TürkçeSquamous cell carcinoma of the lung is one of the subtypes of non-small cell lung cancer (NSCLC) and typically develops near the major bronchi. This type of tumor is most commonly associated with cigarette smoking and is seen more frequently in men.
The characteristic feature of squamous cell carcinoma is that it originates from squamous epithelial cells. These cells normally line the inner surface of the airways. As the tumor grows, it may obstruct the airway, causing symptoms such as cough, bloody sputum, and shortness of breath.
This type of cancer generally grows more slowly and tends to remain localized during the early stages. However, over time it may spread to the lymph nodes and distant organs. Diagnosis is made through histopathological examination using imaging studies, bronchoscopy, and biopsy.
The treatment process may include surgery, chemotherapy, radiotherapy, and targeted therapies depending on the stage of the disease. Surgical treatment is more feasible in the early stages. In advanced stages, combined treatment strategies are used to improve survival and quality of life.
What Are the Main Causes and Risk Factors of Squamous Cell Carcinoma of the Lung?
Although many different factors that disrupt the cellular structure may contribute to the development of this disease, the strongest scientifically proven cause worldwide and in our country is the use of tobacco and tobacco products. Under normal conditions, our airways are lined with a highly delicate protective layer responsible for clearing inhaled dust and microorganisms. However, with every cigarette smoked over many years, thousands of harmful chemicals directly and continuously attack this sensitive lining. Over time, these chemicals alter the genetic code of the cells and initiate the cancer development process. In fact, the statistical likelihood of this specific type of cancer occurring in individuals who have never used tobacco products throughout their lives is extremely low.
The risk is not limited only to the cigarettes smoked by the individual. Long-term passive exposure to secondhand smoke poses a serious threat by triggering the same type of cellular damage in the lungs as active smoking. Particularly in enclosed environments, prolonged exposure to tobacco smoke may silently advance the process of cellular deterioration.
In addition, certain invisible substances inhaled in our homes or workplaces also create significant risks. For example, radon gas, a colorless, odorless radioactive gas naturally found in the soil that can seep into buildings through their foundations, is an important threat to lung health. Likewise, long-term occupational exposure without adequate protective equipment to asbestos, arsenic, nickel, chromium, and various coal-derived chemicals used in industrial settings can cause irreversible damage to the airways. Previous severe lung infections as well as chronic lung diseases such as chronic bronchitis and emphysema are also considered factors that promote cellular transformation.
The primary risk factors that contribute to the development of this disease include:
- Active cigarette smoking
- Passive smoking
- Radon gas exposure
- Asbestos exposure
- Arsenic exposure
- Nickel exposure
- Chromium exposure
- Advanced age
- Genetic predisposition
- Chronic lung diseases
How Does Squamous Cell Carcinoma of the Lung Begin and Progress at the Cellular Level?
The development of this disease is not a sudden event but rather the result of a struggle that continues at the cellular level for many years and eventually fails. The inner surface of a healthy bronchus is lined with cells bearing tiny hair-like structures called cilia. These cilia continuously work to remove foreign particles entering the lungs. However, when these ciliated cells are damaged by heavy tobacco smoke or chemical gases, the body develops an impressive defense mechanism by replacing these delicate cells with much tougher, flatter, and more durable squamous cells. This process is called metaplasia and initially represents the body’s attempt to protect itself.
Unfortunately, when exposure to harmful substances continues uninterrupted for many years, this protective mechanism also begins to deteriorate. These newly formed squamous cells gradually become abnormal, lose their organized structure, and develop genetic alterations under continuous chemical assault. This stage, in which the cells appear abnormal but have not yet invaded surrounding tissues, represents the earliest silent phase of the disease.
During the final and most dangerous stage, these genetically damaged cells acquire the ability to multiply uncontrollably and begin invading deeper lung tissues beyond their original location. At this point, the tumor mass progressively enlarges. One of the most important characteristics of squamous cell carcinoma is its tendency to invade nearby lymphatic channels and blood vessels as it grows. Once these pathways are reached, cancer cells gain the potential to spread throughout the body.
What Symptoms Are Observed in Patients with Squamous Cell Carcinoma of the Lung?
Because this disease usually develops in the trachea or major bronchi, symptoms that affect the patient’s quality of life often appear relatively early. While cancers located in the outer parts of the lungs may remain silent for a long time, squamous cell carcinoma directly disrupts respiratory function by obstructing or irritating the central airways.
