2 Lung Cancer

7/29/2019 2 Lung Cancer

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Lung cancer



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.



Epidemiology-USA



Epidemiology-USA



Epidemiology-USA



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



• 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.



• 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



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



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



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%)



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)



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



Extension

• Lymphatic-

-hilar

-mediastinal

(drainage crosses to the

other side to)

-scalene, supraclavicular



Extension

• Metastases-

-brain

-bone

-liver

S t



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



Symptomsd) Extrathoracic metastases

-brain

-liver

-bone

-suprarenals (asthenia)

e) General symptoms (weight loss, asthenia)

f) Paraneoplastic syndromes



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



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



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



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



Questions

• What are the risk factors of lung cancer?

• What are the symptoms of lung cancer?

• How is non-small cell lung cancer treated?

Documents

2 Lung Cancer