Lung Cancer - Oncology - Medbullets Step 1

Snapshot

A 69-year-old male with a 50 pack-year smoking history presents to his physician with complaint of worsening cough. He describes frequently coughing up blood in the past few weeks. He has unintentionally lost about 10 pounds of weight in the past month and has felt more fatigued than usual. On physical examination, he has ptosis and a constricted pupil in his left eye. His right eye is normal. A chest radiograph is obtained and is shown in the image.

Introduction

Overview lung cancer is a malignancy that affects the lung parenchyma or airways
- most lung cancers can be divided into
  - small cell lung cancer
  - non-small cell lung cancer
Epidemiology
- incidence
  - second most common cancer
  - leading cause of cancer-related death
- risk factors
  - cigarette smoking
    - most important risk factor
    - second-hand smoke exposure is also a risk factor
  - asbestos
  - radon
  - family history of lung cancer
Prognosis
- depends on cancer type and severity
Screening
- performed with a low-dose computerized tomography (CT) scan of the chest
  - indicated in patients 55-80 years of age who have a 30 pack-year smoking history and either of the following
    - currently smoke
    - has quit smoking within the past 15 years

Classification

Small Cell Lung Cancer (SCLC)
Type	Location	Associated Findings	Histology
Small cell (oat cell) lung cancer	Central	MYC gene amplication May produce adrenocorticotropic hormone (ACTH) leads to Cushing syndrome excessive anti-diuretic hormone (ADH) leads to syndrome of inappropriate ADH (SIADH) presynaptic calcium channel antibodies leads to Lambert Eaton syndrome	Small dark blue tumor cells with lack of nucleoli and high nuclear:cytoplasm ratio Positive staining for neuron-specific enolase chromogranin A

Non-Small Cell Lung Cancer (NSCLC)
Type	Location	Associated Findings	Histology
Adenocarcinoma	Peripheral	Most common cause of lung cancer in non-smokers cause of lung cancer (excluding metastasis) Adenocarcinoma in situ tumor growth along alveolar structures lepidic growth pattern Patients may have hypertrophic osteoarthropathy Common gene mutations include KRAS EGFR ALK	Typically mucin positive and has a glandular appearance
Large cell carcinoma	Peripheral	Associated with a poor prognosis Highly associated with smoking	Pleomorphic giant cells
Squamous cell carcinoma of the lung	Central	Can arise from the bronchus	Keratin pearls Intracellular bridges
Bronchial carcinoid tumor	Central or peripheral	Carcinoid syndrome Better prognosis	Neuroendocrine cells Chromogranin A positive

Presentation

Imaging

Radiography
- indication
  - initial imaging modality when evaluating a patient with symptoms concerning for lung cancer
    - very important to review previous chest imaging to assess for lesion properties and changes
Computerized tomography (CT) scan
- indication
  - perform with low-doses to screen for lung cancer (review "screening" in the introduction)
  - further evaluate pulmonary nodule found on radiography
    - chest CT should be obtained for all patients with an unclearly characterized solitary pulmonary nodule seen on radiography

Studies

Differential

Tuberculosis
- differentiating factors
  - abnormal quantiferon or purified protein derivative (PPD) test
  - history of ↑ risk of exposure (e.g., household contact with someone with diagnosed tuberculosis or travel to tuberculosis-endemic area)

Treatment

Small cell lung cancer
- most cases are non-resectable and thus require chemotherapy (e.g., carboplatin and etoposide)
Non-small cell lung cancer
- treatment includes surgical removal, lymph node sampling or dissection, radiation, and chemotherapy
  - depends on the staging

Complications