Lung Flashcards
Epidemiology of lung cancer
Most common invasive malignancies in the United States
The male to female ratio has reached 1:1, compared to the 6:1 ratio in 1960
Lung cancer has surpassed breast cancer in the leading cause of cancer-related deaths in women.
Risk factors for lung cancer
Significant tobacco exposure is defined as more than one pack of cigarettes per day. Occupational exposures: - coal tar - nickel - chromium - arsenic - radon Asbestos has been shown to cause mesothelioma
Anatomy of the trachea
The trachea is the major airway.
The trachea begins at the lower end of the larynx and ends at T5 where it bifurcates (carina)
The wall is composed of rings of cartilage, smooth muscles and connective tissues.
Epithelial cells line the trachea.
Anatomy of primary bronchi
Divides into right and left bronchi at the level of T4/T5 where the trachea bifurcates.
Form branches of decreasing size until finally reaching the microscopic level where the gases are exchanged.
Hilum
Area of the lung where the blood vessels and lymphatics enter and exit the lung.
Two categories of lung cancer
Small cell
Non-small cell
* mesothelioma is distinct although less frequent cetergory
Pathology of non-small cell lung cancer
Non-small cell
- adenocarcinoma
- squamous cell carcinoma
- large cell adenocarcinoma
Most common signs and symptoms of lung cancer
Cough: the initial symptom of lung cancer. Noted in 30-75% of lung cancer.
Dyspnea (shortness of breath): occurs in 20-60% of patients
Chest pain: not a good prognosis due to the extent of the tumour
Hemoptysis: blood in sputum
Hoarseness: usually indicates the mediastinal extension
Weight loss: can be a sign of advanced disease
T1 stage non-small lung cancer
T1a: <2cm does not invade the main bronchus
T1b: >2cm but <3cm does not invade the main bronchus
T2 stage non-small lung cancer
T2a: >3cm but <5cm involves the main bronchus or invades visceral pleura >2cm from carina
T2b: >5cm but <7cm involves the main bronchus or invades visceral pleura >2cm from carina
T3 stage non-small lung cancer
> 3cm invades chest wall, diaphragm, mediastinal pleura or parietal pericardium or tumour in the main bronchus, <2cm from distal carina but without the involvement of carina
N1 stage non-small lung cancer
Positive ipsilateral peribronchial +/- hilar lymph nodes
N2 stage non-small lung cancer
Positive ipsilateral mediastinal +/- subcarinal nodes
N3 stage non-small lung cancer
Positive contralateral mediastinal or hilar nodes or ipsilateral +/- contralateral scalene or superclav nodes.
Small cell lung cancer staging
Limited: confined to hemithorax
Extensive: spread beyond the thorax, mets and pleural effusion
Superior mediastinal lymph nodes
Upper paratracheal Lower paratracheal nodes Tracheobronchial angle nodes Aortic nodes are also included: - aortopulmonary - anterior mediastinal nodes
Inferior mediastinal nodes
Subcarinal nodes
Paraesophogeal nodes
Pulmonary ligament nodes
Symptoms of local disease lung cancer
Weight loss is an early symptom
Cough that is more severe than normal
Hemoptysis (blood associated with the cough)
Symptoms of regional disease lung cancer
Regional invasion into the surrounding lymph nodes symptoms may include:
- pain
- coughing
- dyspnea
Disease extension into the mediastinum may cause:
- dysphagia (due to esophageal compression)
- superior vena cava syndrome (dyspnea, swelling in neck, face and arm)
- hoarseness (due to compression of the larynx)
Pancoast tumour
Located in the apex of the lung although other criteria must be met to be diagnosed with a Pancoast tumour.
- pain around the shoulder and down the arm
- atrophy of the hand muscles
- Horner syndrome
- bone erosion of the ribs and sometimes vertebrae
Horner syndrome
Due to the Pancoast tumours involvement of the cervical sympathetic nerves.
Classically includes:
1. ipsilateral miosis (contracted pupil)
2. ptosis (drooping eyelid)
3. enophthalmos (recession of the eyeball into the orbit)
4. anhidrosis (loss of facial sweating)
Symptoms of metastatic disease lung cancer
Generally associated with anorexia, weight loss and fatigue.
Paraneoplastic syndrome
Paraneoplastic syndrome
Disorder arising from the metabolic effects of cancer on tissues remote from the tumour.
May appear as an endocrine, hematologic or neuromuscular disorder.
Screening of lung cancer
High-risk individuals may qualify for a low-dose CT screening. Has been shown to reduce the mortality rate from lung cancer for those between the ages of 55 and 74 years with a history of at least a 30-pack year history.
Fiberoptic bronchoscopy
A long flexible tube that can be used to identify up to 75% of lesions.
Can also be used to obtain a specimen for biopsy.
Endoscopic bronchial ultrasound scan
Less invasive allows physicians to view and biopsy regions that used to be done by invasive surgery.
Involves the insertion of a bronchoscope into large airways. After the tube is placed the ultrasound probe at the end of the probe is used to examine surrounding areas.
Squamous cell carcinoma of the lung
- etiology
- epidemiology
- location
Usually associated with tobacco consumption and are more commonly centrally located in the proximal bronchi. More common in men.
Adenocarcinoma cell carcinoma of the lung
- epidemiology
- location
More common in women and are frequently more peripheral locations.
Small cell carcinomas of the lung
- location
- spread
Centrally located
More prone to early spread and fewer than 10% of patients are diagnosed with limited-stage.
Large cell carcinoma of the lung
- location
Peripherally
Direct spread of lung cancer
Most likely to spread to: - other parts of the lung - ribs - heart - esophagus - vertebral column A tumour that is not encapsulated may invade and attach itself to structures such as the chest wall, diaphragm, pleura, and pericardium (T3 or T4 stage tumour)
Common sites for lung metastasis
Most commonly occur:
- cervical lymph nodes
- liver
- brain
- bones
- adrenal glands
- kidneys
- contralateral lung
Surgery considerations lung cancer
Patients that can handle the surgery and have stage I or II diseases should be considered for definitive surgery. (only 20% of patients is this recommended)
Lobectomy with regional lymph nodes sampling is considered the best option.
A limited wedge resection with video-assisted thoracoscopy is also utilized with good rates of regional control.
Lesions that are central with the mainstem bronchus necessitate a total pneumonectomy.
Standard ChemoRT therapy for non-small cell lung cancer
Concurrent, sequential or alternating chemotherapy and radiation.
With radiation doses between 4500cGy and 6000cGy at 180 or 200cGy per fraction.
Critical structures consideration for treatment of lung cancer
Spinal cord: 4500cGy
Esophagus
Heart: 3000cGy leads to a 50% chance of pericarditis
Healthy lung
Treatment volume POP lung cancer
Typically includes the primary tumour volume with a 2.0cm-2.5cm margin of healthy tissue.
If a superior tumour or involves the mainstem of the bronchus ipsilateral supraclavicular lymph nodes should be included. Ipsilateral hilar and superior mediastinal lymph nodes should be included with a 2.0cm margin and at least 5cm below the carina.
If an inferior tumour the field should extend to T10 or the diaphragm.
TDF treatment of small cell lung cancer
RT alone: 60Gy/30#
ChemoRT: 54-60Gy/30#
Prognosis of lung cancer
The prognosis of small cell lung cancer is poor with only 10-15% of patients surviving 3 years.
Non-small cell lung cancer has a better prognosis with 15-20% of patients surviving 5 years.
Survival is significantly better with the early-stage disease when surgery can be done for curative intent.
