lung cancer causes

                                                 Lung cancer causes  

Lung cancer  

Lung cancer, also known as lung carcinoma, Lung cancer is the uncontrolled growth and division epithelial cells in one or both lungs. Lung cancer cells are tumours like growth that affects the lungs and the other parts of the body like liver, heart, brain, bones etc,

The most worrying thing is that 45% of the cancer type across the world is lung cancer,30% of them are smokers or live with smokers.

Lung cancer is cancer that starts from the lungs. There are two types of cancer in the lung.

1. Non-small cell lung cancer (NSCLC)  

2  Small cell lung cancer (SCLC) 

1. NSCLC: The most common type is non-small cell lung cancer.NSCLC grows up slowly in the body. It is found in about 80 to 85% of people. NSLC  is a heterogeneous group of relatively undifferentiated cancers that share large cells and do not fit into other categories. 

These cells types have rapid doubling times and an aggressive clinical course, They present as central or peripheral masses. Cancers that are not better differentiated on pathologic review other than carcinoma unspecified" makeup about 20-25% of cases.

2, SCLC:   Small cell lung cancer (SCLC) is found in about 15 to 20 per cent of lung cancers.  These small cell lung cancer grows and spreads faster than small cell lung cancer. In some cases, lung cancer contains both non-small cell lung cancer and small cell lung cancer.

Small cell lung cancer  (10-15% of cases) is a tumour of bronchial origin that typically begins centrally, infiltrating submucosally to cause narrowing or obstruction of the bronchus without a discrete luminal mass. 

 Staging 

There are two essential principles of staging NSCLC. First, the more extensive the disease, the worse the prognosis; second, surgical resection offers the best chance to cure. Staging of NSI uses two integrated systems. 

The TNM international staging system attempts a physical description of the neoplasm: 

• T describes the size and location of the primary tumour,
• N describes the presence and location of nodal metastases; and 
• M refers to the presence or absence of distant metastases, 

These TNM stages are grouped into prognostic categories (stages 1-IV) using the results of clinical trials.

  Many patients with stage 1 and stage 2 disease are cured through surgery. If someone is diagnosed with stage 1 lung cancer, a surgery where the doctor removes cancer tissues with little bit healthy tissues.  Patients with stage 3 B and stage IV disease do not benefit from surgery. 

Patients with stage 3B disease have a locally invasive disease that may benefit from surgery in certain circumstances as part of multi-modality therapy.

Symptoms of lung cancer 

Lung cancer doesn't cause any symptoms until it too late to cure. Non-small cell lung cancer and small cell lung cancer have the same signs and symptoms,

Early symptoms may include.

• Chest pain 

• Accumulation of water in the chest

• Fever  

• Face swelling  

• Weight loss  

• Night sweats 

• Change in voice  

• Blood in cough  

• Shortness of breath 

• Accumulation of water in the chest  

• loss of appetite 

Causes of lung cancer 

Some common causes of lung cancer are,

• Smoking tobacco products

• Genetic 

• Air pollution

• Radiation X-ray or CT scan 

Lung cancer is considered to be the most common cancer in the world today, it is also the leading cause of death in the world and the biggest reason for this is the growing trend of smoking in the world today.

Cigarette smoking causes 90% of cases of lung cancer. The causal connection between cigarettes and lung cancer is established not only epidemiologically but also through the identification of carcinogens in tobacco smoke and analysis of the effect of these carcinogens on specific oncogenes expressed in lung cancer.

 Environmental risk factors for the development of lung cancer include exposure to environmental tobacco smoke, radon gas (among uranium miners and in areas where radium in the soil causes significant indoor air contamination), asbestos (60- to 100-fold increased risk in smokers with asbestos exposure), metals (arsenic, chromium, nickel, iron oxide), and industrial carcinogens.

Some common causes of lung cancer are, Smoking tobacco products,  Genetic, Air pollution,  Radiation X-ray or CT scan.

Laboratory investigations

 Lung cancer tumour can be seen on X-ray, CT scan, PET and MRI. All these scans are giving accurate results. 

Thoracentesis (sensitivity 50-65%) can be used to establish a diagnosis of lung cancer in a patient with malignant pleural effusions. 

 Biopsy of the pulmonary parenchyma or peripheral nodules, and FNA biopsy of mediastinal lymph nodes

 Imaging :

Lung cancer can be detected in the early stage with an X-ray, a coin like size and mark on a chest X-ray shows the cancer of the lung. Nearly all patients with lung cancer have abnormal findings on chest radiography or CT scan. These findings are rarely specific for a particular diagnosis.

Screening :

Screening with low-dose helical CT scans has been shown to improve mortality rates for lung cancer. 

The implications of widespread screening of smokers raise issues of false positives (96% in this study), surgical and medical complications from additional testing, risks of cumulative exposure to radiation, and risks of increasing patient anxiety and stress on an already limited pool of resources.

Treatment of lung cancer 

Mostly the lung cancer diagnosis when it is already staging 3 or stage 4. 

Non-Small Cell Lung Carcinoma : 

NSCLC represents about 90% of cancer in the world today, with stage 1 about 70 -80% patients recover. Same stage 2 patients about 40 to 50% recover successfully. The recovery rate of stage 3 and stage 4 patients is decreased. Cure of NSCLC is unlikely without resection.  

Clinical features that preclude complete resection include extrathoracic metastases or a malignant pleural effusion; or tumour involving the heart, pericardium, great vessels, oesophagus, rent laryngeal or phrenic nerves, trachea, main carina, or contralateral mediastinal lymph nodes.

Accordingly, stage I and stage 2 patients are treated with surgical resection where possible. 

Stage 2 cancer is found in the lung and nearby lymph nodes. Stage 2 possibly a subset of stage IB, are recommended to receive adjuvant chemotherapy or radiotherapy or both. 

Stage  3B patients treated with concurrent chemotherapy and radiation therapy have improved survival. 

Stage 4 cancer has spread to both lungs and also spread out around the lungs area or to distant organs. Patients are treated with chemotherapy or symptom-based palliative therapy or both.

Patients with small early stage primary lung cancers who are not candidates for surgery because of significant Comorbidity or other surgical contraindication may be candidates for stereotactic body radiotherapy. 

Stereotactic body radiotherapy, which is composed of multiple non-parallel radiation beams that converge, allows the delivery of a relatively large dose of radiation to a small, well-defined target.

Neoadjuvant chemotherapy consists of giving antineoplastic drugs in advance of surgery or radiation therapy. There is no consensus on the impact of neoadjuvant therapy on survival in stage I and stage 2 NSCLC. 

 Neoadjuvant therapy is more widely used in selected patients with stage 3A or select stage 3B disease.    

Palliative Therapy 

External beam radiation therapy is also used to control dyspnea, hemoptysis, endobronchial obstruction, pain from bony metastases, obstruction from superior vena cava syndrome and symptomatic brain metastases. 

Resection of a solitary brain metastasis improves the quality of life when combined with radiation therapy, and if there is no evidence of other metastatic diseases, it may improve survival.

Chemotherapy drugs are given either in combination or individually. Basically chemotherapy for treating stage 3 or stage 4 patients who can't afford the surgery.

Survival of lung cancer has amazingly increased over the past years because of molecular testing, oral medications and immunotherapy. We can significantly protect ourselves from lung cancer if we avoid smoking.