The most common complaint leading patients to seek medical attention is a persistent cough that changes in character and does not resolve. Individuals who have smoked for many years often become accustomed to their morning cough and may not consider it important. However, as the tumor grows within the airway, the cough becomes more severe, persists throughout the day, and may even awaken the patient from sleep. When the tumor erodes the highly vascular lining of the airway, blood may appear in the sputum, which is an important warning sign requiring prompt medical evaluation.
As the tumor enlarges and acts like a plug within the airway, airflow into and out of the lungs becomes increasingly restricted. Initially, patients experience shortness of breath only during physical activity, but eventually it may occur even at rest, accompanied by wheezing during breathing. Secretions accumulating behind the obstructed airway create an ideal environment for bacterial growth, resulting in recurrent pneumonia-like lung infections that do not completely resolve despite repeated courses of antibiotics. Once the tumor reaches the pleura or chest wall, a dull, persistent chest pain that worsens with deep breathing may also develop.
The main symptoms associated with this disease include:
- Persistent cough
- Bloody sputum
- Shortness of breath
- Wheezing
- Chest pain
- Hoarseness
- Difficulty swallowing
- Recurrent infections
- Loss of appetite
- Weight loss
- Severe fatigue
Which Radiological Imaging Methods Are Used When Squamous Cell Carcinoma of the Lung Is Suspected?
When patients present with symptoms such as respiratory distress or bloody sputum, modern radiological imaging technologies are used to detect the disease and accurately map its location. The first and most fundamental step is computed tomography (CT), which provides millimeter-thin cross-sectional images of the chest. CT scans visualize the lungs, airways, blood vessels, and surrounding tissues with remarkable clarity. Suspicious masses in the central airways, airway obstructions, or lung collapse caused by the tumor can be clearly identified. Squamous cell carcinomas typically appear on CT as well-defined masses with central cavitation or areas of tissue breakdown.
Once a suspicious lesion is detected on CT, positron emission tomography (PET), commonly known as a PET scan, is performed to determine the biological activity of the tumor and whether it has spread elsewhere in the body. This technique is based on the metabolic characteristics of cancer cells. Since cancer cells divide rapidly, they consume far greater amounts of glucose than normal tissues. Radioactively labeled glucose molecules injected into the bloodstream circulate throughout the body and are avidly taken up by cancer cells. The scanner detects these areas of increased glucose uptake, highlighting the primary tumor as well as any suspicious lymph nodes or distant metastatic sites in a single examination.
In addition, even if there are no neurological symptoms, cranial magnetic resonance imaging (MRI) is considered an essential part of the diagnostic evaluation because this type of cancer carries a risk of spreading to the brain. MRI provides highly detailed images of brain structures without exposing the patient to radiation.
Which Biopsy Methods Are Used to Confirm the Diagnosis of Squamous Cell Carcinoma of the Lung?
No matter how suspicious imaging findings may appear, a definitive diagnosis of cancer and determination of its specific subtype require microscopic examination of tissue obtained from the suspicious lesion. Because squamous cell carcinoma is most commonly located in the central airways, tissue sampling is usually performed using bronchoscopy, a safe and practical procedure.
During bronchoscopy, a thin, flexible tube equipped with a small camera and light source is inserted into the patient’s airways. The inner lining of the trachea and bronchi is directly visualized on a monitor. Once the tumor is identified, tiny instruments passed through the bronchoscope are used to obtain tissue samples or collect cells with specialized brushes. Since the procedure is generally performed under sedation, patients usually experience little or no discomfort.
Sometimes suspicious involvement exists not only in the primary tumor but also in the lymph nodes located in the mediastinum, the area between the lungs. In such cases, one of modern medicine’s most advanced techniques, endobronchial ultrasonography (EBUS), is used. This system incorporates a miniature ultrasound probe at the tip of the bronchoscope. While inside the airway, the physician can visualize lymph nodes located beyond the airway wall. Once the target lymph node is identified, a fine needle is passed through the bronchoscope to obtain a sample directly from the lymph node. More rarely, if the tumor is located in the outer regions of the lung, a CT-guided needle biopsy may be performed through the chest wall.
The main diagnostic methods include:
- Chest X-ray
- Computed tomography
- Positron emission tomography
- Magnetic resonance imaging
- Fiberoptic bronchoscopy
- Endobronchial ultrasonography
- Needle biopsy
- Histopathological examination
How Is Squamous Cell Carcinoma of the Lung Staged and Why Is It Important?
