Lung Cancer

Lung Cancer

What is lung cancer?

Cancer is a group of diseases in which the cells of an organ or tissue escape the body's normal growth control and show uncontrolled growth and multiplication. These cells form masses called tumors. Malignant (cancerous) tumor cells can invade surrounding tissues and damage them, and can travel through blood and lymphatic vessels to distant organs, where they form new tumor deposits (metastases).

Lung cancer is the general term for malignant tumors that arise from the cells of the lung tissue or of the airways (bronchi). It is one of the leading causes of cancer-related death worldwide. In recent years, however, the management of the disease has changed substantially thanks to better options for early detection, minimally invasive surgery, advanced radiotherapy techniques and, in particular, targeted therapies and immunotherapy.

Risk factors and causes

Several factors usually act together in the development of lung cancer. The main known risk factors are:

• Smoking and tobacco products: The most important and most preventable risk factor. The risk rises with the amount and duration of smoking. After quitting, the risk gradually falls; the earlier a person quits, the greater the benefit.
• Passive (second-hand) smoking: Non-smokers who are regularly exposed to tobacco smoke also have an increased risk.
• Radon gas: A colorless, odorless gas that comes from soil and building materials and can accumulate indoors. It is one of the best-known causes after smoking.
• Occupational exposures: Asbestos, arsenic, chromium, nickel, cadmium, silica, certain chemicals and diesel exhaust can raise the risk, and the effect is markedly greater when combined with smoking.
• Air pollution: Long-term exposure to fine particulate matter slightly increases the risk.
• Family history and genetic predisposition: People with a first-degree relative who had lung cancer may be at higher risk.
• Previous lung disease and chest radiotherapy: Chronic obstructive pulmonary disease (COPD), pulmonary fibrosis and previous radiotherapy to the chest may increase the risk.

Lung cancer can also occur in people who have never smoked. In these patients the disease is often associated with specific genetic changes (driver mutations).

Symptoms

In its early stages, lung cancer often causes no symptoms at all. For this reason it is frequently discovered by chance on a chest X-ray or CT scan performed for another reason. When symptoms do appear, they may include:

• A persistent cough lasting more than three weeks, or a cough that changes in character
• Coughing up blood or blood-stained sputum (hemoptysis)
• Shortness of breath or wheezing
• Chest, shoulder or back pain
• Hoarseness
• Unexplained weight loss, loss of appetite and fatigue
• Recurrent lung infections (pneumonia, bronchitis) or infections that do not respond adequately to treatment

These symptoms can have many other causes. Even so, long-lasting complaints, especially in people with a smoking history, should always be evaluated by a chest physician or thoracic surgeon.

Diagnostic methods

When a suspicious finding is detected, the aims are to confirm the diagnosis, to determine the type and molecular characteristics of the tumor, and to establish accurately how far the disease has spread (its stage).

• Computed tomography (CT): Shows the size and location of a lung nodule or mass and its relationship to neighboring structures. It is the basic tool for evaluating the chest and upper abdomen.
• PET-CT: Shows the metabolic activity of tissues and plays an important role in staging by assessing lymph nodes and distant organs. Positive findings are confirmed with a tissue sample when needed.
• Brain MRI (or contrast-enhanced CT): Used to look for brain metastases, particularly when advanced disease is suspected and in selected patients before surgery.
• Bronchoscopy: Examination of the inside of the airways with a thin, flexible optical instrument, with samples taken by biopsy, brushing or washing. It is performed under sedation or anesthesia.
• EBUS (endobronchial ultrasound) and mediastinoscopy: Used to sample the lymph nodes in the mediastinum, the area between the lungs. EBUS uses an ultrasound probe on the tip of the bronchoscope to take needle samples from lymph nodes in a minimally invasive way. When necessary, mediastinoscopy (sampling lymph nodes through a small incision at the base of the neck) is performed.
• CT-guided needle biopsy: When a lesion in the outer part of the lung cannot be reached by bronchoscopy, a sample is taken with a thin needle through the chest wall.
• Surgical biopsy: In selected lesions that cannot be diagnosed by the methods above, or that are going to be removed anyway, diagnosis and treatment can be planned in a single procedure using minimally invasive (VATS or robotic) techniques.
• Pathology and molecular/biomarker testing: The type of cancer is determined on the sample. In non-small cell lung cancer, particularly adenocarcinoma, genetic changes such as EGFR, ALK, ROS1, BRAF, KRAS, MET, RET and NTRK are tested for, together with PD-L1 expression in the tumor. These results directly influence the choice of targeted therapy or immunotherapy.
• Pulmonary function tests and heart assessment: Performed to determine whether the patient can tolerate surgery or other treatments and how much lung tissue can safely be removed. Chronological age alone does not decide whether surgery is possible; what matters is the patient's general condition and heart and lung reserve.

