What is lung cancer?
Lung cancer is the formation of a mass (tumor) in lung secondary to uncontrolled and unnecessary proliferation of cells that are located in structurally healthy lung tissue. Next, this mass starts enlarging at the original location and in subsequent phases, it invades surrounding tissues, followed by distant organs (liver, bone, brain etc.) as it spreads through blood circulation. Among all types of cancer, lung cancer is the most common cause of death for men and the second most common cause of death for women. Approximately 1.3 million people die due to lung cancer around the world every year. However, novel treatment methods have prolonged survival and increased quality of life.
Types of Lung Cancer
Lung cancers are categorized into two groups that represent different types of cells and require different treatments. Treatment methods vary for two groups:
- Non-small cell lung cancer (NSCLC)
- Small cell lung cancer
Small cell lung cancer is characterized with rapid progression and presence of distant metastases at diagnosis. Non-small cell lung cancer accounts for 85% of patients, while small cell lung cancer accounts for the rest cases.
Stages of the Lung Cancer
Different methods are available to stage lung cancer;
- CT – Computed Tomography
- MRI – Magnetic Resonance Imaging
- PET/CT – Positron Emission Tomography / Computed Tomography
- Bone scan
- Mediastinoscopy/Mediastinotomy: Both procedures are invasive in nature and show whether cancer spread to lymph nodes located in the rib cage.
Small cell lung cancer is staged as localized disease and metastatic disease. There are four stages of non-small cell lung cancer. While Stages 1 and 2 implies a local disease, Stages 3 and 4 are characterized with metastasis to distant organs through lymphatic system and blood circulation.
What are the symptoms of the lung cancer?
The disease may not lead to significant complaints until it progresses into advanced stages. The asymptomatic progression is the most important factor that makes lung cancer so dangerous. Following symptoms should lead to cancer suspect;
For a smoker who has resultant chronic bronchitis, conversion of seasonal cough and secretion in a chronic form, gradually progressing shortness of breath, blood in sputum, sharp chest pain radiating to back – especially inter-scapular region-, idiopathic weight loss, hoarseness, wheezing and feeling extremely tired.
Lung cancer is not remarkably manifested in early stage, although cough, wheezing, labored breathing and chest discomfort are experienced by some patients. It can be incidentally diagnosed in a chest X-ray or CT that is scanned for other reasons.
What are the diagnostic methods of the lung cancer?
Your doctor can order one or more than one test, such as chest X-ray or computed tomography scan of chest, to determine whether there is a mass lesion in your lung(s). If an abnormality is found in your lung(s), PET/CT is scanned to evaluate the lesion and next, biopsy specimen will be taken to examine structure of the mass lesion. A tissue specimen is taken from the suspected zone of the lung and examined under microscope to characterize the disease. Tissues can also be taken from nearby lymph nodes.
- Bronchoscopy: it is based on inserting a tiny tube with a light source into mouth cavity and examining the respiratory tract. A small tissue piece is taken from the bronchial mucosa at or nearby the location of the suspected lesion or the tumor.
- Needle aspiration: a biopsy needle is inserted through the chest wall and advanced to the location of tumor to take a small tissue piece from the tumor. Radiology guidance is required for this procedure.
- Thoracentesis: The fluid that surrounds lungs is sampled using a biopsy needle.
Thoracotomy: Rib cage is surgically opened in order to directly take a tissue specimen from the tumor. If cancer cells are identified in the biopsy specimen, extent of spread (stage) is investigated with tests.
What are the risk factors of the lung cancer?
There are various risk factors that trigger occurrence of lung cancer. Smoking cigarette or cigar, smoking a pipe, passive smokers (ones who are exposed to smoke of cigarette), exposure to toxic gases and asbestos, air pollution and lung diseases (prior history of tuberculosis) are factors that increase risk of catching the disease.
Recurrence rate is higher in a person, who has caught the disease once, than a person with no personal history of this cancer. Some occupations set the ground for the lung cancer. These occupations include mining, textile, insulation, plastic – industry, petro-chemistry, dye, metallurgy and welding works in shipyards.
Treatment Methods for the Lung Cancer
Non-small cell lung cancer (NSCLC): selection of treatment depends on extent of the spread. In this group of lung cancer, surgery is the most common or first-line treatment modality. Radiotherapy and chemotherapy are used to slow down the progression and to manage symptoms.
Small cell lung cancer (SCLC): Many cases present with metastatic tumor(s) in other body region(s), when the condition is first diagnosed. Therefore, surgery can be used in very rare cases of small cell lung cancer. Doctors usually prefer chemotherapy to destroy cancer cells that had already spread to the body. Treatment, also including chemotherapy, can target the tumor located in the lung or metastatic tumors located in other body regions. Radiotherapy for brain can be considered for some patients, even if there is no cancer there. This is referred as prophylactic cranial radiotherapy. Radiotherapy is used to prevent the occurrence of metastasis to the brain. One or more than one of following treatments can be used depending on size, spread and pathological type of the tumor:
- Surgery (surgical removal of the lung cancer)
- Chemotherapy (medications therapy); neo-adjuvant (before surgery) and adjuvant (after surgery)
- Radiotherapy (irradiation)