Lung cancer

Lung cancerThe main players in lung cancer development are harmful environmental influences with smoking being the number one (90% of this disease cases is linked to smoking). Lung cancer is the leading cause of death among all cancers. According to the World Health Organization (WHO) estimates, lung cancer is responsible for 5% of deaths annually. There are different forms of lung cancer, differentiated according to the cancer cell sizes. The outcome of the disease depends on the cell type and cancer stage. Lung cancer presents with various signs and symptoms, the most common ones being cough, dyspnoea and unexplained loss of weight.

Why should you have your DNA analysed for predisposition to lung cancer?

By checking your genome we can discover variants of your genes which play key roles in protecting your lungs from cancer development.

How is lung cancer prevented or treated?

The development of lung cancer can be prevented with smoking cessation and avoiding smoking areas. You are especially advised to do so if you are susceptible to this disease. Lung cancer is treated with surgical tumour resection, radiation therapy and chemotherapy.

More detailed description about lung cancer

As in all cancer types, the dominant feature of lung cancer is the malignant transformation of the cell which is the basic building block of life. The malignant cell displays uncontrolled divisions, invasion into the neighbouring tissue and the capability of blood or lymphatic seeding of other organs where it further multiplies. Such tumour tissue displaces normal tissue, causes blocks in the hollow organs as well as bleeding, and deprives the entire organism of nutrition. In addition, tumour tissue often releases toxic and hormonally active substances and triggers immune reactions which may affect other organs as well.

Causes for lung cancer development

There are many risk factors leading to the development of lung cancer, but cigarette smoking is an absolute number one. 90% of all lung cancers are associated with smoking. The risk increases with the number of packs smoked per day. A smoker who smokes one pack a day runs a 25-fold increase in risk for cancer development compared to a non-smoker. The cigarette smoke contains over 4,000 substances, among them substances that induce the development of cancer, the so called carcinogenic substances. Besides active smoking, passive smoking is also a risk factor. Passive smoking means that a person does not smoke himself/herself, but rather inhales the cigarette smoke of the smokers in his/her vicinity.

The risk factors further include some other toxic substances in the air that we breathe, such as for instances asbestos fibres. Asbestos is a material which had long been used for heating and sound insulation of houses. Those who got sick were mainly the workers in the asbestos industry. The remaining risk factors include the exposure to the radioactive radon gas (which can ooze out of the poor-quality construction material of some houses), other pulmonary diseases in the patient's past medical history and the general environmental air pollution.

Lung cancer types

Several types of lung cancer are known. The subdivision is important in order to evaluate the cancer spread, the disease prognosis and therapy. The subtypes include the small cell carcinoma, squamous cell carcinoma (because it develops from the squamous epithelial cells) and adenocarcinoma (developing from glandular cells). Small cell carcinoma is characterized by a very fast growth rate and fast spread to other organs of the human body, forming the so called metastases. This cancer type is to 99% connected with cigarette smoking. Both the small cell carcinoma as well as the squamous cell carcinoma usually form in areas where the bronchi enter the pulmonary tissue, while adenocarcinoma mostly grows peripherally. Adenocarcinoma is the type that is least associated with smoking.

Lung cancer can present with various signs and symptoms, most commonly cough, dyspnoea (difficulty breathing) and unexplained weight loss. Less commonly, there is chest pain, fever, weakness and blood in the sputum.

Disease diagnosis

In order to diagnose lung cancer, a thorough physical exam must initially be performed and a detailed patient history taken. It must be checked for enlarged cervical and axial lymph nodes. Furthermore, a chest x-ray and a chest CT (computer tomography) can aid the physician in making the diagnosis. Bronchoscopy, however, is the golden standard in lung cancer diagnostics. The physician uses a special device, a bronchoscope, to inspect the airways. The bronchoscope enables a concomitant removal of a lung tissue biopsy sample which is used to determine lung cancer grade and stage.

Prevention

The most convincing factor that plays a role in the development of lung cancer is undoubtedly smoking. The risk of a smoker to get lung cancer increases proportionally with the earlier the age at which the smoking began, the longer the smoking period and the greater the number of cigarettes smoked. This is important information for those who have never smoked to never actually start smoking as well as for the smokers to stop smoking. As is the case with any addiction, it is hard to stop smoking. It is recommended that you consult your physician about potential smoking cessation programs that are administered in your region as well as about the use of nicotine substitutions such as patches or chewing gums; they can be of help, but by itself they are not sufficient.

An antidepressant bupropion has lately been in use as well; it alleviates the withdrawal symptoms. The country's measures are also very important such as the price and tax regulations, protection against tobacco smoke, education and raising awareness of the public, advertising bans, the requirement of putting the warning signs on cigarette packs, etc.

The preventive measures against lung cancer also include avoidance of cancerogens (such as asbestos, aromatic hydrocarbons, arsenic, cadmium, beryllium, etc.) in the workplace; it is regulated by the Health and Safety at Work Act which specifies the duties of the employer (provision of information, offering the option of protection masks, educational programs, etc.) as well as the duties of the employee (the actual use of the protective equipment, required medical check-ups, etc).

Therapy

It is essential that lung cancer therapy be tailored according to the individual patient's needs. Patients vary in age, cancer type, cancer grade and stage, lung function, the presence of comorbidities, general psycho-physical condition and, last but not least, patient motivation for treatment for the role of the patient is essential in any treatment.

Lung cancer may be treated in various ways:

Surgical therapy - if at all possible, cancer should be surgically removed. This can be accomplished by the removal of a lung lobe or the entire lung wing. If metastases are present, tumours can still be surgically removed with the aim of alleviating problems associated with the pressure exerted by the tumour on the adjacent structures.
Radiotherapy may be radical or palliative. The aim of the radical radiotherapy is to destroy the cancer cell mass using ionizing radiation. However, since this radiation destroys healthy cells as well, it is very important to determine the exact tumour location and size in order to minimize damage caused by irradiating healthy tissues. Palliative radiotherapy is used with the aim of reducing the tumour volume and alleviating the problems.
Systemic chemotherapy with cytotoxic substances, i.e. substances that kill rapidly dividing cells (rapid division is the main characteristic of cancer cells). Cancer treatment is carried out in cycles or continuously. The type of the most suitable chemotherapy depends on the cancer type. Biological drugs provide new hope for they act by binding specifically and exclusively to cancer cells.

Palliative therapy - the aim of this treatment is to positively affect the quality of patient's life by using measures to maintain and improve the lung function by performing breathing exercises, teaching the patient the right expectoration technique and breathing techniques that alleviate symptoms in the advanced phase of disease. In addition, measures to improve and maintain the nutritional state of the patients by employing a high protein/high fat diet in case of weight loss are needed. Furthermore, smoking cessation is encouraged and prophylactic anti-thrombotic (i.e. against blood clot formation) therapy instituted.