lung

Anatomic Alterations of the Lungs

• Cancer: Abnormal new tissue growth characterized by progressive, uncontrolled multiplication of cells.
• This abnormal growth is called a neoplasm or tumor.
• Tumors can be localized or invasive, benign or malignant.
• Benign Tumors:
  • Do not endanger life unless they interfere with normal organ functions or affect a vital organ.
• Malignant Tumors:
  • Composed of embryonic, primitive, or poorly differentiated cells.
  • Grow rapidly and in a disorganized manner, leading to nutrition problems for the cells.
  • Can cause necrosis, ulceration, and cavity formation.
• Lung Cancer:
  • Arises from the epithelium of the tracheobronchial tree.
  • A tumor originating in the bronchial mucosa is called bronchogenic carcinoma.
• Major Pathologic or Structural Changes:
  • Inflammation, swelling, and destruction of bronchial airways and alveoli.
  • Excessive mucus production.
  • Tracheobronchial mucus accumulation and plugging.
  • Airway obstruction.
  • Atelectasis.
  • Alveolar consolidation.
  • Cavity formation.
  • Pleural effusion.

Etiology and Epidemiology

• Lung cancer is the second most common cancer in both men and women.
• Cigarette Smoking:
  • The most common cause of lung cancer.
  • Smoking cessation is important.
  • Pack-years are calculated as packs per day × years smoked.
    Pack\text{-}years = packs \text{ per day} \times years \text{ smoked}
• Radon Exposure:
  • The second leading cause of lung cancer.

Exposure to Other Cancer-Causing Agents

• Asbestos
• Radioactive ores (e.g., uranium)
• Inhaled chemicals or minerals
• Diesel exhaust
• Air pollution (especially near heavily trafficked roads)
• Arsenic in drinking water
• Radiation therapy to the lungs
• Personal or family history of lung cancer

Types of Cancer

• Bronchogenic carcinomas are divided into two major categories:
  • Non–Small Cell Lung Carcinoma (NSCLC)
    • Squamous (epidermoid) cell carcinoma
    • Adenocarcinoma (including bronchial alveolar cell carcinoma)
    • Large cell carcinoma
  • Small Cell Lung Carcinoma (SCLC)
    • Small cell carcinoma (also called oat cell carcinoma)
    • Combined small cell carcinoma (mixture of small cell and non–small cell carcinoma)

Non–Small Cell Lung Carcinoma (NSCLC)

• The most common type of lung cancer.
• Squamous Cell Carcinoma:
  • Originates from the basal cells of the bronchial epithelium.
  • Grows through the epithelium before invading surrounding tissues.
  • Slow growth rate and late metastatic tendency.
• Adenocarcinoma:
  • Arises from the mucous glands of the tracheobronchial tree.
  • Moderate growth rate and early metastatic tendency.
• Large Cell Carcinoma:
  • Referred to as undifferentiated large cell anaplastic cancer.
  • Commonly arises peripherally but may also be found centrally.
  • Rapid growth rate and early and widespread metastasis.

Small Cell Lung Carcinoma (SCLC)

• Most tumors arise centrally near the hilar region.
• Grows very rapidly, becomes very large, and metastasizes early.
• Has the poorest prognosis.
  • About 90% of patients respond to treatment.
  • Nearly all relapse within 24 months.
• Has the strongest correlation with cigarette smoking.

Other Types of Lung Tumors

• Lung Carcinoid Tumor:
  • A type of cancer that starts in the lungs.
  • Made up of special types of cells called neuroendocrine cells.
  • Four types of neuroendocrine lung tumors:
    • Small cell lung cancer
    • Large cell neuroendocrine carcinoma
    • Typical carcinoids
    • Atypical carcinoids
• Carcinoids:
  • Central carcinoids: Found in the walls of large bronchi near the center of the lungs.
  • Peripheral carcinoids: Found in the smaller bronchioles toward the periphery of lungs.

Cancer that Spreads to the Lungs

• Cancer that begins in other parts of the body can metastasize to the lungs (e.g., breast, pancreas, kidney, skin).
• Treatment is based on where the cancer originated.

