Generality
Lung adenocarcinoma, or adenocarcinoma of the lung, is the most common lung cancer in humans, be it a smoker or a non-smoker.
The most important risk factors for pulmonary adenocarcinoma are cigarette smoking, passive smoking and prolonged exposure to radon gas.
The typical symptoms consist of: intense cough, cough with blood emission, chest pain, dyspnea, presence of blood in the sputum, fever, asthenia and chest pain.
Possible treatments for pulmonary adenocarcinoma include surgery, radiotherapy and chemotherapy.
What is an adenocarcinoma
An adenocarcinoma is a type of carcinoma - hence a malignant tumor - that originates from epithelial cells of the exocrine glandular organs or from epithelial cells of tissues with secretory properties .
Examples of exocrine glandular organs are breast, pancreas or prostate; examples of tissues with secretory properties, on the other hand, are the layers of mucosa that line the inner wall of the airways, esophagus, stomach, colon or rectum.
What is pulmonary adenocarcinoma
Lung adenocarcinoma, or adenocarcinoma of the lung, is a malignant lung tumor that originates from the epithelial cells of the mucosal layers present in the lung.
Among the primary forms of lung cancer, pulmonary adenocarcinoma has the sad distinction of being the most common.
PRECISE SITE OF ORIGIN
The precise place of origin of the pulmonary adenocarcinomas is at the level of the peripheral epithelial tissues of the lung ; these tissues include the cells of the bronchial tree (terminal tract) secreting mucus and the cells of the pulmonary acini .
What are the bronchial tree and the pulmonary acini?
The bronchial tree is a fundamental trait of the lower airways and includes the respiratory structures known as bronchi and bronchioles. Above, it follows the trachea and, with its terminal portion, re-enters the structure of the lungs.
A pulmonary berry is a collection of pulmonary alveoli, ie those small pockets of the lungs within which gas exchange takes place between the blood and the inspired atmospheric air.
The pulmonary acini reside at the ends of the pulmonary bronchioles.
CLASSIFICATION OF PULMONARY ADENOCARCINOMA
The extreme histological heterogeneity, which characterizes pulmonary adenocarcinoma, has led doctors and pathologists to distinguish the aforementioned malignant tumor in at least two types and different subtypes.
The two types of adenocarcinoma of the lung are:
- Non-invasive or minimally invasive adenocarcinoma, whose subtypes are:
- Adenocarcinoma in situ of the lung (or bronchioalveolar carcinoma)
- Minimally invasive pulmonary adenocarcinoma
- Invasive adenocarcinoma, whose subtypes are:
- The predominantly acinar adenocarcinoma
- The predominantly papillary adenocarcinoma
- Micropapillary predominantly adenocarcinoma
- The solid predominant adenocarcinoma
- The mucinous invasive adenocarcinoma
Causes
Like any tumor, pulmonary adenocarcinoma also arises due to genetic mutations of DNA, mutations that in this specific case affect - as mentioned - the cells of the epithelial tissues of the lungs.
At the molecular-biological level, the aforementioned mutational processes have, as a consequence, the impairment of the cellular processes of growth, division and death: the tumor cells, in fact, grow and divide in an anomalous way, with a rhythm higher than normal, so that, for these reasons, the experts tend to define them with the terminology of " mad cells ".
WHAT DOES THE COMPUTING OF THE MUTATIONS FAVOR?
According to various scientific studies, the main factor favoring the mutations that give rise to pulmonary adenocarcinoma is cigarette smoking .
In fact, for those who smoke, the risk of developing lung cancer is 13 times higher, compared to a non-smoking person.
Other factors favoring, important and worthy of a quote are:
- Exposure to radon . Radon is a radioactive, colorless and odorless gas that forms in the ground.
Exposure to radon represents the second factor favoring all the various types of malignant lung cancer, including pulmonary adenocarcinoma.
For obvious reasons, its combination with cigarette smoking further increases the risk percentages.
- Passive smoking . Tobacco combustion produces fumes containing toxic and carcinogenic substances, which can predispose to various malignant tumors, primarily lung cancer.
