Carlos R. Salvarezza
It is the tumor that causes the highest number of deaths in males. Its incidence increased considerably in the last 40 years.
Generally it originates in bronchial segments and subsegments, being the epithelium of the bifurcation of the segments the most sensitive area to the deposit of carcinogens.
The immediate response to the gression of the etiological agents is the proliferation of basal cells that generate mucin, later the columnar cells are replaced by stratified squamous epithelium, which is later disorganized, causing mitosis and nuclear atypia. At this stage there is an intraepithelial carichinoma with an undamaged basement membrane, called carcino in situ. Evolutionarily, the basement membrane is invaded by neoplastic cells that infiltrate the underlying tissues.
This hispathological process, from its beginning until the tumor measures 10 mm in diameter, lasts from 10 to 20 years.
I smoke. Statistical studies and innumerable investigations established the relationship between lung cancer and smoking. The following evidences are confirmatory: the finding of benzopyrene and other carcinogens in the combustion of tobacco, the observation of histological changes in the epithelium of heavy smokers (including precarcinomatous alterations), the increased incidence of other diseases associated with smoking in patients with cancer. pulmonary, the experimental production of tumors in animals by applying tobacco to the skin and other organs.
Hereditary and racial factors . They are difficult to evaluate in human pathology. All the evidence tends to show that environmental factors are more important.
Chronic inflammations. Scarring . Chronic bronchitis predisposes to lung cancer, according to the evidence of numerous works. There are tumors called tumorlet because of their appearance and function that only settle in previously damaged lung tissue.
Occupational causes . Radiation. The importance of radioactive gas in certain mines is supported by studies that found that 70% of Schneeberg miners died of lung cancer.
Arsenic: the content of arsenic in the bronchial mucosa and submucosa was higher in patients with lung cancer than in control groups.
Nickel . It would indirectly cause cancer by chemical damage to lung tissue.
Asbestos . The carcinogenic properties of asbestos are attributed to traces of benzopyrene and polycyclic hydrocarbons. Orocidolite is the most dangerous abest fiber.
Chromates, beryllium, carbon gas and others . They are also related to bronchogenic carcinomas.
Air pollution. The increased incidence of lung cancer coincided with a period of great industrial expansion and the introduction of the automobile. These factors considerably increased pollution. Carcinogens include 3-4 benzopyrene, 1-12 benzoperylene, traces of radioactive substances, oil vapor, arsenic. These substances reach very high levels during periods of fog (smog).
Symptoms and signs
Interrogation . The manifestations depend on the local growth of the tumor, the invasion of neighboring structures, the presence of lymph node metastasis or visceral metastasis, and paraneoplastic syndromes.
The suspicion of a bronchogenic carcinoma is based on a patient over 40 years old, a smoker, preferably male, who presents one or more of the following symptoms:
Cough . The one that lasts more than 30 days without responding to the usual medication, or a change in the usual characteristics of a chronic coughing.
Expectoration . It is nonspecific, and can be mucous, mucopurulent, or purulent
Hemoptysis . It is valuable when it is presented in the form of hemoptoic sputum. This symptom is alarming for the patient and makes him quickly consult the doctor.
Chest pain . Of indefinite characteristics, generally the product of pleural, middiastinal or thoracic wall invasion.
Breathlessness . associated with pleural effusion, atelectasis, pneumonia, mediastinal invasion. Occasionally of reflex cause.
General syndromes . Usually produced by distant metastases. Hyporexia, weight loss, decay, fever.
Mediastinal syndromes . Intrathoracic spread of the tumor by direct invasion or by lymphatic metastasis compresses or infiltrates the organs housed in the mediastinum and causes venous, nervous, lymphatic, upper digestive and lower airway syndromes.
Paraneoplastic syndromes. They are general conditions located outside the thorax, not related to metastasis and dependent on the primitive tumor. The most frequent are: a) skeletal: drumstick fingers, hypertrophy pneumatic osteoarthropathy; b) endocrine: inappropriate secretion of antidiuretic hormone (hyponatremia), ectopic secretion of parathyroid hormone (hypercalcemine), ectopic secretion of ACTH (cushing); c) neuromuscular: myastheniform syndromes, peripheral neuropathy, acute cerebellar degeneration, cortical degeneration, polymyositis; d) haematics: anemia, agranulocytosis, leukoerythroblastosis; e) vascular: migratory thrombophlebitis, non-bacterial thrombotic endocarditis; f) cutaneous: palmoplantar hyperkeratosis, iscytosis, acanthosis ingricans, dermatomyositis; g) renal: nephrotic syndrome and glomerulonephritis.
Physical exam . It is positive when the tumor obstructs bronchi (pneumonia, atelectasis, abscess) or invades the pleura (liquid effusion) or the mediastinum (mediastinal syndrome).
Radiographic examinations . Chest X-ray. Generally, abnormalities are detected in the radiographic pair: unilateral hilar enlargement, single nodule (diameter up to 4 cm), mass (diameter greater than 4 cm), infiltrate of hymogeneic density or not, consolidation, atelectasis, cavitation, enlarged mediastinum, pleural fluid effusion .
Linear tomography . Indicated to confirm or rule out questionable images.
Computed axial tomography . It is used in the case of suspected lesions, the degree of precision is much higher than that of linear tomography.
Laboratory . Hemogram . It may be normal to show anemia.
Erythrosedimentation : generally accelerated.
Serum mucoproteins . You are usually increased.
Sputum cytology . The serial examination of the expectoration looking for neoplastic cells is very useful: the positivity ranges between 70 and 90%
Fiberoptic bronchoscopy . It is the most used method in the diagnosis of bronchogenic carcinoma. The combination of brushing and bronchial biopsy yields a positivity that varies between 75 and 85%.
Pneumocentesis . It is the puncture and aspiration of the lung through the thoracic walls. In malignant nodules, positivity is greater than 90%.
Exploratory thoracotomy and lung biopsy . It is used when the methods described above do not allow the diagnosis of bronchogenic carcinoma.