Screening and Diagnosis

• Most lung cancers are not diagnosed until the patient presents with symptoms.

• Symptoms:

  • A progressively worsening cough—often includes blood or rust-colored sputum.
  • Chest pain.
  • Hoarse voice.
  • Poor appetite and weight loss.
  • Dyspnea.
  • Fatigue.
  • Frequent bronchial infection or pneumonia episodes.
  • Sudden onset of wheezing.

• When lung cancer spreads to other parts of the body, the patient may have other symptoms of cancer:

  • Bone pain (e.g., back or hips).
  • Neurologic problems (e.g., headache).
  • Arm and leg weakness or numbness.
  • Dizziness or balance problems.
  • Seizures.
  • Jaundice.
  • Enlarged lymph nodes.

• The patient may demonstrate specific syndromes associated with lung cancer:

  • Horner’s syndrome.
  • Superior vena cava syndrome.
  • Paraneoplastic syndromes.

• The primary goal of diagnostic procedures:

  • Confirm the presence of lung carcinoma.
  • Establish the cancer cell type.
  • Confirm the stage of the cancer.

Staging of Non–Small Cell Lung Carcinoma (NSCLC)

• The tumor node metastasis (TNM) staging system:
  • The staging of lung cancer confirms the:
    • Cell type.
    • Size of the tumor.
    • Level of lymph node involvement.
    • Extent to which the cancer has spread.
• The stage of a patient’s cancer is determined by a combination of all of the following factors:
  • T—Represents the size and location of the primary tumor.
  • N—Denotes the regional lymph node involvement.
  • M—Signifies the extent of metastasis (e.g., common sites are the brain, bones, adrenal glands, liver, kidneys, and other lung).
• Letters after the T, N, and M provide more information about each of these factors.
• Numbers 0 through 4 represent increasing severity.

Stage Grouping for Lung Cancer

• Once the T, N, and M categories have been established:
  • Information is grouped together to determine the overall stage of the lung cancer.
• Stages 0, I, II, III, and IV are used to identify the overall stage of the lung cancer:
  • Stage 0 and I being the least advanced.
  • Stage IV the most advanced.

Staging of Small Cell Lung Carcinoma (SCLC)

• For treatment reasons, SCLC is usually classified as a limited stage or an extensive stage:
  • Limited stage—means the cancer is confined to only one lung and to its neighboring lymph nodes.
    • It can be treated with a single radiation field.
    • In some cases, the lymph nodes at the center of the chest (mediastinal lymph nodes) may be included, even when the cancer is close to the other lung.
    • About 1 out of 3 patients with small cell lung cancer have limited stage SCLC.

Overview of the Cardiopulmonary Clinical Manifestations

• The following clinical manifestations result from the pathophysiologic mechanisms caused (or activated) by:
  • Atelectasis
  • Alveolar consolidation
  • Excessive bronchial secretions

The Physical Examination

• Vital signs:
  • Increased:
    • Respiratory rate (tachypnea)
    • Heart rate (pulse)
    • Blood pressure
  • Cyanosis
  • Cough, sputum production, and hemoptysis
  • Chest assessment findings:
    • Crackles and wheezing

Pulmonary Function Test (PFT) Findings

• Depending on where the malignancy originates, the PFT results may show either obstructive or restrictive values.
• When large amounts of pulmonary tissue, chest wall, and/or diaphragm are involved:
  • The pathology may show restrictive PFT values.

Radiologic Findings

• Chest radiograph:
  • Small oval or coin lesion
  • Large irregular mass
  • Alveolar consolidation
  • Atelectasis
  • Pleural effusion
  • Involvement of the mediastinum or diaphragm

General Management of Lung Cancer

• Treatment options for non–small cell lung cancer (NSCLC):
  • Surgery
    • Pneumonectomy, Lobectomy, Segmentectomy or wedge resection, Sleeve resection, VATS
  • Radiofrequency ablation (RFA)
  • Radiation therapy
    • External beam radiation therapy (EBRT)
    • Brachytherapy
  • Chemotherapy
  • Targeted therapies
• Treatment options for small cell lung cancer (SCLC):
  • Chemotherapy
  • Radiation therapy
  • Surgery