Updated: August 16, 2006

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 see Statistics by Cancer Type

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

• 85% of lung cancers are related to tobacco smoking
• People exposed to second-hand smoke over many years are also at risk
• In 1994, tobacco smoke was responsible for the deaths of 5,300 people in British Columbia. 53% of British Columbians worked in an environment where tobacco smoke was a risk.
• Exposure to uranium or other radiation sources. Heavy metals: chromates, arsenic, nickel
• Patients with history of chronic bronchitis or emphysema
• Asbestos dust
• People who have survived one lung cancer are at risk of a second cancer, particularly if they continue to smoke
• How Smoking Causes Cancer
  • Tobacco smoke contains many toxic chemicals capable of causing cancer
  • Hair-like cilia beat in rhythmic fashion to move the mucus upwards from the lung, removing any particles trapped in the mucus. Smoke inhalation damages this cleansing process by which the lung protects itself from injury
• A number of other factors, such as diet, may have an effect on the development of lung cancer; e.g. a low vitamin A intake may be associated with increased risk
• However, beta-carotene supplements increase lung cancer risk

Prevention

• Prevention (never smoking) holds the greatest hope for the future
• Quitting smoking is the single most important action you can take to protect your health
• Quitting smoking does little to restore lost lung function, but quitting will help slow the rate of decline in lung function
• Quitting also decreases the risk of heart attack, stroke and coronary heart disease.

Diagnosis

• Pulmonary function tests to determine volume of air inhaled and exhaled
• Chest X-ray is the single most useful examination but only 10% of diagnoses come from routine chest X-rays as a part of a general physical examination
• CT (computerized tomography) scans are used to show the relationship of the lung cancer to other structures of the chest and possible spread to lymph nodes
• MRI (magnetic resonance imaging) not superior to CT scans for thoracic imaging but may be useful in some circumstances
• Pulmonary cytology, the microscopic examination of samples of sputum obtained from the bronchial passages, or the pleural fluid, can now provide a definitive diagnosis in 80% to 90% of patients
• Needle biopsy may be performed when other sampling techniques fail to provide a diagnosis. The doctor, guided by X-rays inserts a long needle into a suspected tumour and withdraws a tissue sample. Lung collapse may be a complication
• Bronchoscopy is a procedure in the diagnosis and determination of the extent of the disease. Usually performed with a fibre-optic bronchoscope - a flexible tube with lighting and magnifying devices which is inserted down the throat into the trachea and bronchi. A biopsy of tissues may be taken at this time. A local or general anesthetic may be used
• Mediastinoscopy and mediastinotomy: These procedures are performed under general anesthetic. A mediastinoscope is inserted through a small v-shaped incision at the center of the base of the neck and passed behind the sternum (breastbone) to lie directly in front of the trachea. Lymph nodes on either side can be seen and biopsied. Mediastinotomy involves an incision and removal of some of the 2nd rib cartilage for patients who have centrally located tumours in the left upper lobe, to gain access to the lymph nodes under the aorta
• Pleuroscopy is infrequently used but valuable for patients who have undiagnosed fluid in the chest. A thoracoscope or fibre-optic bronchoscope is inserted into the pleural space. All of the space can be examined visually and fluid and tissue samples can be withdrawn
• Thoracentesis: the removal of fluid from the chest by inserting a needle in the space between the lung and the chest wall. May be used for fluid analysis or to relieve shortness of breath caused by the collection of large amounts of fluid in the pleural space. Occasionally combined with a procedure to stick the lung to the chest wall called a pleurodesis. This usually involves the placing of a tube in the chest for one to three days during a hospital stay to ensure that all of the fluid has been removed
• Diagnostic thoracotomy: surgical opening of the chest may be necessary if other diagnostic procedures fail
• Lymph node biopsy from nodes in the neck may be performed

Screening

• A chest x-ray or the examination of three or four sputum samples for malignant cells are traditional methods which may detect early cancer of the lung
• The BC Cancer Agency is currently enrolling people in a project called the Lung Health Study. The focus of the study is the early detection of lung and bronchial cancer, and the identification of new agents that may halt or slow the growth of abnormal cells in these organs
• Eligibility for Lung Health Study:
  • a former smoker
  • between 45-74 years of age
  • have smoked at least 30 years or more
• The Lung Health Study uses a lung imaging fluorescence endoscope (LIFE), a light sensitive camera attached to a bronchoscope, to detect pre-cancerous areas and/or early lung cancers too small to detect on chest x-rays or by conventional bronchoscopy alone
• The LIFE system illuminates the airways with a blue laser light and a computer analyzes the images and displays them on a colour monitor
• A physician can then differentiate abnormal areas, shown as red, from normal areas, shown as green
• Tiny tissue samples are taken from abnormal areas (for pathological confirmation of diagnosis)
• People who are discovered to have abnormalities will be invited to participate in a chemoprevention trial
• For additional information contact the Lung Health Study, B.C. Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3 (phone 604-675-8088 or 1-888-675-8001 local 8088)

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.

