2 lung cancer
TRANSCRIPT
7/29/2019 2 Lung Cancer
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Lung cancer
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Epidemiology
• Incidence: Lung cancer
is the most common
cancer in the world
• Mortality: is the leading
cause of cancer deaths
in both men and
women
• RO:
-males: 4.
-females: 1.
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Epidemiology-USA
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Epidemiology-USA
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Epidemiology-USA
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Etiology (risk factors)
I. Environmental
1. Smoking is the primary risk factor for lung
cancer accounting for 90% of cases in men
and 70% in women
• It is a risk factor for both NSCLC (squamous
cell carcinoma, adenocarcinoma, large cell
carcinoma) and SCLC
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• In the US: Adenocarcinoma has been more common thansquamous cell carcinoma in women since the 1950s andbecame the most common lung cancer diagnosis in men in1990.
• There are many theories that may explain a relativedecrease in squamous and small cell carcinomas and theincrease in adenocarcinomas. The introduction of filter cigarettes in the mid-1950s may have contributed:
1. by allowing smaller carcinogens to be deposited in the lungperiphery.
2. may have determined smokers to take larger puffs and retainsmoke longer to compensate for the lower nicotine yield
Plus, smoking low-tar filter cigarettes may increase the rate of adenocarcinoma because these cigarettes have a higher nitrate content, which has been shown to produceadenocarcinoma in laboratory animals.
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• Men who smoke one pack a day increase their risk 10
times compared with non-smokers.
• Men who smoke two packs a day increase their risk
more than 25 times compared with non-smokers• The lifetime risk of developing lung cancer in
smokers is approximately 10%
•
Cancer risk decreases slowly after quitting: 40% of newly diagnosed lung cancer occurs in former
smokers (median abstinence duration 9 years)
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Etiology2. The second most important environmental risk factor
is Rn (Radon)
=a radioactive gas
-from rocks
-represents 40% from the background radiation
-it is deposited in the airways
-deposition in airways increased if bound to aerosols (for
example smoke); smoking increases deposition 25
times
3. Asbestos- increases risk both for lung cancer and
mesothelioma (of the pleura or peritoneum)
4. Exposure to radiation
e.g. radiotherapy for breast cancer
i l
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Etiology5. Industrial pollutants (Ni, Be)
II. Genetic predisposition
Why not all people who smoke develop lung cancer?
- genetic polymorphism or deletion of genes of enzymes
playing a role in detoxification of polycyclic aromatic
hydrocarbons found in tobacco smoke
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Classification
• Non-small cell lung cancer=NSCLC (80%)-consists of 3 main types:
– Squamous cell carcinoma
–
Adenocarcinoma – Large cell carcinoma
• Small cell lung cancer=SCLC (=oat cell cancer)
(20%)-different behavior (more aggressive)
-early metastases
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Special subtype: bronchioloalveolar carcinoma
• Rare: 2-9% of primary lung cancers
•Related to adenocarcinoma
• At first it is non-invasive tumor (carcinoma in situ), but eventually
can produce metastases
• Tumor cells spread along the alveoles
=>Produces dyspnea in a restrictive (not obstructive) way
• Smoking is a risk factor,
but it is less important than in
other histological subtypes
• Radiologic patterns:
peripheral solitary nodule (43%);
consolidation (30%),
or diffuse disease (27%)
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Extension
•
Local:-invasion of the big mediastinal vessels
-invasion of the pericardium
-invasion of the laryngeal recurrent nerves-invasion of the pleura
-invasion of chest wall (e.g. Pancoast tumor)
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Pancoast tumor
=superior sulcus tumor
=malignant neoplasm of the thorax inlet with invasionof the chest wall and involvement of the brachialplexus and cervical sympathetic nerves.
Symptoms:
- severe pain in the shoulder region radiating towardthe axilla, scapula and along the ulnar aspect of themuscles of the hand
- atrophy of hand and arm muscles
- Bernard-Horner syndrome (compression of sympathetic chain)
- compression of the subclavian vein with oedema
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Extension
• Lymphatic-
-hilar
-mediastinal
(drainage crosses to the
other side to)
-scalene, supraclavicular
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Extension
• Metastases-
-brain
-bone
-liver
S t
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Symptomsa) Endobronchial tumors
-cough, obstructive dyspnea, hemoptisis, obstructive
pneumoniab) Peripheral tumors
-longer asymptomatic evolution
-pleural invasion=>pleuritic pain and cough; restrictive dyspnea;
pulmonary abscess formation
c) Compression/invasion of mediastinal/thoracic structures by
primary tumor or lymph nodes
-tracheal obstruction; dysphagia; dysphonia; paralysis of a
hemidiaphragm by invasion of a phrenic nerve; superiorvena cava obstruction; dyspnea by pleural exudate/or
transsudate;
S t
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Symptomsd) Extrathoracic metastases
-brain
-liver
-bone
-suprarenals (asthenia)
e) General symptoms (weight loss, asthenia)
f) Paraneoplastic syndromes
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Diagnosis
• Chest radiography
• Chest and upper abdominal CT or PET-CT
(MRI not good for mobile organs such as the lung)
• Endobronchial biopsy or transbronchial biopsy
•
Mediastinoscopy or thoracoscopy with biopsy for tumors notbiopsiable bronchoscopically
• Pleural liquid, if present, must be tested for malignant cells-
important for staging and thus treatment
•
Brain MRI• Pulmonary function testing
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Treatment-NSCLC
• Resectable tumor=> lobectomy/unilateral pneumonectomy
plus mediastinal lymphadenectomy
+/- adjuvant chemotherapy or radiotherapy
• Unresectable tumor=> concomitant chemoradiation with or
without reevaluation for surgery
•
Metastatic lung cancer=>chemotherapy• Endobronchial obstruction=> palliative desobstruction with:
-stent
-LASER
-brachytherapy or external beam RT-photodynamic therapy
• Superior vena cava obstruction:
-emergency palliative external beam radiotherapy or stent
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Treatment-SCLC
LIMITED-STAGE DISEASE=SCLC which is limited to a hemithorax
and can be encompassed in one tolerable radiation field
• Stage I disease (only 5% of patients) (true stage I is after
extensive testing, including mediastinoscopic
lymphadenectomy)=> lobectomy
• Other limited disease=> chemoradiation
EXTENSIVE-STAGE DISEASE
• Chemotherapy
• All patients who are in complete or partial response:
prophylactic cranial irradiation
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Screening
• Stage I lung cancer can be diagnosed using
annual low dose CT scans
• No screening programs implemented yet;
studies ongoing
• Warning: 1000 CTs of chest/abdomen=> 1
radio-induced cancer
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Questions
• What are the risk factors of lung cancer?
• What are the symptoms of lung cancer?
• How is non-small cell lung cancer treated?