2. Lung cancer is the most common cause of death from
cancer worldwide, causing 1.59 million deaths per year.
Tobacco use is the major preventable cause, Just as
tobacco use and cancer rates are falling in some developed
countries, both smoking and lung cancer are rising in
Eastern Europe and in many developing countries.
The great majority of tumours in the lung are primary lung
cancers
in contrast to many other tumours, the prognosis remains
poor, with fewer than 30% of patients surviving at 1 year
and 6-8% at 5 years.
3. Primary tumours of the lung
Etiology
Cigarette smoking is by far the most important cause of lung cancer. It is thought to be
directly responsible for at least 90% of cases, the risk being proportional to the amount
smoked and to the tar content of cigarettes.
The death rate from the disease in heavy smokers is 40 times that in non-smokers.
Risk falls slowly after smoking cessation but remains above that in non-smokers for
many years.
It is estimated that 1 in 2 smokers dies from a smoking-related disease, about half in
middle age.
The effect of 'passive' smoking is more difficult to quantify but is currently thought to
be a factor in 5% of all lung cancer deaths. Exposure to naturally occurring radon is
another risk.
4. Lung cancer
The incidence of lung cancer increased dramatically during the 20th
century as a direct result of the tobacco epidemic
In women , smoking prevelance and death from lung cancer
continue to increase
5. Pathology
Lung cancers arise from the bronchial epithelium or mucous glands.
When the tumour occurs in a large bronchus, symptoms arise early but tumours
originating in a peripheral bronchus can grow very large without producing
symptoms, resulting in delayed diagnosis
Peripheral squamous tumours may undergo central necrosis and cavitation and may
resemble a lung abscess on X-ray.
Lung cancer may involve the pleura directly or by lymphatic spread and may
extend into the chest wall, invading the intercostal nerves or the brachial plexus and
causing pain. Lymphatic spread to mediastinal and supraclavicular lymph nodes
often occurs before diagnosis.
.
6. Blood-borne metastases occur most commonly in liver, bone, brain,
adrenals and skin. Even a small primary tumour may cause widespread
metastatic deposits and this is a particular characteristic of small-cell
lung cancers.
7.
8.
9. Cells of origin of lung cancer
Neuroendocrine cells :small cell carcinoma
Basal cells in major bronchi : squamous cell carcinoma
Mucus gland in terminal bronchioles: adenocarcinoma
10. Clinical features
Lung cancer presents in many different ways, reflecting local, metastatic or
paraneoplastic tumour effects.
Cough This is the most common early symptom. It is often dry but secondary
infection may cause purulent sputum. Achange in the character of a smoker's
cough, particularly if associated with other new symptoms, should always
raise suspicion of lung cancer.
Haemoptysis Haemoptysis is common, especially with central bronchial
tumours, Although it may be caused by bronchitic
11. Breathlessness Breathessness may be caused by collapse or pneumonia, or by tumour causing a
large pleural effusion or compressing a phrenic nerve and leading to diaphragmatic paralysis
Pain and nerve entrapment Pleural pain may indicate malignant pleural invasion, although it
can occur with distal infection. Intercostal nerve invovement causes pain in the distribution of a
thoracic dermatome.
Cancer in the lung apex may cause Homer's syndrome (ipsilatera partial ptoss, enophthalmos
miosis and hypohidrosis of the face due to involvement of the sympathetic nerves to the eye at or
above the stellate
12. Mediastinal spread: Involvement of the oesophagus may cause dysphagia.
if the pericardium is invaded, anhythmia or pericardia effusion may occur.
Superior vena cava obstruction by malignant nodes causes suffusion and swelling
of the neck and face.
Involvement of the left recurrent laryngeal nerve by tumours at the left hilum
causes vocal cord paralysis, voice ateration .
Metastatic spread This may lead to focal neurological defects. epileptic seizures,
personality change, jaundice, bone pain or skin nodulos. Lassitudo, anorexia and
weight loss usually indicato metastatic spread.
13. Finger clubbing Overgrowth of the soft tissue of the terminal phalanx,
leading to increased nail curvature and nail bed fluctuation, is often
seen.
