Cancer is a disease caused by an uncontrolled multiplication of cells. In lung cancer, cells in the lungs start growing abnormally. Lungs are spongy organs located in the chest and are responsible for respiration, or the exchange of oxygen and carbon dioxide between the body and the environment.

Lung cancer is a heterogeneous disease that can be divided into 2 broad types:

• Non-small cell carcinoma: It is the most common type of lung cancer. It is further divided into adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.

• Small cell carcinoma: It is the most rapidly growing type which makes its management very challenging.

Cancer that begins in the lungs is called lung cancer. It starts when abnormal cells grow and multiply in an uncontrolled way.

Symptoms

Like most types of cancer, the symptoms of lung cancer are not apparent in the early phases of the disease. They appear only in advanced stages.

• A persistent cough that does not respond well to conventional treatment

• Blood in sputum /blood during coughing

• Shortness of breath

• Hoarseness (scratchy or husky voice)

• Unexplained weight loss

• Loss of appetite

• Fatigue

• Weakness

• Bone pain

• Headache

Diagnosis

Lung cancer can either be detected during routine screening or when the growing tumor causes noticeable disruption. The diagnostic workup consists of various examinations that provide information on the presence and the extent of the disease.

The first imaging modality employed in the diagnosis of lung cancer is a chest x-ray which may show an abnormal mass or nodule. Following this, computed tomography (CT) or positron emission tomography (PET) may be preferred to obtain further details such as the size, location, and characteristics of the abnormal mass or nodule, as well as any potential spread of cancer to nearby lymph nodes or other organs.

The other diagnostic methods are the examination of the sputum sample and the histopathological examination of the biopsy sample. The sputum sample is evaluated by microscopic examination. In some cases, sputum cytology is sufficient to diagnose cancer but in most cases, a biopsy must be performed to obtain a tissue sample from the suspected areas of the lung and thus confirm the diagnosis. There are various types of biopsies for lung cancer:

• Bronchoscopy: During this procedure, a flexible tube is inserted through the mouth to see the internal lining of the respiratory passages and to collect a tissue sample from the suspected site of the lung for histopathological examination.

• Mediastinoscopy: This involves inserting a thin tube through a small incision at the base of the neck to collect a tissue sample from a space between the lungs as well as the nearby lymph nodes.

• Thoracoscopy: In this procedure, a small incision is made in the chest and a flexible tube with a camera is inserted. It is used to explore and take samples from the area between the lungs and the chest walls.

• Needle biopsy: A needle is inserted into the body and guided by imaging modalities to remove a small sample of lung tissue from the site suspected to have cancer.

The type of biopsy performed depends on the accessibility of the tumor which is dictated by its location. Besides confirming cancer, advanced analysis can be performed on cancer cells obtained by biopsy, which enables the identification of specific mutations in genes, thereby providing essential information for targeted therapy.

Management

The management of lung cancer depends on several factors such as the spread of the disease and the general condition of the patient. If the cancer is confined to the lungs, surgery is often the standard of care. Based on the size and spread of the tumor as well as the patient’s health and the surgeon’s expertise, surgery can be of several types:

• Wedge resection: Removal of only a small, wedge-shaped portion of the lung containing the tumor.

• Segmental resection: Removal of a slightly larger part of the lung.

• Lobectomy: Removal of the lobe of the lung.

• Pneumonectomy: Removal of the entire lung.

Post-surgical radiotherapy and chemotherapy are usually preferred. In cases where cancer has spread beyond the lungs (metastasis), chemotherapy or radiotherapy is given to control the systemic spread of cancer before surgically removing the tumor masses.

The recent rise in targeted therapy and immunotherapy has provided more options for patients who do not respond well to traditional treatments. More research is underway to better target the cancer cells and improve the survival as well as the quality of life of the patients.