http://www.bccancer.bc.ca/PPI/Typeso...ng/default.htm
General Information / Anatomy / Function / Statistics
* Lungs are situated in the chest (thoracic cavity)
* They wrap around the heart and major blood vessels going to and from the
heart and esophagus
* The right lung has three sections, or lobes, and the left lung has two
* The lungs and inner walls of the chest are covered with a thin double
membrane called the pleura, normally touching and moving easily during
breathing
* Air is inhaled through the nose into the pharynx (back of the throat),
the trachea (windpipe), and finally into the mainstem bronchi
* The bronchial tubes or bronchi branch into smaller tubes within each
lobe and again into bronchioles ending in the alveolar ducts
* Alveolar ducts lead to tiny thin-walled clusters of sacs called alveoli
* Average lung has about 300 million alveoli
* The exchange of oxygen and carbon dioxide takes place in the alveoli
where blood capillaries are present
* Lung cancer is the second most frequent type of cancer diagnosis for
both men and women
* Lung cancer is the most common cause of cancer death for both men and
women in North America, accountable for approximately 27% of cancer mortality
* Majority of patients have extensive disease at the time of diagnosis
* If diagnosed early, lung cancer can be eradicated in over 90% of
patients
* Occurs most often in the 55 to 70 year age group but in recent decades
incidence has increased two-fold in the 40 to 44 year old group and ten-fold
in the 60 to 64 year group
* Common sites for lung cancer metastases are brain, liver, bone and lymph
nodes
* For statistics, please click here
Symptoms / Signs
* No symptoms in early stages
* Symptoms in the more advanced stages include:
Chronic cough (smoker's cough)
New or changing cough, particularly if the sputum contains
blood
Change in lung function
Blood in sputum, even small amounts
Wheezing (unrelated to asthma), hoarseness
Repeated episodes of pneumonia or bronchitis
Fever, weakness, weight loss
Chest pain
Difficulty in swallowing
Enlargement of lymph nodes in neck
Up to 12% of patients have "clubbing" or broadening of the
fingernails
About 12% of patients have pleural effusion or fluid in the
lungs at the time of diagnosis
Infection is a common complication
Collapse of a segment, lobe, or all of a lung (atelectasis)
Obstructive pneumonitis occurs in 60% of all patients
* Symptoms from metastases may occur before symptoms from the lung disease
Etiology / Carcinogens / Risks (see web page)
How Smoking Causes Cancer (see web page)
Prevention (see web page)
Diagnosis (see web page)
Screening (see web page)
Staging
* The disease is classified according to the extent of the primary tumour
(T) the status of regional lymph nodes (N) and distant spread or metastases
(M)
* The extent of the cancer in each of these important areas is then
described by means of a simple code in which numbers designate the absence of
tumour or increasing levels of disease; e.g., T1 T2 T3 T4 N0 N1 M0 etc.
Stage I tumour can be removed surgically; has not spread to the
lymph nodes
Stage II has spread to lymph nodes within the lung
Stage III the nodes in the center of the chest are involved. Primary
tumour invades the chest wall or central structures within the chest.
Stage IV the cancer has spread to distant sites
Types
Small cell lung cancer (SCLC)
* Undifferentiated small cell or "oat cell"
* 20-25% of lung cancers
* Generally small and round, or oval, or shaped like oat grains
* Most aggressive of all lung cancers
* Many patients have distant metastases at time of diagnosis even if
primary is small
* Generally not treated surgically
* Multidrug chemotherapy integrated with radiation therapy is the usual
treatment
* Long term cure possible (20%), if tumour is localized to the chest
* Prophylactic brain radiotherapy usually employed in curative therapy
Non-small cell lung cancer (NSCLC)
* Includes squamous cell, adenocarcinoma, and large cell undifferentiated
cancer.
Squamous cell (epidermoid)
* 30% of lung cancers
* Precancerous phase may last several years during which abnormal, but not
cancerous cells are found in the sputum but chest X-rays are normal
* In later stages the lung tumour can be seen on X-rays or it grows large
enough to cause symptoms
* Commonly arise in the larger lobar and segmental bronchi of the central
part of the lung
* Patients respond better to treatments with surgery and radiotherapy than
do those with other types of lung cancer
Adenocarcinoma
* 40% of lung cancers are adenocarcinomas
* More common in women
* Most frequent type seen in non-smokers
* Tumour cells form recognizable glandular structures
* Higher risk of lymphatic and blood spread
* The most frequently diagnosed peripheral cancer
* Often associated with scarring of the lungs
* May be seen as a subpleural mass that invades the overlying pleura
* Prognosis, except for patients with early stage tumours, is poorer than
for squamous cell carcinoma
* A subtype of adenocarcinoma called bronchioalveolar or alveolar cell
lung cancer arises from the terminal bronchioles alveoli walls. Less
associated with smoking
Large cell carcinoma
* Occur less frequently than other cell types (10%)
* Generally behave like adenocarcinomas, with aggressive spread
The lung is also a common site for metastases, spread from a primary cancer
located elsewhere in the body (e.g. breast, bowel, kidney pancreas, etc).
Therapy for metastatic lung cancer is determined by the site of the cancer's
origi
types of lung cancer 
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