Lung Cancer Overview

Case:

• 54 year old women presented for evaluation of abnormal X-ray
• Pulmonary History:  in 2000 developed newly positive PPD skin test. Chest Xray revealed “some spot” in Upper Right Lung. Txt w/ Isoniazid for 1 yr and X ray remained unchanged.

·         The area of suspicion is hard to read b/c of bony structures

• PMH
  • 35 pack year smoking history (1 pack/day for 35 years); Currently: 1 pack/day
  • Norm physical exam, PAP/pelvic, mammography last year
  • No symptoms, no cough, sputum, hemoptysis, weight loss, sweats, fevers or boney pains - pertinent negatives for TB
  • Normal cardiac & abdominal exam (normal liver & spleen size)
  • No clubbing or peripheral edema
• Current Xray

  
   

  • A pulmonary nodule is seen in the RU lobe of the lung. The Lateral film is more difficult to discern.
• CT Scan

  
   

  • On the CT scan we not a cavitated radio-opaque structure located in the mediastinum.
• In the Lung section: we see the density with spiculations (spike like opacities) suggestive of a lung neoplasm.
   

What is Lung Cancer?

• Uncontrolled growth of malignant cells in one/both lungs, and the tracheo-broncial tree
• Arise from protective or ciliated cells in the bronchial epithelium
• Begins as a result of repeated carcinogenic irritation which causes increased rates of cell replication
• Proliferation of abnormal cells leads to hyperplasia à dysplasia à carcinoma insitu
   

Incidence in US

• There are 170,000 new case of lung cancer yearly, more than 120,000 resulting in death that same year! That’s almost a 1:1 ratio
• More death from lung cancer than prostate, breast, and colorectal cancers COMBINED.
• Women account for more than half of new cases
  • More deaths from lung cancer than breast, ovarian, and uterine cancers COMBINED.
• Closely correlated with smoking patterns: there is decreased in incidence and deaths in men, but there is a continued increase in women.

Etiology of Lung Cancer

• Smoking
  • Tobacco is the leading cause of lung cancer
    • 80% of lung cancer is related to smoking
  • Risk related to:
    • dose dependent: amount smoked (pack years)
    • age of smoking onset
    • product smoked (Tar/Nicotine content. Filters)
    • Depth of inhalation
    • Gender: women are more susceptible to getting lung cancer based on size (smaller) which results in differences in exposure.
• Radiation Exposure
  • Uranium miners, or Radon have an increased correlation with lung cancer.
• Environmental/Occupational exposure
  • Asbestos: increases likelihood of getting a mesothelioma
  • Radon, Passive (2^nd hand) smoke

Lung Cancer Types

• Clinically (compared to Pathologically) there are 2 broad categories of Lung Cancer which behave differently
• Non Small Cell Lung Cancer (NSCLC)
  • Cancer that is treatable or curable by surgical intervention
  • Includes:
    • Adenocarcinoma (Bronchoalveolar cell carcinoma)
    • Squamous Cell Carcinoma
    • Large Cell Carcinoma
• Small Cell Lung Cancer (SCLC)
  • This cancer is not responsive to treatment with surgical resection
  • Chemotherapy is the major treatment choice
  •  

 
Clinical Presentation of Lung Cancer

• Local Symptoms (Cardinal Manifestation)
  • Cough, Dyspnea, Hemoptysis
  • Recurrent Infections (due to an obstruction in an airway)
  • Chest Pain (especially if the tumor is impinging on pleura, or the chest wall)
• Syndromes/Symptoms secondary to regional metastases
  • Dysphagia (due to esophageal compression)
  • Laryngeal nerve paralysis (hoarseness)
  • Pancoast Syndrome (Cervical/thoracic nerve invasion)
    • Horners syndrome (symptomatic nerve paralysis): small unreactive pupil, ptosis, anhidrosis
  • Pleural effusion (due to lymphatic obstruction. This is an example of exudative effusion)
  • SVC syndrome/ steal (Vascular obstruction)
  • Effusion tamponade (pericardial/cardiac extension)
• Symptoms Secondary to distant metastases (lymph nodes, brain, liver, lung/pleura, adrenal gland)
  • Pain
  • Organ related symptoms
• General Symptoms (silent metastasis)
  • Weight Loss & Fatigue
  •  

