Lung Cancer – Risk Factors, Symptoms And Diagnosis
Lung cancer consists in developing of malignant tumors in the lungs, with a starting point in bronchial and lung structures. Worldwide, lung cancer is the first cause of mortality, ranking first place among cancers which can occur in men and third among cancers in women. Lung cancer incidence is increasing in proportion to the frequency of smoking and air pollution, age of maximum incidence is between 45 and 60.
Lung Cancer Risk Factors
The most important risk factors for lung cancer development are carcinogenic factors, genetic factors and dietary factors.
- Chemical carcinogens are smoking, air pollution and occupational pollution.
- Smoking is the most important factor, is responsible for 85% of lung cancers. In pulmonary cancer counts the number of cigarettes smoked per day, length in years of this habit, the onset of smoking at young ages, the presence of cigarette filter. A less important role it has smoke.
- Air pollution occurs with certain substances detected in the air, especially in urban areas, which are identical to those found in cigarette smoke (benzopiren). In industrialized regions, the rate of death by lung cancer is 2-5 times higher than in rural areas.
- Professional pollution it increases the frequency of lung cancer, especially if is associated with smoking. Occupational hazards are responsible for developing pulmonary cancer, like asbestos, iron oxides, arsenic (from pesticides, glass industry), tar, chromium and nickel.As these factors are very diverse you should check out the specific chemical hazard that relates to you; for example, if you work in the insulation industry you might be interested mesothelioma related articles.
- Radioactive carcinogens are represented uranium and polonium.
2. Genetic factor lies in genetic susceptibility to the environmental factors involved in the development of lung cancer based on aggregation of cases in some families.
3. Food factor. Recent studies confirm an inverse relationship between cancer and consumption of fruits and vegetables, and the existence of protective substances, like antioxidants (vitamins A, C, E and selenium).
Lung cancer is polymorphic and heterogeneous, and in terms of pathology can be:
- Epidermoid carcinoma (squamous cell) has a frequency of approximately 29% and often is located in the large bronchi. Metastasize late and therefor is operable and with the best prognosis. Is less sensitive to chemotherapy and radiotherapy.
- Small cell carcinoma has a frequency about 18%, is usually located in the large bronchi. Metastasize early, diffuse and varied, being considered the most aggressive form of cancer. Usually, it is considered that at the time of diagnosis, cancer reached the systemic dissemination stage and, therefore, is inoperable.
- Adenocarcinoma has a frequency of about 32%, more frequently located peripherally. Has a severe evolution, because of early metastasis and is less sensitive to chemotherapy and radiotherapy.
- Large cell carcinoma has a frequency of about 9%, is located peripherally. Usually, is presented like a large mass, over 10 cm.
From the clinical, prognostic and therapeutically point of view is useful the classification of pulmonary cancer in:
- Small cell carcinoma, aggressive, with poor prognosis receiving chemotherapy;
- Non small cell carcinoma, including the rest of types which were described, with something better prognosis and which are treated with surgery, chemotherapy and radiotherapy according to the stage in which the cancer is discovered.
Lung Cancer Symptoms And Clinical Diagnosis
Currently lung cancer diagnosis is established late, which contributes decisively to the bad results of therapy. Early diagnosis of pulmonary cancer is currently the only way to improve the prognosis of this disease.
Signs of the respiratory function:
- Cough is the symptom most consistently and most important for diagnosis, if the patient is paying attention since the first weeks after appearance and after changing its character. Coughing can occur in a smoker patient but also in nonsmokers and has the following characters: persistent, dry, irritating nature, rebellious to treatment with antitussives. If the patient is chronically coughing, lung cancer diagnosis may be suggested by: changing of tonality, the increase in intensity, in duration, declined answer to antitussives drugs. Any old cough that gets worse should be suspected as caused by lung cancer;
- Hemoptysis (coughing blood) can be of variable intensity;
- Dyspnea is caused by compression or obstruction of the trachea and of the large bronchi;
- Chest pain occurs in late stages of pulmonary cancer;
- Infectious episodes (pneumonia, lung abscess).
Signs of locally extension:
- Superior Vena Cava compression syndrome, characterized by dizziness, headache, swelling in pelerine;
- Claude Bernard Horner syndrome, characterized by enoftalmie, miosis, reduction of palpebral fissure;
- Pleurisy by invasion of the pleura;
- Heart rhythm disturbances that reflect the extension of tumor in pericardium and heart.
Signs given by metastases:
Metastatic potential of lung cancer is increased, about 60% – 70% of patients having metastases at presentation to the doctor. The most common organs in which metastasize lung cancer are: bone, brain, adrenal glands, bone marrow, lymph nodes.
Paraneoplastic syndromes, induced by the secretion of hormones and peptides by the tumor, are manifested through signs which appear at distance from neoplasia, they may precede by months to years the tumor manifestations, disappear after treatment and occur in case of relapse. These are:
- Bone: digital clubbing, painful and swollen joints;
- Nervous system: sensory-motor neuropathy, cerebellar syndrome;
- In muscle: polymyositis and dermatomyositis;
- Endocrine: gynecomastia, hyperthyroidism, Cushing’s syndrome;
- Vascular and hematologic: migratory thrombophlebitis, anemia, thrombocythemia, thrombocytopenia;
- Skin: acanthosis nigricans;
- Renal: Nephrotic syndrome;
- Metabolic: lactic acidosis, hyperuricemia.
General symptoms, include fever, weight loss, fatigue, anorexia, aversion to tobacco in smokers.
Lung Cancer Diagnosis
- Chest radiography is fundamental, but unfortunately, many times, when lung cancer is evident radiographically, the diagnosis is delayed.
- CT scan is useful for determining the nature of a chest mass, based on tomographic density, highlighting the mediastinal lymph damage, emphasizing the extension of lung cancer in the mediastinum, pleura and ribs. Abdominal sections will be done for the examination of the liver and adrenal glands.
- Bronchoscopy is a important paramount because it allows the biopsy of the tumors and assessment of tumor extension.
- Cytological examination of sputum may show the existence of tumor cells.
- Laboratory tests, provide little information such as acceleration of ESR, serum calcium, serum sodium levels, potassium levels can be changed. Tumor markers are of a limited importance, because they are not specific.
- Functional respiratory exploration (spirometry) indicates whether surgery is possible or not.
- Other paraclinical: brain CT, scintigraphy, bone MRI, marrow biopsy, abdominal ultrasound to detect metastases.
Lung cancer prognosis is restricted because of late diagnosis, but also because of the early metastasis of this type of cancer. With complete treatment, life expectancy at 5 years, in patient with lung cancer is 10%.