Hypertrophic pulmonary osteoarthropathy (HPOA) This is a pantul
periostitis of the distal tibia, fibula, radius and ulna, with local
tendemess .
14.
15. Investigations
The main aims of investigation are to confirm the diagnosis, establish the
histological cell type and define the extent of the disease.
Imaging
Lung cancer produces a range of appearances on chest X-ray, from lobar
collapse to mass lesions, effusion or malignant rib destruction.
CT should be performed early, as it may reveal mediastinal or metastatic spread
and is helpful for planning biopsy procedures.
Biopsy and histopathology
Over half of primary lung tumours can be visualised and sampled directly by
biopsy and brushing using a flexible bronchoscope. Bronchoscopy also allows
an assessment of operability, from the proximity of central tumours to the main
carina.
16.
17. Management
Surgical treatment
Accurate pre-operative staging, coupled with improvements in
surgical and post-operative care, now offers 5-year survival rates
of over 75% in stage I disease (N0, tumour confined within visceral
pleura) and 55% in stage II disease, which includes resection in
patients with ipsilateral peribronchial or hilar node involvement.
18. Radiotherapy is much less effective than surgery, radical radiotherapy
can
Radical radiotherapy is usually combined with chemotherapy when
lymph nodes are involved (stage III). Highly targeted (stereotactic)
radiotherapy may be given in 3–5 treatments for small lesions.
19. The greatest value of radiotherapy, however, is in the palliation
of distressing complications, such as superior vena cava
obstruction, recurrent haemoptysis, and pain caused by chest
wall invasion or by skeletal metastatic deposits. Obstruction of
the trachea and main bronchi can also be relieved temporary.
21. Laser therapy and stenting
Palliation of symptoms caused by major airway obstruction can be
achieved in selected patients using bronchoscopic laser treatment to
clear tumour tissue and allow re-aeration of collapsed lung.
The best results are achieved in tumours of the main bronchi.
22. Secondary tumours of the lung
Blood-borne metastatic deposits in the lungs may be derived from
many primary carcinomas, in particular breast, kidney, uterus, ovary,
testes and thyroid, and also from osteogenic and other sarcomas.
These secondary deposits are usually multiple and bilateral.
Often there are no respiratory symptoms and the diagnosis is
incidental on X-ray.
Breathlessness may occur if a considerable amount of lung tissue has
been replaced by metastatic tumour.
23. Endobronchial deposits are uncommon but can cause haemoptysis
and lobar collapse.
The chest X-ray shows diffuse pulmonary shadowing radiating from
the hilar regions, often with septal lines, and CT shows characteristic
polygonal thickened interlobular septa.
Palliation of breathlessness with opiates may help.
27. Benign tumours and cysts in the mediastinum are often diagnosed when
a chest X-ray is undertaken for some other reason.
In general, they do not invade vital structures but may cause symptoms
by compressing the trachea or the superior vena cava.
A dermoid cyst may very occasionally rupture into a bronchus.
Malignant mediastinal tumours are distinguished by their power to
invade, as well as compress, surrounding structures.
28. Investigations
A benign mediastinal tumour generally appears on chest X-ray as a
sharply circumscribed mediastinal opacity encroaching on one or both
lung fields.
CT (or MRI) is the investigation of choice for mediastinal tumours .
A malignant mediastinal tumour seldom has a clearly defined margin
and often presents as a general broadening of the mediastinum. •
Bronchoscopy may reveal a primary lung cancer causing mediastinal
lymphadenopathy.
29. The posterior mediastinum can be imaged and biopsied via the
oesophagus using endoscopic ultrasound.
Mediastinoscopy under general anaesthetic can be used to visualise
and biopsy masses in the superior and anterior mediastinum but
surgical exploration of the chest, with removal of part or all of the
tumour, is often required to obtain a histological diagnosis.
30. Management
Benign mediastinal tumours should be removed surgically because most
produce symptoms sooner or later.
Cysts may become infected, while neural tumours have the potential to
undergo malignant transformation.
The operative mortality is low in the absence of coexisting
cardiovascular disease or COPD