 
Paraneoplastic Syndromes

• Cancer cells can produce mediators which can cause unexpected secondary effects
• NSCLC
  • Hypercalcemia as a result of squamous cell carcinoma
  • Skeletal-connective tissue syndromes such as hypertrophic osteoarthropathy (the deposition of new bone), and clubbing.
• SCLC
  • Hyponatremia due to inappropriate secretion of ADH
  • Ectopic ACTH section
  • Eaton Lambert Syndrome is an example of a neurologic/myopathic syndrome that may present, and is characterized by muscle weakness.
     

Diagnosis

• H & P
• Diagnostic Tests
  • Chest XRAY is a key test!
    • Benign Nodules: a nodule that is unchanged in 2 yrs or is calcified (most likely a scar from a previous infection, such as TB); or a nodule that appears within less than 2 weeks is probably not cancer (more likely an infectious process)
    • Likely malignant: nodule that appears between 2 weeks and 2 years and gets bigger over time.
  • Biopsy (bronchoscopy, needle biopsy, surgery)
    • In a biopsy, the goal is to obtain a tissue sample.
    • Fiberoptic bronchoscopy: thread thru the nose, vocal cords, to the lung enabling the physician to directly visualize and biopsy a tumor.
      • The cancer presented in the case was in the upper lobe, and thus would be hard to reach with a bronchoscope. A needle can be placed through the chest wall, a surgical intervention.
      • Remember from anatomy that there are 16-23 areas of branching until the alveoli is reached.
      • Trachea (1) à Main stem bronchi (2) à Segment (3) à Subsegment (4) is as far as the bronchoscope can travel. Biopsy forceps would then have to be thread to reach the fifth and sixth generations of bronchi.
    • PET scan: is a new emerging test. The patient is given active metabolites (ex: glucose) which is taken up and metabolized by the cancerous cells. Though resolution of PET is much less than that of a CT scan, this shows the metabolic activity of cells and is indicative of a metabolically active disease.
• Staging Tests
  • CT chest/abdomen (important to see if there are any other nodules that may indicated metastasis)
  • Bone scan
  • Bone marrow aspiration
  • PET scan

NSCLC: TNM Staging

• Staging is important to determine protocol for a disease entity, and to enable the physician the ability to compare on patient to another to evalulate procedures and outcomes.
• Studying staging gives us an idea of whether a certain intervention will give a desirable outcome (Ex: surgery)
• Staging is based on TNM
• T =
•  tumor size
  • T1 <3cm; T2 > 3cm + atelectasis (reduction or absence of air in the lung)
• Tumor site
  • T3 – extension to pleura, chest wall, pericardium or total atelectasis
  • T4 – local involvement, invasion of the mediastinum or pleural effusion
• N= Lymph node spread
  • N1: broncho pulmonary; N2: ipsilateral mediastinal; N3: contralateral or supraclavicular
• M= Metastases

o        M0 – absence; M1 – presence

Stage  Ia      T1, N0, M0           

            Ib      T2, N0, M0                                                               

            IIa     T1, N1, M0                                                          

            IIb     T2, N1, M0

                     T3, N0-1, M0                                    

            IIIa    T1-3, N1, M0                                                       

            IIIb    Any T4, any N3, M0                                  

            Stage IV   Any M1      

• Treatment & staging
  • Stage IIIa and lower are curative cancers through means of surgery
  • Stage IIIb and higher (stage IV): not treatable by surgery, chemotherapy is often used.
    • If there is any sign of metastasis (diagnose using a PET scan) the cancer is a stage IV lesion
• What should we know? Basically we need to know whether to send our patient to a surgeon or to a radiation oncologist based upon their stage.

SCLC: TNM Staging

• Offers a sign of prognosis

• Limited Staging
  • Tumor is confined to one lung, all the cancer is in one radiation portal
  • Nodes can involve the contralateral lung
• Extensive Staging
  • Metastatic disease or disease not encompassed in one radiation field

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