After the diagnosis has been confirmed, the next critical step is determining the extent of the disease throughout the body. This process, known as staging, serves as the roadmap for selecting the most appropriate treatment. Thoracic surgeons rely on staging to determine whether surgery is feasible, how extensive the operation should be, and which additional treatments may be necessary. This evaluation follows an internationally accepted system that assesses the primary tumor, lymph node involvement, and distant metastasis.
The first factor involves the physical characteristics of the tumor itself. The size of the tumor, the amount of lung tissue involved, and whether it has invaded critical structures such as the chest wall, pericardium, or main bronchus are carefully evaluated. Smaller tumors with limited local invasion generally offer a greater chance of successful surgical treatment.
The second and often most influential factor in determining surgical eligibility is the status of the regional lymph nodes. The lymphatic system serves as the body’s drainage and immune network. Cancer cells often spread first to lymph nodes within the lung and later to those located between the lungs. When involvement remains confined to lymph nodes on the same side of the chest, surgery remains a strong treatment option. However, if cancer has spread to lymph nodes on the opposite side of the chest or to the neck region, systemic therapy is generally recommended before surgery.
The third factor is whether the disease has spread beyond the lungs to distant organs such as the brain, liver, adrenal glands, or bones. Although squamous cell carcinoma often remains localized when detected early, identification of distant metastases shifts treatment away from local surgery toward systemic therapies provided by medical oncology.
How Is the Patient’s Physical Condition Evaluated Before Surgery for Squamous Cell Carcinoma of the Lung?
The fact that a tumor appears technically removable on imaging does not automatically mean that surgery can be performed immediately. Most patients with squamous cell carcinoma have a long history of heavy smoking, meaning they often face not only cancer but also smoking-related conditions such as chronic bronchitis, chronic obstructive pulmonary disease (COPD), cardiovascular disease, and reduced exercise capacity. Therefore, careful assessment of the patient’s physiological reserve is essential before surgery.
Detailed pulmonary function tests are performed to evaluate respiratory capacity. These tests measure how much air the patient can forcefully exhale and how efficiently oxygen is transferred from the lungs into the bloodstream. Since a portion of the lung will be removed during surgery, mathematical calculations are used to determine whether the remaining healthy lung tissue will be sufficient for independent daily living.
Removing part of the lung affects not only breathing but also the workload of the heart. Reduction of the pulmonary vascular bed requires the right side of the heart to work harder. Therefore, preoperative evaluation includes electrocardiography, echocardiography to assess heart muscle function and heart valves, and coronary angiography when necessary. Simple exercise assessments, such as climbing two flights of stairs without stopping or completing a six-minute walk test, provide valuable information about the patient’s ability to tolerate postoperative recovery.
The main aspects evaluated during the preoperative assessment include:
- Pulmonary function testing
- Oxygen transfer capacity
- Electrocardiography
- Echocardiography
- Exercise stress testing
- Stair climbing test
- Six-minute walk test
- Blood tests
- Kidney function
- Liver enzyme levels
What Modern Thoracic Surgical Techniques Are Used in the Treatment of Squamous Cell Carcinoma of the Lung?
When the disease is detected at an early and localized stage, surgery remains the cornerstone of treatment and offers the greatest chance of cure. The primary goal of thoracic surgery is to remove the tumor completely, along with a margin of healthy tissue, while meticulously removing all suspicious lymph nodes. Thanks to remarkable advances in medical technology, procedures that once required opening the chest through large incisions can now be performed using minimally invasive techniques that reduce patient discomfort.
In video-assisted thoracoscopic surgery (VATS), the ribs are neither spread apart nor cut. Instead, a high-definition camera and long, specialized instruments are introduced through one to three small incisions made in the side of the chest. The surgeon performs the procedure while viewing magnified images of the chest cavity on large monitors. Because tissue trauma is minimal, patients experience less postoperative pain, shorter hospital stays, and faster recovery.
The most advanced form of minimally invasive surgery is robot-assisted thoracic surgery. In this technique, the surgeon operates from a specialized console rather than standing beside the patient. Sensors attached to the surgeon’s fingers translate hand movements into highly precise movements performed by robotic arms inside the patient’s chest. Three-dimensional visualization and instruments with a greater range of motion than the human wrist provide exceptional precision and safety, particularly when operating near the heart and major blood vessels.
