The lungs are a pair of organs positioned in the thorax that form part of the respiratory system together with the nose, pharynx, larynx, trachea, bronchi, bronchioles and alveoli and the diaphragm.

The main function of the respiratory system is the gaseous exchange, capturing oxygen that will be sent to the different organs of the body, and expelling carbon dioxide product of cellular activity.

Abnormalities in any part of the system cause this gas exchange to be less efficient, which in turn has a series of negative implications throughout the body.

In the case of the lungs, these problems and abnormalities can be caused by a number of diseases, among the most common of which are asthma, partial collapse of the lung (pneumothorax), COPD (chronic obstructive pulmonary disease), pneumonia, pulmonary edema, bronchitis, pulmonary embolism and lung cancer.


What is lung cancer?

Lung cancer is characterized by the uncontrolled spread of lung cells to form tumors. This cancer is especially relevant as it is the most prevalent cancer worldwide, as well as the cause of most deaths by cancer.


 What types of lung cancer are there?

There are currently two types of lung cancer: small cell lung cancer (microcytic) and non-small cell lung cancer (non-small cell).

1- Small cell lung cancer (SCLC): This cancer is responsible for approximately 10%-15% of lung cancers. It is much faster acting and more aggressive. It tends to occur in primary and secondary bronchi.

This type of cancer can be classified as follows:

On the one hand, by the the stage of the tumor, recognizing two stages: limited stage, in which the cancer is found only in one of the lungs or at most has migrated to the supraclavicular nodes, and advanced stage, in which this cancer has already spread to the other lung, nodes or to other parts of the body.

On the other hand, the TNM classification system is also used. These acronyms come from 3 informative keys of the tumor:

  • Tumor size and extent.
  • The spread to lymph nodes and adjacent nodes.
  • Metastasis to more distant sites.

2- Non-small cell lung cancer (NSCLC): Responsible for 85%-90% of lung cancers. It creates generally slower growing and less aggressive tumors.

They also follow the TNM staging system and can also be staged. In this case, the stages range from I to IV, with stage I being the least aggressive and the least spreading and stage IV being the most aggressive.


What are the symptoms?

In many occasions, lung cancer does not show symptoms until very advanced stages and sometimes these symptoms can take time to be associated with the disease, this is what makes this kind of cancer so deadly.

The most common symptoms are:

  • Cough that does not go away in 2-3 weeks.
  • Long cough that gets worse.
  • Recurrent chest infections.
  • Coughing up blood.
  • Pain when breathing or coughing.
  • Persistent shortness of breath.
  • Tiredness and lack of energy.
  • Unexplained loss of appetite and weight.

Some less common symptoms would be:

  • Changes in the appearance of the fingers, such as increased curvature.
  • Problems and/or pain when swallowing.
  • Wheezing from the chest.
  • Hoarse voice.
  • Swelling of the face or neck.
  • Persistent chest or shoulder pain.


How is it diagnosed?

Lung cancer can sometimes be detected early by testing patients who are prone to lung cancer. Unfortunately, most of the time the cancer is detected after the onset of symptoms.

If you have symptoms of possible lung cancer, your doctor will first ask you about your family history and medical history, as well as health habits such as whether or not you are a smoker.

In addition to this, your doctor will perform different physical and imaging tests to rule out cancer.

  • Blood and urine tests to know the patient’s general health status. This may detect liver or kidney problems.
  • Chest X-ray in the search for “spots” or nodules in the lung, changes in the mediastinum, or pleural effusions (accumulation of fluid in the pleura), since they are indicators of the disease.
  • In sputum cytology, the patient’s sputum cells are analyzed under a microscope.
  • Bronchoscopy or fibrobronchoscopy to analyze the trachea and bronchi from the inside, a small flexible tube with a camera and a mechanism to take samples of the suspicious parts (biopsies) is introduced there. This technique allows to detect the size and position of the tumor if there is one. It is a little more aggressive and uncomfortable for the patient and requires anesthesia.
  • Biopsies: There are different types of lung biopsies, but the purpose of all of them is to extract a sample of the possible damaged area for subsequent study in the laboratory
  • Scanning or CT (Computerized Tomography) is a painless procedure that takes about 20-30 minutes and consists of taking images of the patient’s anatomy. There are three types. Thoracic CT to see the lungs, Cranial CT to see if there is metastasis in the brain and Abdominal CT to detect if there is expansion in other organs such as the kidney or the liver. 
  • Bone scintigraphy is a technique to see if there are bone metastases. A radioactive substance (isotope) is introduced which has a greater affinity for the tumor cells, so that, in the event of metastasis, these areas will appear much darker in the image.
  • Positron Emission Tomography (PET) is used to detect non-visible lesions. For this purpose a slightly radioactive sugar (known as FDG) is introduced into the blood, which, as in the bone scan, has an affinity for tumor cells, so that the areas with this type of cell will also appear darker.

On many occasions CT and PET techniques are used in consonance in order to be able to see more precisely where the tumors are or even, in the case of being in a treatment stage, to know more precisely how they are evolving.

In addition to these techniques, studies are currently being carried out to be able to detect lung cancer more accurately and/or earlier.

For our part, Life Length has been investigating the relationship between telomeres, telomerase and various cancers for years. Abnormal telomerase activity has been pointed out on many occasions as one of the main triggers of cancer. Likewise, individuals with shorter telomeres are also more likely to develop cancer.

Life Length is currently developing a lung cancer screening test through an intravenous blood sample that will potentially save complications and discomfort for the patient, as well as enhance early detection of lung cancer.


What treatments are available?

The type of treatment used to try to cure lung cancer will be determined by different factors such as the type of cancer, the stage of the cancer, whether or not there are metastases….

In localized cancers, in early stages and when the person is in good health, the first option is usually surgery, that is to say, to remove the area where the tumor is located. Whether or not surgery is performed will depend on the size of the tumor and the patient’s state of health.

In many cases, radiotherapy is also used in the early stage, administering high-energy x-rays to destroy the cancerous cells. Radiation therapy is used to shrink the tumor prior to surgery, to eliminate cancer cells that may remain after surgery and to palliate the symptoms of lung cancer that has metastasized to other parts of the body,

Pre- and post-surgery, chemotherapy is also often administered, i.e. drugs that are toxic to cancer cells are injected intravenously, slowing down the disease. This treatment is actually used in all stages of cancer, and in patients who cannot be operated on, it often minimizes symptoms of the disease itself.

These techniques are used in conjunction with each other, but in the case of small cell lung cancer, surgery often cannot be considered, as the tumors are usually much more aggressive and faster. This is why chemotherapy and radiotherapy are usually combined. In the case of radiotherapy, prophylactic cranial irradiation may sometimes be recommended, that is, preventive irradiation of the brain to avoid metastases in this organ.

In non-small cell lung cancer, as it grows more slowly, it takes longer to spread outside the lung. In these cases, surgery and radiotherapy are widely used and the use of chemotherapy is reserved to increase the effectiveness of surgery or radiotherapy, being a different chemotherapy to that provided in SCLC cancer.


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