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 origin.

Treatment

• Standard Treatments are Surgery, Photodynamic Therapy, Radiation therapy, and Chemotherapy
• Early lung cancers may be treated with a relatively simple laser therapy
• Treatments that are not useful in lung cancer include Immunotherapy, Hyperthermia and Bone marrow transplantation

Surgery

• Effective with small, localized tumours with no spread outside lung
• Sometimes performed to relieve symptoms. Sometimes followed by radiation treatment
• This is major surgery and is done under general anesthesia - 2-3 hours and requires 1-2 weeks hospital
• Procedures:
  • Thoracotomy - chest cavity is opened for the purpose of diagnosis
  • Lobectomy - removal of a lobe of one lung
  • Pneumonectomy - removal of an entire lung
  • Segmented or wedge resection - removal of part of a lobe of one lung
• Long term (five year) cure expected in only one-third at best

Photodynamic Therapy (PDT)

• Also known as Photochemotherapy; Laser Therapy; Hematoporphyrin Derivative (HpD); Photoradiation Therapy
• Photodynamic therapy refers to the use of photo (light) sensitizing drugs, e.g. Fotofrin which, when injected intravenously into the patient, acts selectively to kill cancer cells when they come in contact with red light from a laser.

Indications:

• Used primarily for bronchial cancer. (Dr. Stephen Lam, BC Cancer Agency)
• Certain bronchial wall and other operable, obstructive, residual or recurrent bronchial tumours
• For treatment of bronchial cancer with positive sputum cytology (cancer present) but of unknown precise location. The Fotofrin which is selectively located in the cancer cell "pin-points" the location of the tumour when the light from the endoscope reaches it. Although very few patients have a positive sputum cytology with unknown precise location of the tumour, for those patients, PDT is very useful for early cancer treatment as well as early detection of cancer
• Early detection of bronchial or certain lung cancers, particularly for smokers of high risk
• At present, not a curative treatment for cancers deeper in the bronchi than light can penetrate. Cannot be used to treat widespread disease

Procedure:

• The photosensitizing drug Hematoporphyrin Derivative (HpD) is first injected intravenously into the patient
• The patient is bronchoscoped (bronchoscope used to view the bronchi via a flexible light carrying tube) 24-48 hrs after injection
• By this time, the drug is largely washed out of normal tissue but retained preferentially in tumour cells
• A red laser light is conducted to the tumour area by the bronchoscope via a fine quartz fibre
• Illumination of the tumour by the red laser light activates the HpD within the tumour cells, producing free oxygen which causes cancer cells to die over the next 24-48 hours
• The procedure may be repeated for larger-sized tumours

Radiation Therapy

• Given externally using a cobalt machine or a linear accelerator. The aim can be curative or palliative
• For certain patients, radiation treatment may be a curative choice when surgery is refused by the patient or if it is contraindicated because of medical problems, age of patient, etc.
• It is also given as an adjuvant to surgery when there is a possibility of residual disease
• Palliative radiotherapy may be given when cure is not possible because of the extent of the disease, to relieve symptoms such as cough, haemoptysis (blood in the sputum), chest pain and dyspnea (shortness of breath)
• Palliative radiotherapy can also be given to other parts of the body to relieve symptoms such as those arising from spread to the brain or bones
• Intensive radiotherapy integrated with chemotherapy may be appropriate for some patients with locally advanced but not widespread lung cancer

Chemotherapy

• Treatment of choice for small cell or oat cell carcinoma (combined with radiotherapy)
• For non-small cell types, palliative chemotherapy is an option that may be associated with temporary symptom control, improvement in quality of life, and a gain in survival time but widespread disease cannot be cured with drug therapy. Because non-small cell lung cancer is often resistant to chemotherapy, benefits for individual patients are uncertain
• Investigational chemotherapy protocols for non-small cell lung cancer may be available at BCCA clinics
• May be used to reduce the size of the tumour and to relieve symptoms
• Non-small cell lung cancer is often resistant to chemotherapy and benefits for individual patients are uncertain

Laser Therapy

• Can be used to open the airways when they are blocked by a tumour

Follow Up

• All successfully treated patients must stop smoking because second primary lung cancers are common
• Recurrences not curable
• Routine tests include clinical examination and chest X-ray
• Chemotherapy may be considered for treatment of recurrent thymoma