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