What is Lung Cancer?
A healthy human body is programmed to kill these cells at certain stages of the cell cycle in order to prevent the overgrowth and growth of cells. However, mutations may occur in the associated genes of these cells at any stage of the normal cycle program, sometimes due to familial, sometimes environmental, and sometimes nutritional reasons. These mutations accumulate in cells and cause cancer (tumor). In cancerous cells, the control mechanism in healthy cells is ineffective, so cancerous cells multiply and overgrow uncontrollably. Lung cancer is a cancer that starts and develops in the lung tissue or the airways.
Lung Cancer Epidemiology
According to the data of the World Health Organization (WHO), lung cancer is the most common cancer type in the world and the leading cause of death. In 2018, it is estimated that there were close to 2 million new cases and 1.7 million deaths in the world. Lung cancer incidence and mortality rates are high in developed countries, and are estimated to be lower in less developed geographic areas, including Central/South America and most of Africa. The World Health Organization predicts that lung cancer death rates worldwide will rise as a result of increased global tobacco use, particularly in Asia. While the incidence of lung cancer is low in patients younger than 40 years of age, it starts to rise gradually in later ages and peaks between the ages of 65-84. Although it is more common in the male population in general, changing lifestyle habits indicate that the risk of lung cancer in women increases.
According to the data obtained from the Lung Cancer Map Project, the incidence of lung cancer in our country is 75 per 100 thousand per year in men and 10 per 100 thousand per year in women, and the annual expected number of new patients is approximately 30,000. In Turkey, lung cancer is seen in the first place among men and in the 5th place among women. However, increasing tobacco use in women also increases the risk of lung cancer. In our country, the average age of diagnosis of lung cancer is 63 years, and it is rarely seen under the age of 40. As in the world, the risk of lung cancer increases in Turkey due to tobacco use.
What are the Risk Factors Leading to Lung Cancer?
Any reason that increases the development of cancer in a person is called a 'risk factor'. The fact that you have this risk factor does not mean that you will get cancer, and the absence of risk factors does not mean that you will not get cancer. Identified risk factors for lung cancer; use of tobacco and tobacco products, passive smoking, exposure to asbestos, arsenic, chromium, beryllium, nickel, soot or tar, radon gas, having tuberculosis, family history of lung cancer or other organ cancer, especially high levels of is air pollution.
What are the Symptoms of Lung Cancer?
In patients diagnosed with lung cancer, the symptoms vary depending on the location of the tumor in the lung, its size, the place of spread and the degree of spread. In an individual who smokes or has smoked in the past, persistent cough despite treatment, recurrent pneumonia or frequent exacerbations of chronic obstructive pulmonary disease in the same region are important findings. Shortness of breath and hemoptysis (blood in sputum) are among other important symptoms. Less common symptoms include chest pain and hoarseness.
Nonspecific symptoms such as weight loss, weakness and fatigue may be seen in patients with lung cancer due to the spread of the tumor to extrapulmonary organs. Bone metastases from lung cancer are often painful; brain metastases may be asymptomatic, but neurologic sequelae may manifest according to size and location. Finally, patients may present with paraneoplastic symptoms due to the effects of substances produced by the tumor and acting directly or indirectly.
How is the Diagnosis Made in Lung Cancer?
In the diagnosis of lung cancer, symptoms and physical examination findings are used first. Lung cancer can be detected incidentally in almost half of the patients without any symptoms or signs. Swollen lymph nodes in the neck region, cachexia, abnormal sounds in the lungs, dullness when touching the chest, uneven pupils, drooping eyelids, weakness in one arm, enlarged veins in the arms, chest or neck, and swelling of the face are the findings that should be considered during clinical examination.
When the physician suspects lung cancer as a result of the patient's symptoms and clinical examination, he or she uses different imaging methods and applies further examinations. Methods such as chest X-ray, computed tomography (CT), positron emission tomography (PET-CT), bronchoscopy and biopsy are among the leading ones. The next step is tissue diagnosis. To this end; Bronchoscopy, CT-guided transthoracic needle aspiration, thoracentesis (pleural fluid cytology), video-assisted thoracoscopic surgery and biopsy are invasive diagnostic methods.
What are the Stages of Lung Cancer?
In lung cancer, the stage is important for the physician to plan the treatment and determine the course of the disease. Lung cancers are divided into two main groups as “small cell lung cancer” and “non-small cell lung cancer” according to the appearance of cells viewed under the microscope. About 80% of lung cancers are in the non-small cell group.
Non-Small Cell Lung Cancer (NSCLC) has 4 stages:
Stage 1: The disease is only in a small part of the lung.
Stage 2: The disease has jumped to the nearest lymph nodes or just to the chest wall.
Stage 3: The disease has spread to the space (mediastinum) where the heart is located between both lungs or to the lymph nodes there.
Stage 4: The disease has spread to distant organs such as the brain, liver, bone, adrenal gland.
Small Cell Lung Cancer (SCLC) is staged as “limited disease” and “widespread disease”:
Limited disease: The disease is found on only one side of the rib cage, part of the lung, and adjacent lymph nodes.
Widespread disease: The disease has spread to the other half of the lung or to other parts of the body.
How Can Lung Cancer Be Treated?
The type and stage of lung cancer is the most important factor that determines the treatment. In the early stages of NSCLC (Stage 1 and 2) and in some Stage 3 patients, surgical treatment is applied and the tumor area can be cleaned by removing some healthy tissue from the surrounding area, sometimes by removing a whole lung. In general, no further treatment is required in Stage 1 patients, in which the tumor is completely removed by surgery and no diseased tissue remains. After the surgery, your doctor will call you for a check-up at regular intervals. In some cases (Stage 2 and 3), additional drug therapy (chemotherapy) can be applied to patients after surgery. Sometimes, surgery can be applied to the shrinking tumor with these treatments. Stage 4 NSCLC is not suitable for surgical treatment. The disease can be controlled at this stage with long-term chemotherapy, targeted therapies or immunotherapy. With these treatments, it is possible to completely eliminate the tumor, the patient's life expectancy can be extended and the complaints can be resolved.
Although small cell lung cancer can progress rapidly, it responds very well to chemotherapy and radiotherapy. Therefore, the most appropriate treatment is chemotherapy. The condition in which the disease does not spread to other organs is called 'limited disease' and the addition of radiotherapy to chemotherapy increases the success in patients at this stage. These two treatments can be applied one after the other or simultaneously (simultaneously). The place of surgical treatment is very limited. If the disease is widespread in other organs, the appropriate treatment is chemotherapy. Although it is a very sensitive tumor to chemotherapy, the risk of cancer recurrence is high.
Screening and Prevention in Lung Cancer
Unfortunately, lung x-rays or computed tomography scans for lung cancer screening or searching for cancer cells in sputum do not reduce cancer-related deaths. Annual lung cancer screening can be performed with low-dose computed tomography in people in the risk group. Lung cancer screening is generally recommended for people aged 55 years and older who have smoked heavily for many years.
The only proven effective way to prevent lung cancer is to combat the use of cigarettes and tobacco products. While not starting to smoke is the most effective way, quitting significantly reduces the risk of developing cancer over the years. It is absolutely necessary to prevent young people from starting to smoke, and education should be given in schools.
Prof. Dr. Burcin Celik
Medicana International Samsun Hastanesi
Thoracic Surgery Clinic