Lung cancer is a disease in which the cells of lung tissues grow uncontrollably and form tumours.
Lung cancer is the leading cause of cancer death in both men and women. It occurs most commonly between the ages of 45 and 70. It is becoming a major health problem in India and is now the commonest cancer in males and the second most common cancer in females in this country.
There are two kinds of lung cancer, primary and secondary. Primary lung cancer starts in the lungs. Secondary lung cancer starts somewhere else in the body; cancer cells then spread to the lung which is referred to as a metastasis. Majority of lung cancer are Carcinomas. (A carcinoma is any malignant cancer that arises from lining cells of organs known as epithelial cells). There are two main types of lung carcinoma, categorised by the size and appearance of the malignant cells.
- Non-small cell lung carcinoma (NSCLC): Includes three sub-types
- Squamous cell lung carcinoma (composed of anaplastic small cells)
- Large cell lung carcinoma (composed of large sized cells that are anaplastic in nature and often arise in the bronchi)
- Adenocarcinoma (cancer of the glandular tissue)
- Small cell lung carcinoma (SCLC also called as oat cell carcinoma): Small cell lung cancers are divided into limited stage (confined to one and half of the chest) and extensive stage disease.
Lung Cancer Symptoms
- Chest Pain with deep breathing
- Coughing up blood or bloody mucus
- Shortness of breath
- Swelling in the neck and face
- Weight loss and loss of appetite
- Recurring respiratory infections
- Difficulty in swallowing
Lung Cancer Diagnosis
One of the problems treating lung cancer in India has been a lack of awareness amongst patients and doctors alike and the overwhelming obsession amongst doctors to treat all lung symptoms as tuberculosis. This approach is patently wrong and any refractory lung symptoms should be investigated by oncologists. In most cases, a definite diagnosis should be obtained before starting treatment. There is little role for empirical treatment in chest diseases.
Evaluation Should Include
- Medical history
- Physical examination to find any lung problems or swollen lymph nodes
- Chest X-Ray to detect enlarged lymph nodes in the chest
- Sputum cytology to find abnormal cells that are present in mucus
- CT scan to follow up an abnormal chest x-ray finding
- Bronchoscopy to take a biopsy of cells from airway. Sometimes, specialised surgical techniques like thoracoscopy and mediastinoscopy may be required to establish diagnosis.
- PET-CT to evaluate the possibility of lung cancer
There is some evidence now that screening for lung cancer in high risk groups i.e. smokers and older individuals may detect early lung cancer which can be treated with positive results. Screening is done using low dose CT scanning of the chest.
Lung Cancer Treatment
Surgery: Surgery is the mainstay of treatment in early lung cancer. However, certain investigations are mandatory before surgery. These mainly confirm that the disease is localised and the patients will benefit from surgery.
Positron Emission Tomography (PET) is used to determine whether the disease is localised and amenable to surgery. Mediastinoscopy or thoracoscopy (VATS) may be needed to assess spread to the lymph nodes in the chest. If positive for spread, this may change the management plan.
Procedures include wedge resection (removal of part of a lobe), segmentectomy (removal of an anatomic division of a particular lobe of the lung), lobectomy (one lobe), bilobectomy (two lobes), or pneumonectomy (whole lung). In recent times, it is possible to treat early cancers with key hole surgery using telescopic techniques without making big incisions. This technique is called VATS.
Chemotherapy: Chemotherapy involves using medicines to kill cancer cells. Chemotherapy is the most effective treatment for small cell lung cancer. It can help control the growth and spread of the cancer.
Radiation Therapy: Radiation therapy is used in both non-small cell and small cell lung cancers. It may be given to people who do not want to undergo surgery or whose cancer has spread to nearby structures, such as the lymph nodes. It may only partially shrink the cancer or slow its growth. Combining chemotherapy with radiation therapy improves survival in this group.
Lung Cancer Prognosis
Late lung cancer has a poor prognosis. However, if detected early and treated at an expert centre, it can give excellent results. Early diagnoses improve survival. People with early non-small lung cancer have a 5 year survival of 60 to 70%. If detected late, on average, people with untreated advanced non-small lung cancer survive 6 months. Even with the treatment, people with extensive small lung cancer or advanced non-small lung cancer do especially poorly, with a 5-year survival rate of less than 1%. Early diagnosis is therefore essential.