The extent of surgery depends on the location of the tumor. If the tumor is confined to a single lung lobe, complete removal of that lobe remains the standard procedure. However, because squamous cell carcinoma often develops near the central airways, surgeons may perform bronchoplastic or sleeve resections to preserve healthy lung tissue instead of removing the entire lung. In these procedures, the affected segment of the main bronchus is removed, and the healthy bronchus is reconnected to the remaining lung, preserving lung function.
The principal surgical techniques include:
- Video-assisted thoracic surgery
- Robot-assisted surgery
- Open surgery
- Lobectomy
- Segmentectomy
- Pneumonectomy
- Bronchoplastic resection
What Additional Medical Treatments Are Given Alongside Surgery for Squamous Cell Carcinoma of the Lung?
Successful cancer treatment is achieved through close collaboration between thoracic surgeons, medical oncologists, and radiation oncologists. Depending on the stage of the disease, powerful medical therapies may be incorporated to enhance surgical effectiveness or make surgery feasible.
If the tumor is larger, more advanced, or has spread extensively to nearby lymph nodes at diagnosis, treatment usually begins with chemotherapy, radiotherapy, or both before surgery. These treatments help shrink the tumor, separate it from surrounding critical structures, and make surgery technically safer. In recent years, the addition of immunotherapy before surgery has revolutionized treatment, with some tumors showing dramatic responses and significantly improving surgical outcomes.
Even after successful surgery, treatment does not necessarily end. Following detailed pathological examination of the removed tissue, if there is a significant risk that microscopic cancer cells remain in the bloodstream or lymphatic system, additional therapy may be recommended to reduce the likelihood of recurrence. Alongside conventional chemotherapy, modern immunotherapy agents provide long-term protection and significantly improve the chances of lasting recovery.
What Is the Recovery Process and What Are the Risks After Surgery for Squamous Cell Carcinoma of the Lung?
Following such a major surgical procedure, the postoperative hospital period requires as much attention and care as the operation itself. Surgical success depends not only on complete tumor removal but also on a smooth recovery and restoration of normal function. After surgery, patients typically have a silicone chest drain placed to remove excess fluid and any air leaking into the chest cavity.
Postoperative pain during the first few days is completely normal and is effectively controlled with modern pain management techniques. Adequate pain control is crucial because patients who are comfortable can breathe deeply, cough effectively, and begin walking early. Regular use of breathing devices helps keep the remaining lung fully expanded and reduces the risk of postoperative lung collapse.
Some patients may experience mild air leakage from the surgical site for several days. This usually resolves spontaneously while the chest tube remains in place. However, in patients whose lungs have been severely damaged by COPD or emphysema, prolonged air leakage, extended chest tube duration, bleeding, or infection may occasionally occur. Throughout this period, physicians and nurses monitor patients closely and intervene promptly whenever necessary.
Possible conditions encountered during recovery include:
- Lung collapse
- Prolonged air leak
- Bleeding
- Cardiac arrhythmia
- Infection
- Pain
- Fatigue
How Does the Follow-up Process Proceed After Treatment for Squamous Cell Carcinoma of the Lung?
After surgery and any necessary additional treatments have been completed, patients remain under lifelong follow-up by thoracic surgery and oncology teams. The only way to maintain successful treatment outcomes in lung cancer is through consistent and regular follow-up. Statistically, the highest risk of recurrence occurs during the first two years after treatment.
During this critical period, patients are generally evaluated every three to six months. At each visit, a physical examination is performed, blood tests are reviewed, and chest CT scans are obtained to assess the lungs. If any suspicious changes are identified, additional imaging studies are promptly arranged. Once the first two years have passed without recurrence, patients usually continue with annual follow-up examinations for the rest of their lives. Throughout this long journey, the patient’s greatest responsibility is to permanently eliminate tobacco use, maintain healthy nutrition, and incorporate prescribed breathing exercises into daily life.
Prof. Dr. Alper Fındıkcıoğlu graduated from Istanbul University Faculty of Medicine and completed his thoracic surgery residency at Dr. Siyami Ersek Hospital. He began his academic career at Başkent University in 2005; he received the title of associate professor in 2014 and professor in 2022. He has extensive experience in lung cancer, chest wall diseases, and minimally invasive surgery. Since 2024, he has been continuing his professional work at Acıbadem Hospital.
