Lung Cancer: The price of smoking

Cells are the smallest units of life in the human body. One of their functions is to reproduce and die when they are no longer useful. This process is orderly, in time and space, so that there is always the right number of cells for each stage of life.

Lung cancer consists of an abnormal growth of the cells of the lung, units with major defects and dysfunctions, which reproduce aberrantly and alter the state of delicate surrounding structures.

 The disease occurs in the internal walls of the bronchi and, as it grows, it can obstruct the passage of air and alter breathing. It usually causes shortness of breath, choking, and fatigue.

However, despite its high mortality rate, we now know it is one of the most preventable cancers thanks to several studies linking it to tobacco use, so not smoking or quitting smoking is the best possible prevention.


The main cause is exposure to tobacco smoke through inhalation of carcinogenic substances it contains. The 90% of lung cancer cases occur in smokers because cigarettes increase up to 30 times the chances of developing a lung carcinoma and among passive smokers, the risk of developing it is almost twice that of an unexposed person.

The number of cigarettes smoked and the years of consumption also have a decisive influence on the risk of suffering from this cancer; the greater the number of cigarettes smoked and the more years of smoking, the greater the risk and the danger will decrease with the smoking cessation.

Nicotine enhances the carcinogenic effect of other substances from tobacco smoke and the effects of carcinogens on the environment. Nicotine acts on the mechanism of apoptosis, or cell death, preventing cells from committing suicide. With cancer cells, it does the same thing, causing or stimulating the cancer formation.

Other genetic or environmental causes such as the inhalation of asbestos, aromatic hydrocarbons and suffering from other lung diseases such as COPD or pulmonary fibrosis, can also be the origin of lung cancer but their incidence is lower


The type of cell that produces the tumor classifies lung cancer. The 90% of them are small cell or non-small cell. The remaining 10% are very infrequent classes, such as mixed, carcinoids or neuroendocrine tumors.


Small Cell Lung Cancer (Microcytic)

Experts refer to it that way because of the size of the cells seen under a microscope. They relate it to smoking and estimate that about 20% of all cancers are small cell cancers. They multiply rapidly and large tumors can form, and their ability to spread to other organs is greater. The small cell neoplasm is usually a very aggressive type of cancer.

The primary tumor originates near the bronchi and spreads to the center of the lungs, and metastases (spread) usually affect the following organs: lymph nodes, bones, brain, adrenal glands, and liver. 

Non-Small Cell Lung Cancer

This type of cancer accounts for almost 80% of all lung cancers. It spreads more slowly than small cell lung cancer and may occasionally appear in non-smokers.

There are some varieties of non-microcytic lung cancer. The two most common are squamous or epidermoid carcinoma and adenocarcinoma. The first is the most common and like the microcytic, is usually born from the depth of the lung, in the center of the chest. Adenocarcinoma is rarer and is usually the kind of lung tumor that non-smokers have. It arises from the most peripheral parts of the lung, near the chest wall.

Symptoms of Lung Cancer

The main symptom is a persistent cough with or without expectoration. It occurs in 3 out of 4 patients but is not a specific symptom of lung cancer, tobacco itself produces bronchial irritation with respiratory symptoms that can lead a smoker diagnosed with acute bronchitis or chronic obstructive pulmonary disease to minimize the aggravation of his syndrome. Other symptoms may include:

  • Hemoptysis (coughing up blood)
  • Dyspnea (shortness of breath)
  • Wheezing (whistling in the chest)
  • Dysphonia (voice changes)
  • Chest pain and pain when breathing in 

Besides these respiratory symptoms, advanced lung cancer produces a series of signs common to any cancer that affect the general state: weight loss, lack of appetite, general fatigue, low defenses, and fever.

If the cancer has spread to other organs at a distance (metastasis), other local symptoms may appear depending on the affected area. The affected target organs are the brain, liver, adrenal glands and bones, manifested in headaches, vomiting, convulsions, neurological deficits, extreme weakness, and bone pain.



Depending on the histological type and the TNM stage in which experts find the tumor, the treatment will be aggressive and may be a candidate for surgical removal of the tumor mass, chemotherapy or radiation therapy.

In the early stages, when the tumor has not spread, surgical resection may range from removal of the affected lung lobe to resection of the entire lung and the prognosis in these instances is very good. In case of lymph node invasion or distant metastasis, surgery is not useful and treatment consists of combinations of chemotherapy and radiotherapy.

As the risk of recurrence of lung cancer is high, even though it has resected up (it reappears in a high percentage of patients), they may administer chemotherapy after surgery to prevent recurrences and improve prognosis.

For microcytic carcinoma, chemotherapy is the first choice.


In lung cancer, life expectancy is low, although overall survival is increasing: according to EUROCARE-4 data, 10.7% of lung cancer patients survive for 5 years; even evolution and prognosis depend on different factors. These can be:

  • Type: Microcytic or non-small cell.
  • Stage: According to TNM classification.
  • Location: Region in the lung.
  • The patient’s overall health, age, and sex (since women have a better prognosis).

In lung cancer, the highest life expectancy and chances of survival occur in the early stages. However, life expectancy decreases as the cancer progresses.

In microcytic lung cancer, the prognosis is unfavorable. In this tumor, the chances of survival are low and the average life expectancy varies between three and five months. However, there is also a chance of recovery. In about 5% of cases, the tumor disappears after chemotherapy and radiotherapy.