Lung Cancer

Ocak 31, 2024
Lung cancer is a type of cancer that occurs as a result of uncontrolled growth and proliferation of cells in the lungs.

What is Lung Cancer?

 Lung cancer is a type of cancer that occurs due to the uncontrolled growth and multiplication of cells in the lungs. The primary function of the lungs is to take in oxygen necessary for the body's vital functions and to remove carbon dioxide produced during this process. Cancerous cells that proliferate uncontrollably grow in their environment and spread to surrounding tissues, causing damage.

It is the most diagnosed and the leading cause of death from cancer both globally and in Turkey. It accounts for about 19.4% of all cancer-related deaths, which is higher than the combined number of patients lost annually to breast, colon, and prostate cancer.

Lung cancer is generally categorized into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC).

Stage I and stage II NSCLC are considered early stages. However, since it often progresses without symptoms, most diagnosed patients are in stage III or stage IV.

Lung Cancer Types

Lung cancer can be classified into various types based on the structure and characteristics of the cancer cells. Some types include:

Lung Cancer Causes

The primary cause of lung cancer is cigarette smoking due to carcinogenic substances found in cigarette smoke. However, lung cancer can also occur in non-smokers. Apart from smoking, passive smoking, genetic factors, aging, air pollution, occupational exposure, and radiation exposure are contributing factors to lung cancer.

Lung Cancer Symptoms

Lung cancer progresses silently and often shows symptoms in advanced stages. Persistent cough is the primary lung cancer symptom, followed by shortness of breath, chest pain, and coughing up blood. Compression or involvement of the vocal cord nerve can cause hoarseness. Phrenic nerve involvement may lead to diaphragm paralysis. Tumors located in the upper right lobe can cause swelling and redness in the neck and face due to compression on the superior vena cava. Tumors in the apex of the lung can cause Pancoast syndrome, leading to shoulder pain, weakness in the arm, and Horner's syndrome (drooping eyelid, smaller pupil, and decreased sweating on the same side of the face). Approximately 30% of diagnosed lung cancer patients can develop pleural effusion (fluid buildup in the lungs). Additionally, other general symptoms seen in many other cancer types, such as loss of appetite, weight loss, and fatigue, can also be symptoms of lung cancer.

Consulting a healthcare professional is crucial if any of the following symptoms are experienced:

Lung Cancer Diagnosed

Lung cancer diagnosis typically involves a patient's medical history, physical examination, complete blood count, and laboratory tests, followed by imaging and interventional procedures. Sputum cytology, which involves examining mucus samples taken from the lungs under a microscope, is a simple and cost-effective diagnostic method, particularly preferred for centrally located tumors.

Radiological diagnostic methods used for lung cancer diagnosis include:

Interventional diagnostic methods used for lung cancer include:

Lung Cancer Stages

Staging lung cancer is primarily based on imaging tests, bronchoscopy, biopsy, and other medical test results. The spread of cancer in the body occurs through a process called metastasis, where cancer cells break away from the original tumor, enter the bloodstream or lymphatic system, and spread to other areas or directly invade tissues and organs. Lung cancer most commonly metastasizes to lymph nodes, brain, liver, bones, adrenal glands, pleura, and other parts of the lungs.

The staging of non-small cell lung cancer (NSCLC) is determined as follows:

Stage I: The tumor is only in a small part of the lung and has not spread to any lymph nodes.

Stage II: The disease has spread to nearby lymph nodes or has skipped to the pleura surrounding the chest, diaphragm, lung, or heart.

Stage III: The tumor has spread to the mediastinum (the space between the lungs) or to the lymph nodes here, or there is involvement of the pleura, chest wall, or diaphragm with lymph node spread.

Stage IV: The tumor has spread to distant organs or the other lung, or there's fluid buildup between the lung or heart linings.

Small cell lung cancer (SCLC) is staged as "limited disease" or "extensive disease":

Limited disease: Cancer is present on only one side of the chest, in a part of the lung, and in adjacent lymph nodes.

Extensive disease: Cancer has spread to the other side of the lung or other parts of the body.

Recently, the staging system used for NSCLC has been proposed to be used in staging SCLC as well.

Lung Cancer Treatment

The treatment of lung cancer depends on the cell type, tumor stage, molecular characteristics, and the patient's overall condition. Patients with stage I and stage II can be treated with complete surgical resection if there are no contraindications (inability to use medication or medical products). For non-surgical patients, conventional or stereotactic radiotherapy can be considered. In locally advanced stages, chemoradiotherapy is used, and for advanced stages, chemotherapy, supportive care, targeted therapy, or immunotherapy are applied.

In recent years, targeted treatment methods have been developed for advanced lung cancer. These involve identifying genetic changes (EGFR, ALK, k-RAS, etc.) in cancerous tissue samples taken for diagnosis and directly using drugs that target these changes. Percutaneous thermal ablation methods can be tried in advanced NSCLC.

Additionally, in cases of tumors blocking the airways (trachea or major bronchi), methods such as laser therapy, photodynamic therapy, electrocautery, cryoablation, and placement of an airway stent can be used to relieve the obstruction. These treatment options can be used post-surgery, radiotherapy, or chemotherapy for palliation. The primary goal of managing advanced-stage SCLC is to maintain quality of life, minimize treatment complications, and extend survival.

How Can Lung Cancer Be Prevented?

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