Types of lung cancer

Under the microscope, lung cancers fall into two main groups:

• Non-small cell lung cancer (NSCLC): Accounts for the large majority of cases. Its main subtypes are adenocarcinoma, squamous cell carcinoma and large cell carcinoma. Adenocarcinoma is currently the most common subtype.
• Small cell lung cancer (SCLC): Tends to grow faster and spread earlier, and is very strongly linked to smoking. Treatment is mainly based on chemotherapy, radiotherapy and immunotherapy. Surgical resection can rarely be considered only in carefully selected patients with very early-stage disease and no lymph node involvement, and it is usually followed by chemotherapy.

There are also rarer lung tumors, such as carcinoid tumors. Benign tumors and nodules can occur in the lung as well, so not every lung nodule means cancer, but each one needs to be followed up or investigated.

Staging (TNM system)

Staging describes how far the disease has spread and is one of the most important factors in choosing treatment. The internationally accepted TNM system (currently in its 9th edition) has three components:

• T (tumor): The size of the tumor and its extension into surrounding structures
• N (lymph nodes): Whether the cancer has spread to regional lymph nodes and to which lymph node stations
• M (metastasis): Whether the cancer has spread to distant organs (such as the brain, bones, liver, adrenal gland or the opposite lung)

These findings are combined to divide the disease into four stages:

• Stage I: The tumor is small and confined to the lung, with no lymph node involvement.
• Stage II: The tumor may be larger, or it has reached the lymph nodes right next to the lung (hilar nodes).
• Stage III: The tumor has spread more extensively locally, with involvement of the mediastinal lymph nodes or neighboring structures, but without distant organ metastasis.
• Stage IV: The disease has spread to the opposite lung, to the lining of the lung (pleura) or to distant organs.

The clinical stage is determined before treatment from imaging and biopsy results. The final (pathological) stage becomes clear once the tumor and lymph nodes have been removed and examined by the pathologist.

Treatment

The treatment plan is individualized according to the type and stage of the disease, the molecular features of the tumor (a driver mutation, if present, and the PD-L1 level) and the patient's general health. Wherever possible, decisions are made in a multidisciplinary tumor board attended together by thoracic surgery, medical oncology, radiation oncology, pulmonology, pathology and radiology specialists.

Surgery

In early-stage (Stage I-II) and some carefully selected Stage III non-small cell lung cancers, surgery is one of the main treatment options if the patient is fit for an operation. The goal is to remove the tumor completely, together with a margin of healthy tissue (complete resection).

• Lobectomy: Removal of the lung lobe containing the tumor. It is the most commonly performed standard operation.
• Segmentectomy: Removal of only the relevant segment of a lobe, in very small, selected tumors or in patients with limited lung reserve. It preserves more healthy lung tissue.
• Bilobectomy, sleeve (bronchoplastic) resection and pneumonectomy: May be needed depending on where the tumor is located. Whenever possible, techniques that preserve lung tissue (such as sleeve resections) are preferred; removal of an entire lung (pneumonectomy) is performed only when necessary and after careful planning.
• Lymph node dissection or sampling: During the operation, the hilar and mediastinal lymph nodes are also removed and examined. This provides accurate staging and guides the decision on additional treatment.
• Minimally invasive approaches: In suitable patients the operation can be performed through small incisions instead of a large one, using VATS (video-assisted thoracoscopic surgery) or robotic surgery. These techniques generally mean less pain, a shorter hospital stay and faster recovery, while the tumor is removed according to the same oncological principles. The most appropriate approach for each patient is chosen by the surgeon according to the location and size of the tumor.
• Extended operations: If the tumor has grown into neighboring structures such as the chest wall, diaphragm or great vessels, these structures can be removed together with the tumor in selected patients. The true extent of the disease sometimes becomes clear only during the operation.

After surgery, the remaining lung tissue expands to compensate to some degree for the part that was removed, so most patients do not develop severe shortness of breath. Breathing exercises before surgery and quitting smoking improve recovery.

Radiotherapy for patients who cannot have surgery (SBRT)

For patients with an early-stage tumor whose operative risk is high because of heart or lung disease or other health problems, or who decline surgery, stereotactic body radiotherapy (SBRT) is an effective option. In SBRT, a high dose of radiation is delivered with great precision to the tumor, usually in only a few sessions. In suitable patients it provides good local control of the disease, but it is generally not considered a replacement for surgery in patients who are fit for an operation. The choice is made jointly in the tumor board.

