Lung Cancer and Paraneoplastic Syndromes Quiz

Epidemiology of Lung Cancer

• Lung cancer is a prevalent cancer, especially among men, ranking as the second most common cancer in the Philippines.
• It is rare in individuals under 40, with incidence rising until age 80, then declining.
• The lifetime risk of developing lung cancer is estimated at ~8% for males and ~6% for females.
• Lung cancer has a high mortality rate due to late diagnosis, making it a leading cause of cancer deaths in the Philippines.

Risk Factors for Lung Cancer

• Cigarette smoking significantly increases lung cancer risk (10-fold or more).
• Occupational exposures contribute to risk.
• Smoking cessation, ideally before middle age, dramatically reduces lung cancer risk (by >90%).
• Genetic predisposition plays a role.

Lung Cancer Pathology

• Epithelial Lung Cancers:
  • Small-cell carcinoma (SCLC): Strongly associated with smoking.
  • Non-small cell carcinoma (NSCLC):
    • Adenocarcinoma: The most prevalent type in lifetime non-smokers or former light smokers. It accounts for 95% of NSCLC cases.

Clinical Manifestations of Lung Cancer

• Paraneoplastic Syndromes: Common in SCLC, can be the first sign of recurrence.
• Systemic Symptoms: Anorexia, cachexia, weight loss (poor prognosis), fever, immunosuppression.
• Endocrine Syndromes: Hypercalcemia, SIADH, Cushing's syndrome.
• Skeletal-Connective Tissue Syndromes: Clubbing (NSCLC), hypertrophic osteoarthropathy (common in adenocarcinomas, presenting with bone pain).
• Neurologic Syndromes: Eaton-Lambert syndrome (proximal muscle weakness, autonomic dysfunction), paraneoplastic cerebellar degeneration and encephalomyelitis.
• Thrombotic or Hematologic Syndromes: Trousseau's syndrome, nonbacterial thrombotic endocarditis, disseminated intravascular coagulation (DIC).
• Rare Manifestations: Dermatomyositis, acanthosis nigricans, nephrotic syndrome, glomerulonephritis, adrenal metastases.

Differential Diagnosis of Lung Cancer

• To rule in lung cancer, consider progressive symptoms, imaging findings, and pulmonary function tests (PFTs) to differentiate from conditions like COPD.
• To rule out lung cancer, consider a positive TB skin test or IGRA, cavitary lesions on chest X-ray, and positive sputum culture for tuberculosis when considering pulmonary tuberculosis.
• Pneumonia is ruled out via its acute onset, response to antibiotics, and consolidation indicated by chest X-ray or CT.

Diagnostic Workup for Lung Cancer

• Chest X-ray: Initial imaging test, detects large tumors, lung collapse, or fluid accumulation.
• CT scan: Precisely identifies tumor size, location, and involvement of adjacent tissues or lymph nodes; crucial for NSCLC staging.
• CT PET scan: Used for staging, metastasis detection, and identifying nodules >15 mm; often combined with CT (PET-CT); the gold standard for staging and metastasis detection.
• Sputum cytology: Non-invasive test detecting cancer cells in sputum or fluid samples.
• Biopsy: Tissue biopsy for definitive diagnosis, determining cancer type and characteristics; the gold standard for diagnosis.
• Bronchoscopy and Thoracentesis: Additional diagnostic procedures.

Principles of Lung Cancer Treatment

• Staging: Accurate TNM staging is crucial for treatment planning.
• Non-Small-Cell Lung Cancer (NSCLC):
  • Stages I & II: Surgery (lobectomy) is preferred; adjuvant chemotherapy for stages II & IIIA.
  • Stage III: Concurrent chemoradiotherapy.
  • Stage IV: Systemic therapy (chemotherapy, targeted therapy, immunotherapy based on genetic mutations).
• Small-Cell Lung Cancer (SCLC):
  • Limited stage: Concurrent chemoradiotherapy.
  • Extensive stage: Combination chemotherapy, with prophylactic cranial irradiation (PCI) for responders.
• Molecular and Targeted Therapy: Based on genetic mutations (e.g., EGFR, ALK).

Other Information Regarding Lung Cancer

• Palliative Care: Focuses on symptom management (pain, dyspnea, cough), nutritional and psychological support, and side effect management.