- Exposure to asbestos (or asbestos ). Asbestos is a set of minerals (inosilicates and phyllosilicates), arranged in elongated bodies (the so-called "asbestos fibers") and capable of dispersing easily in the air (this involves their inhalation).
Asbestos is the main cause of another type of very aggressive malignant tumor: mesothelioma.
- Exposure to other carcinogens, such as uranium, arsenic, vinyl chloride, nickel chromate, coal combustion products, methyl chlorine ether, etc.
Some details on cigarette smoking and lung cancer:
- The more you smoke, the more likely you are to develop lung cancer.
With regards to this, it is important to point out that the modest old-fashioned smoker is more endangered than the avid smoker who started smoking recently.
- Beginning to smoke at a young age favors the onset of lung cancer, more so than starting in adulthood.
- Quitting smoking reduces the risk of developing lung cancer. The sooner you stop and the greater the health benefits.
Epidemiology
Moreover, it is the most common form of lung cancer in women and, in general, in the whole population under the age of 45.
Symptoms and Complications
Pulmonary adenocarcinoma is a somewhat devious condition, since, very often, the clinical manifestations that characterize its presence appear only at an advanced stage of the disease.
The list of possible symptoms and signs of pulmonary adenocarcinoma includes:
- Intense and persistent cough, with a fairly consistent production of sputum;
- Cough with blood emission (hemoptysis);
- Presence of blood in the sputum (hemoftoe);
- Dyspnea (or shortness of breath) and other breathing difficulties. These disorders also arise due to not particularly intense efforts (eg: walking briskly, making stairs, etc.);
- Chest pain;
- Temperature;
- Asthenia;
- Body weight loss;
- Pain in the shoulder or upper limb, located on the same side of the body as the diseased lung;
- Pneumonia of various kinds;
- Dysphagia;
- Dysphonia.
CAN IT BE ASINTOMATIC?
In a small percentage of cases, pulmonary adenocarcinoma can result in an asymptomatic condition, ie without symptoms and obvious signs.
Experts have calculated that about 6% of people with lung cancer do not show any noteworthy disorder, except when their health is already severely impaired.
COMPLICATIONS
At an advanced stage, pulmonary adenocarcinoma tends to disseminate its cancer cells in other organs and tissues of the body, which are thus contaminated.
The aforementioned process is called metastasis ; the tumor cells that make them protagonists are called metastases .
In the specific case of pulmonary adenocarcinoma, the spread of metastases generally affects the bones, although in some cases it also affects the brain .
From the point of view of symptoms, the involvement of bones by metastases causes bone pain.
WHEN TO REFER TO THE DOCTOR?
It should prompt you to contact your doctor immediately: persistent cough and / or blood, dyspnoea, chest pain and fatigue.
Diagnosis
In general, diagnostic investigations that allow the detection of pulmonary adenocarcinoma begin with an accurate physical examination and a careful medical history (or clinical history).
Then, they continue with some diagnostic imaging tests, including: RX-thorax, thoracic CT, thorax nuclear magnetic resonance (chest MRI) and thoracic PET .
Finally, they end with a lung biopsy .
In some particular circumstances, doctors could prepare further diagnostic tests, such as: sputum analysis, thoracentesis, a brain CT scan to see if there are brain metastases and a bone scan to see if there are bone metastases .
IMPORTANCE OF THE ANAMNESIS
The anamnesis is important because it provides the first indications on the possible factors that have triggered the symptomatology in progress.
For example, the fact that the patient is a heavy smoker or the fact that the patient has come into contact with asbestos is very significant information, from the diagnostic point of view.
RX-CHEST, THORACIC TAC, MRI OF THE CHEST
RX-thorax, thoracic CT and nuclear magnetic resonance of the thorax are three instrumental examinations, each with its own specific functioning, which provide fairly precise images of the lungs and other neighboring organs.
They are useful because they show a certain amount of abnormal cells with a certain degree of clarity.
While the thorax RMN is completely non-invasive, the RX-thorax and thoracic CT scan provide the patient's exposure to a certain dose of harmful ionizing radiation, so they are to be considered minimally invasive.
CHEST PET
The PET of the thorax or of any other anatomical region of the body, provides information related to the functionality of the examined body part.
