Lung Cancer Part 2 (Diagnosis, Complications, & Staging)

Overview

  • Primary lung tumors can cause chest pain, cough, dyspnea, and hemoptysis, particularly in the later stages. Early stages are often asymptomatic, which contributes to the difficulty in early diagnosis.
  • Complications of lung cancer depend on the location and/or cell type of the tumors.
  • Diagnosis
    – Initial diagnosis is via chest x-ray or CT scans, and is often incidental.
    – Sputum collection and biopsies are performed so that histopathology and molecular analyses can tell us the type of lung cancer.
    –Unfortunately, many patients are diagnosed in advanced stages, when metastasis has already begun and prognosis is poorer.
    –Thus, screening is recommended for high-risk individuals (patients with a history of heavy smoking and who are between 55 and 80 years old).
  • Treatment
    – Varies by patient, cancer type, and stage; list the following options, which are often combined for maximal efficacy:
    Surgical removal of tumor
    Radiation
    Chemotherapy
    Targeted drug therapy – this is particularly useful in non-small cell lung carcinomas harboring specific genetic mutations – for example, Tyrosine Kinase Inhibitors (such as erlotinib and gefitinib) are effective for patients with EGFR mutations, and ALK inhibitors (such as crizotinib) for ALK mutations.
    Targeted therapies are celebrated for their relative safety and tolerability, since they only act against cancer cells; however, be aware that resistance to targeted inhibitors can occur,which is another reason for combination therapy.
    Immunotherapy is another form of targeted therapy; immune checkpoint inhibitors (such as nivolumab) amplify the immune response to cancer cells.

Paraneoplastic syndromes and complications

Small-cell lung cancer

  • Ectopic Cushing syndrome; we draw a “moon face” to remind ourselves that Cushing syndrome is caused by over-secretion of ACTH and is associated with fat accumulation in the head, neck, and trunk, which can produce an exaggerated roundness in the face.
  • SIADH (syndrome of inappropriate anti-diuretic hormone secretion); remind ourselves that this leads to retention of body water and, therefore, reduced urine output.
  • Lambert-Eaton myasthenic syndrome and other immune-mediated neurologic syndromes. To illustrate this, show antibodies attacking the neuromuscular junction

Adenocarcinoma

  • Nonbacterial verrucous endocarditis.

Squamous cell carcinoma

  • Hypercalcemia due to production of parathyroid hormone-related protein; common symptoms of hypercalcemia include weakness, nausea, vomiting, abdominal cramps, and dehydration.

Large cell lung cancer

  • Gynecomastia.

Non-small cell lung cancers, as a group

  • Hypertrophic pulmonary osteoarthropy, (aka, Marie-Bamberger syndrome), which is a rare condition comprising the following triad: periostitis, arthropathy, and digit clubbing.

Small and Non-Small lung cancers

  • Hematological disorders including anemia, disseminated intravascular coagulation, granulocytosis (increased granulocytes), and thrombocytosis (increased platelets).
  • Dermatomyositis

Complications of lung cancer more broadly

  • *Superior vena cava syndrome is obstruction of blood flow through the superior vena cava due to direct tumor invasion or external compression of the vessel.
    – Patients present with facial and neck swelling, edema, and jugular venous distention.
    – SVC syndrome is more likely to occur in small-cell lung cancer, but, because non-small cell lung cancer is more common than small-cell, it is a frequent cause of SVC syndrome.
  • Pancoast tumors, aka, superior sulcus tumors, occur when tumors at the lung apex compress nearby structures.
    – We think about Pancoast tumors in brachial plexopathies, which cause shoulder pain and weakness, and also in proximal ulnar neuropathies, which cause weakness and atrophy of the intrinsic hand muscles.

– Pancoast tumors are also responsible for Horner syndrome, which is characterized by ptosis (eyelid drooping), miosis (pupil constriction), and facial anhidrosis (lack of sweating).

  • Lastly, indicate that lung tumors can cause compression of the recurrent laryngeal nerve (from CN 10)

STAGING

  • Tumor staging determines treatment options and prognosis. Staging can involve imaging studies as well as surgical resections and biopsy.

Non-Small Cell Lung Cancer

  • Uses the TNM system to asses Tumor size/invasiveness, lymph Node involvement, and Metastasis to distant sites.
  • The stages I-IV progress from cancer in the lungs, then the lymph nodes, then other body sites.
  • Stage I: tumor is present only in the lungs (no lymph node involvement or metastasis).
  • Stage II: tumor is present in the lungs and there is nearby lymph node involvement (but no metastasis).
  • Stage IIItumor in the lungs is accompanied by cancer in the lymph nodes in the middle of the chest (but no metastasis).
    –Stage IIIa involves lymph nodes on the same side as the original tumor.
    – Stage IIIb involves lymph nodes on the opposite side.
  • Stage IV tumors are in both lungs, the pleural fluid, and/or has metastasized (most often to the brain, liver, or bones).

Small-cell Lung Cancer

  • Staging is much simpler.
  • Limited stage: in which tumors lie within the ipsilateral hemithorax (tumors on one side of the chest only) and can be encompassed within a single radiation port.
  • Extensive stage: metastatic cancer that involves both sides of the chest or is present in pleural or pericardial effusions.

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