What Is Lung Cancer? Symptoms and Treatment

Lung cancer, which ranks first among cancer diseases that lead to death worldwide, is a significant public health issue that causes the death of over 1.7 million people each year. The symptoms and signs that appear in the early stages of the disease are often unnoticed, and critical symptoms like coughing, especially in smokers, are largely overlooked. This situation leads to lung cancer being detected at very late stages, significantly reducing the chances of treatment. Having accurate information about lung cancer, being able to recognize early symptoms, and regularly participating in screening programs in the presence of risk factors are crucial for properly diagnosing and treating lung cancer.

What Is Lung Cancer?

Lung cancer primarily consists of two different types: small cell lung cancer and non-small cell lung cancer. The clinical characteristics of the disease, the biological behaviors of cancer cells, and the treatment principles vary significantly depending on the type of lung cancer.

About 80-85% of lung cancers are non-small cell lung cancer. These cancers can further present in three different forms: adenocarcinoma, squamous cell lung cancer, and large cell carcinoma. As in many parts of the world, adenocarcinoma is the most common type of lung cancer in our country, particularly observed more frequently in women, young individuals, and non-smokers. Squamous cell cancers account for 25-30% of non-small cell lung cancers, and these tumors, which tend to be centrally located, are more associated with smoking. Large cell carcinomas are responsible for approximately 15% of lung cancers.

Small cell lung cancer is seen in 10-15% of cases. Smoking is again the most significant factor in the formation of these tumors. Small cell lung cancers tend to spread and multiply rapidly. Despite being sensitive to chemotherapy and radiotherapy due to these characteristics, the disease recurrence is frequently observed in many patients.

Other rare types of lung cancer include carcinoids, adenosquamous carcinoma, and sarcomas.

What Are the Types of Lung Cancer?

Lung cancers can be classified according to the type of cells that cause the cancer:

• Squamous cell carcinoma
• Adenocarcinoma
• Large cell carcinoma
• Adenosquamous carcinoma
• Sarcomatoid carcinomas
• Neuroendocrine tumors (small cell carcinoma, others…)

Symptoms of Lung Cancer

Many lung cancer cases may not show symptoms until the disease has progressed. One of the initial symptoms, cough, is often perceived as a normal condition by smokers, further delaying the detection of the disease in its early stages. It is extremely important to be aware of the symptoms associated with lung cancer to recognize the disease early. Common symptoms observed in cancer cases include:

Coughing
Cough is the most common symptom associated with lung cancer. About 75% of patients encounter a persistent cough during the early stages of the disease, but the majority do not consider this an abnormal condition since they attribute it to smoking. As a result, the symptom of cough seen in the early stage is often overlooked.

Shortness of Breath
The tumor that develops with cancer can cause narrowing of the airways, fluid accumulation in the lung lining, and loss of movement in the diaphragm muscle. All these conditions can lead to complaints of dyspnea (shortness of breath) and difficulty breathing.

Chest Pain
Although lung tissue is devoid of pain sensation, pain complaints can arise in areas where tumor cells spread. When lung cancer metastasizes to the chest wall or to the brachial plexus (a network of nerve cells located in the armpit), patients may experience chest pain and pain in the upper arm or shoulder.

Sudden Weight Loss
As with all cancer diseases, sudden weight loss can occur in lung cancer. However, this symptom often appears in the later stages of cancer or in the presence of liver metastasis.

Hemoptysis
Hemoptysis, or coughing up blood, is one of the significant symptoms seen in some lung cancer cases. It usually arises as a result of the tumor spreading to the upper respiratory tract.

Recurrent Lung Infections
Especially in individuals with a long history of smoking, recurrent or unresolved pneumonia attacks can be a sign of lung cancer.

Which Organs Does Lung Cancer Metastasize To?

Lung cancer can metastasize to various organs and tissues, including the brain, bones, liver, digestive system, pleura (lining of the lungs), pericardium (heart lining), adrenal glands, skin, and soft tissues.

What Are the Causes of Lung Cancer?

Smoking: 80-90% of lung cancer patients have a history of smoking, making it one of the primary risk factors for lung cancer. Factors influencing the risk of cancer development include the age of onset of smoking, duration of smoking, type of cigarettes smoked (e.g., filtered, unfiltered, cigars, low tar, and nicotine content, etc.), and the daily amount smoked. Compared to non-smokers, smoking increases cancer risk by 10-30 times, especially after 20 pack-years. Exposure to passive smoke also increases lung cancer risk similarly. Smoking is directly linked to lung cancer in 90% of women and 79% of men. Quitting smoking does not completely eliminate the risk of cancer, but it does reduce it.

Environment: Industrial and environmental factors are significant in the development of lung cancer. Exposure to substances such as radon gas, asbestos, air pollution, radioisotopes, heavy metals, and mustard gas has been linked to lung cancer.