PULMONARY BIOPSY
Lung biopsy is a minimally invasive diagnostic test, which consists of collecting a sample of lung cells and then analyzing them in the laboratory.
The collection of the lung cell sample can be done in at least 3 different ways: by bronchoscopy ( bronchoscopic biopsy), by aspiration (pulmonary needle biopsy) and by "open sky" surgery ("open-air" lung biopsy).
Lung biopsy is used to accurately delineate the type of lung cancer present and its stage.
What is the stage or staging of a malignant tumor?
The stage, or staging, of a malignant tumor includes all that information, collected during biopsy, which concerns the size of the neoplasm, its infiltrating power and its metastasizing capacities.
Treatment
The treatment of pulmonary adenocarcinoma depends on the stage of the tumor and the general health conditions of the patient.
Generally:
- If pulmonary adenocarcinoma is localized (that is, it has not yet produced metastases), the therapy consists only in surgical removal of the tumor mass.
- If pulmonary adenocarcinoma has scattered some of its cells in other organs and tissues of the body, the treatments involve not only surgery, but also chemotherapy and / or radiotherapy .
DETAILS ON SURGICAL REMOVAL
There are 3 different ways in which a surgeon can perform surgical removal of pulmonary adenocarcinoma:
- Through the so-called " wedge resection ". It is the surgical operation to remove a small portion of the lung. Usually, surgeons resort to it when the tumor mass is small.
- Via lobectomy . It is the surgical removal of one of the lobes that make up the lungs. Usually, surgeons resort to it when the tumor is of medium size.
Remember that the right lung has three lobes, while the left lung has two.
- Via pneumonectomy . It is the total surgical removal of a lung.
Generally, surgeons resort to it when the tumor is very large and has drastically compromised normal lung anatomy.
CHEMOTHERAPY
Chemotherapy consists of the administration of drugs capable of killing all rapidly growing cells, including cancer ones.
Depending on some characteristics of pulmonary adenocarcinoma, the treating physician can decide whether to opt for pre-surgical chemotherapy (also called neoadjuvant chemotherapy ) or for post-surgical chemotherapy (also known as adjuvant chemotherapy ).
According to numerous clinical investigations, the chemotherapy adopted in the case of adenocarcinoma of the lung with metastasis would have the effect of prolonging the life of patients.
RADIOTHERAPY
Radiation therapy involves exposing the tumor mass to a certain dose of high-energy ionizing radiation (X-rays), in order to destroy neoplastic cells.
When radiotherapy treatment takes place before surgery, it is called neoadjuvant radiotherapy ; when, on the other hand, radiotherapy treatment takes place after surgery, it is called adjuvant radiotherapy .
In the case of pulmonary adenocarcinoma, the therapeutic goal of radiotherapy is to reduce the symptoms related to the presence of bone and / or brain metastases.
WHEN YOU CAN NOT APPLY TO SURGERY
When the patient's general health conditions are precarious and a surgical operation could prove fatal, the removal of the tumor by one of the above procedures is contraindicated.
If surgery is contraindicated, chemotherapy and radiotherapy remain the only treatments available to patients.
Often, in these situations, treating doctors opt to associate radiotherapy treatments with chemotherapy ones, in order to obtain better results.
POST-THERAPEUTIC PHASE
At the end of the treatment, a series of periodic checks is planned, aimed at establishing the eradication or not of pulmonary adenocarcinoma.
Post-therapeutic monitoring is important because it allows the attending physician to identify, with a certain timeliness, any tumor recurrences .
Prognosis
The prognosis of pulmonary adenocarcinoma depends on several factors, including:
- The tumor stage
- The general health conditions of the patient
- The position more or less accessible to the surgeon of the tumor mass
In general, also due to the fact that the identification of the tumor mass is often late, the adenocarcinoma of the lung tends to have a negative prognosis.
According to some statistical surveys, less than a fifth of patients with pulmonary adenocarcinoma survive 5 years or more, after the removal and / or the radiochemical treatment of the tumor.
Prevention
Not smoking, avoiding exposure to second-hand smoke, avoiding exposure to radon and avoiding exposure to asbestos are the main preventive measures that doctors recommend to reduce the risk of lung adenocarcinoma.