Chemotherapy and radiotherapy

Depending on the stage, chemotherapy and radiotherapy are used alone, together (chemoradiotherapy), or to complement surgery. In locally advanced (Stage III) disease that cannot be operated on, concurrent chemoradiotherapy is usually given, and in selected patients this may be followed by a period of immunotherapy. In small cell lung cancer, chemotherapy and radiotherapy form the basis of treatment, and immunotherapy may be added in extensive disease.

Targeted therapy

Some lung cancers carry a specific genetic change (driver mutation) that drives the growth of the cell. Alterations such as EGFR, ALK, ROS1, BRAF, MET, RET and NTRK, as well as KRAS mutations, are now investigated routinely with molecular testing. For a number of these alterations, targeted drugs, such as tyrosine kinase inhibitors taken as tablets, are today part of standard treatment. Targeted drugs are mostly used in advanced disease, and for some mutations they can also be used after surgery (adjuvant setting). Which drug is appropriate is determined only by the specific mutation found in the tumor.

Immunotherapy

Immunotherapy (immune checkpoint inhibitors) consists of drugs that help the body's immune system recognize and attack cancer cells. The PD-L1 level and other features of the tumor are taken into account when deciding whether this treatment is suitable and whether it should be given together with chemotherapy or on its own. Immunotherapy is used as part of treatment both in advanced disease and in selected early and locally advanced disease.

Combination treatments before and after surgery

In selected patients with early and locally advanced disease, systemic treatments are given in addition to surgery:

• Neoadjuvant therapy: Chemotherapy, or chemotherapy combined with immunotherapy, given before surgery. The aim is to shrink the tumor and control microscopic disease.
• Adjuvant therapy: Chemotherapy, immunotherapy or (in patients with a suitable mutation) targeted therapy given after surgery. The aim is to reduce the risk of recurrence.
• Perioperative therapy: Plans that cover both the period before and the period after surgery.

Which plan is used for which patient is decided in the tumor board according to the stage, pathology, PD-L1 and molecular test results, and the patient's general condition.

Lung cancer screening

Because lung cancer usually causes no symptoms in its early stages, annual low-dose computed tomography (LDCT) screening is recommended for people at high risk. Large studies have shown that regular LDCT screening in high-risk people can detect the disease at an earlier stage and can reduce lung cancer deaths. A chest X-ray is not recommended for screening.

National and international guidelines generally define the high-risk group as adults roughly between 50 and 75 years of age with a significant smoking history (heavy smoking over many years) who currently smoke or have quit recently. The exact age range and smoking-history criteria differ between guidelines. The decision to screen should be made together with a physician, weighing the benefits of the test (earlier diagnosis) against its possible harms (false-positive results, additional unnecessary tests, and radiation exposure, although the dose is low). Screening is not a substitute for quitting smoking; people who smoke should also be offered support to quit.

Prevention and quitting smoking

Lung cancer is largely a preventable cancer. The most effective protection is never to use tobacco or to quit. Quitting helps at any age; it improves treatment outcomes and reduces the risk of complications after surgery. Support from a physician, counseling and, when needed, medication increase the chance of success.

• Avoid second-hand smoke in enclosed spaces.
• Consider testing the radon level in your home, and if it is high, take ventilation or remediation measures.
• Use protective equipment against asbestos, silica and chemical dusts and fumes at work.
• Eat a balanced diet rich in vegetables and fruit and stay physically active. Vitamin supplements have not been shown to protect smokers against lung cancer, so quitting smoking, not taking supplements, is what matters.

Follow-up after treatment

After treatment is completed, patients are monitored at regular intervals. Follow-up includes examination, imaging (usually a chest CT) and additional tests when needed; the frequency depends on the stage and the treatment received. The aims are to detect recurrence or a new lung tumor early, to monitor treatment-related side effects, and to support pulmonary rehabilitation and a smoke-free life. If new symptoms such as a cough, blood in the sputum, shortness of breath, pain or weight loss appear, you should see your physician without waiting for the next scheduled visit.

Conclusion

The diagnosis and treatment of lung cancer have advanced considerably in recent years. Accurate diagnosis, correct staging, molecular testing and multidisciplinary evaluation make it possible to build the most suitable plan for each patient. The information on this page is for general information only and does not replace a definitive diagnosis or treatment decision. An individual treatment plan is decided after examination and review of the necessary tests. To make an appointment or ask for information, please reach us through our contact page.