Genetics: Hereditary factors are believed to play a role in the development of lung cancer. If there is a family history of lung cancer, the risk of developing the disease increases by 2.4 times.

Viruses: Individuals with HIV infection have a higher likelihood of developing lung cancer.

Radiation: Radiation from any source can damage lung tissue, leading to alterations in bronchial cells' structure and carcinogenesis.

How Does Lung Cancer Develop?

When the cells in the respiratory tract are exposed to carcinogenic factors for an extended period, mutations may develop in the lung bronchial cells. These chronic exposures can lead to a series of mutations that cause cancerous changes in the cells. Such abnormal cells can develop in anyone, but a sufficient immune system recognizes and eliminates or repairs these cells. If there is a weakness in the organism's immune system, the uncontrolled proliferation of these structurally altered cells increases, leading to the formation of cancer masses. Additionally, with further changes in their biological structure, these cells gain the ability to metastasize and begin to spread to distant organs.

How Is Lung Cancer Diagnosed?

The definitive diagnosis of lung cancer occurs through imaging of the tumor. Based on significant points in the patient's history and findings detected during clinical examination, a general opinion is formed; however, these symptoms must be supported by laboratory and radiological investigations. The primary tests used for lung cancer diagnosis include chest X-ray, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), bronchoscopy, transthoracic fine needle aspiration biopsy, mediastinoscopy, thoracoscopy, video-assisted thoracic surgery (VATS), and thoracotomy.

Initially, the direct X-ray method is utilized, which can reveal images indicating disease, such as nodules, infiltrations, hilar fullness, atelectasis, mediastinal widening, the presence of fluid in the pleura, and increased regional translucency. Subsequently, the CT scan of the lungs is performed as a second test to obtain important findings regarding the general structure of the lesion causing the mass, cellular distribution, hilar area, mediastinal involvement, and lymphadenopathy in this region. In the later stages, other imaging methods deemed necessary by the physician may be applied to determine important points such as staging of the disease, the choice of treatment method, and detection of organ involvement.

Lung Cancer Treatment Methods

To choose the appropriate treatment method for lung cancer, it is essential first to identify the type of cancerous cell and accurately define the stage of the cancer.

In early-stage non-small cell lung cancer, the most definitive treatment method is the surgical removal of the cancerous mass. All cancer patients who can undergo surgery should have their opportunities assessed, and the focus should be on removing the mass through surgical operation initially. Depending on the stage of the disease, treatment methods such as chemotherapy (drug therapy), immunotherapy, targeted drugs, and radiotherapy (radiation therapy) may be added in the subsequent process.

In small cell lung cancer, early-stage treatment involves the combined application of chemotherapy and radiotherapy. The role of surgical treatment in this tumor type is very limited.

Lung Cancer Screening Methods

In a study conducted among high-risk groups defined as individuals over 55 years old, heavy smokers (30 pack-years), or those who smoked at that intensity and quit no more than 15 years ago, screening with low-dose lung computed tomography (CT) showed a 20% reduction in lung cancer-related mortality compared to lung X-rays. Based on these results, annual low-dose CT screening is recommended for high-risk groups. However, it should be remembered that the recommended tomographic screening will never replace quitting smoking.

What Are the Stages of Lung Cancer?

Lung cancer is classified into four stages:

• Stage 1: The tumor is only in the lung.
• Stage 2: The cancer has spread to nearby lymph nodes.
• Stage 3: The tumor has spread to the pleura or the mediastinal cavity between the two lungs.
• Stage 4: The disease has spread to distant organs such as bones, liver, adrenal glands, and brain.

Staging of lung cancer is essential for treatment planning. If lung cancer is detected in the first or second stage, the success rate of treatment is higher. Tumor cells in the lung tissue are surgically removed, and a protective treatment plan is arranged based on the doctor's decision. If the disease is in an advanced stage, methods such as chemotherapy, targeted therapies, immunotherapy, and radiotherapy are determined by the doctor according to the cell type and stage.

What Are the Chances of Treatment for Lung Cancer?

The course of lung cancer varies depending on the tumor's cell type, the stage of the disease, the findings detected at the time of diagnosis, the size of the tumor, and the rate of disease spread.

In the majority of early-stage cases where metastatic disease is not detected, there is a chance of recovery with surgical treatment, complemented by radiotherapy and chemotherapy if necessary. Although significant advancements have been made in treatment methods for advanced-stage disease, the likelihood of recurrence is higher. Prolonged chemotherapy, targeted therapies, or immunotherapies can provide long-term control of the disease in these stages. However, due to the risk of developing resistance to treatments and the potential for disease progression, radiological monitoring is required at regular intervals. As a result, survival rates are higher for cancers that are caught in early stages and can be surgically removed.