What are the symptoms of small cell lung cancer?

Symptoms of Small Cell Lung Cancer

Small cell lung cancer (SCLC) typically presents with symptoms related to a large hilar mass and bulky mediastinal lymphadenopathy, causing cough and dyspnea, along with frequent symptoms of widespread metastatic disease such as weight loss, debility, bone pain, and neurologic compromise. 1

Symptoms Due to Local Primary Tumor Growth

• Cough (present in approximately 77% of patients) 1, 2
• Dyspnea/shortness of breath (34-45% of patients) 1, 3, 2
• Hemoptysis (10% of patients) 1, 3
• Wheezing (from partially obstructing endobronchial lesion) 1
• Fever (due to post-obstructive pneumonia) 1

Symptoms Due to Primary Tumor Invasion or Regional Lymphatic Metastases

• Chest pain (42% of patients) 1, 2
• Hoarseness (due to left vocal cord paralysis from tumor invasion or lymphadenopathy) 1
• Hemidiaphragm elevation (due to phrenic nerve compression) 1
• Dysphagia (due to esophageal compression) 1
• Superior vena cava syndrome (13% of patients) 1, 2
• Pericardial effusion and tamponade 1
• Cervical or supraclavicular lymph node enlargement 1

Symptoms Due to Extrathoracic (Hematogenous) Metastases

• Brain metastases (present in 15% of patients at diagnosis) 1, 3:
  • Headache, focal weakness or numbness
  • Confusion, slurred speech
  • Gait instability, incoordination
• Leptomeningeal carcinomatosis:
  • Headache, confusion, cranial nerve palsy
  • Diplopia, slurred speech
  • Radicular back pain, spinal cord compression
• Adrenal metastases:
  • Mid-back or flank pain
  • Costovertebral angle tenderness
• Liver metastases (most common site of distant metastasis, occurring in 60% of metastatic cases) 1, 2:
  • Right upper quadrant pain or tenderness
  • Jaundice, fatigue, fever, hepatomegaly
• Bone metastases:
  • Bone pain
  • Spinal cord compression

Constitutional Symptoms

• Weight loss (30% of patients) 1, 2
• Weakness/fatigue (52% of patients) 1, 2
• Anorexia/cachexia 1

Paraneoplastic Syndromes

Paraneoplastic syndromes are particularly common in SCLC and may precede other symptoms:

Endocrine Syndromes

• SIADH (Syndrome of Inappropriate ADH secretion) 1:
  • Occurs in 5-10% of SCLC patients
  • Presents with malaise, weakness, confusion, obtundation
  • Laboratory findings: hyponatremia, euvolemia, low serum osmolality
• Cushing's syndrome (ectopic ACTH secretion) 1:
  • Less common than SIADH
  • Weight gain, moon facies, hypertension, hyperglycemia
  • Laboratory findings: high serum cortisol and ACTH

Neurologic Syndromes

• Lambert-Eaton myasthenic syndrome (proximal leg weakness) 1
• Encephalomyelitis (confusion, obtundation, dementia) 1
• Sensory neuropathy (pain, sensory loss) 1
• Cerebellar degeneration (ataxia, dysarthria) 1
• Cancer-associated retinopathy (visual loss, photosensitivity) 1

Clinical Presentation Pattern

Most patients with SCLC present with advanced disease, with approximately 70% having extensive-stage disease at diagnosis 3. The symptoms typically have been present for an average of 115 days before diagnosis, with cough (216 days) and dyspnea (150 days) being the most persistent symptoms 2.

Key Diagnostic Considerations

• Central hilar mass is present in 85% of cases 3, 2
• Mediastinal lymphadenopathy is present in 75% of cases 3, 2
• Distant metastases are present in 64.5% of patients at diagnosis 2
• Most common sites of metastases: liver (60%), lungs (35%), adrenal glands (30%), bones (15%), and CNS (15%) 2

Early recognition of these symptoms is crucial, as SCLC is an aggressive malignancy with rapid growth and early metastasis. The median survival without treatment is only 2-4 months from diagnosis, highlighting the importance of prompt evaluation of suspicious symptoms, especially in patients with a history of smoking.