OVERVIEW OF NON - SMALL CELL LUNG CANCER

 

INTRODUCTION

Lung Cancer is the leading cause of Cancer related death worldwide, and approximately 85% of cases are related to cigarette smoking. Metastasis, which is common in lung cancer is a multi stage process, involved invasion into blood or lymph, extravasation and growth at a new site. This Blog gives a way to understand what is Non Small Cell Lung Cancer, and its types and stages and How they are treated using the Secondary Metabolites from the living organisms (Particularly and Plants).

ABOUT NSCLC

• NSCLC is the most common type  of lung Cancer. It comprises 80 - 85% of lung Cancer. 
• This NSCLC is a malignant tumour with extremely high Mortality.
• NSCLC, it name implies that the size of the cancer cell is larger than the Small cell Lung cancer cell, by viewed under the microscope.
• NSCLC is the common type of Lung Cancer.
• It stages from 0 - IV. It mean, we can classify the stage of the NSCLC, based on the 
• Because of the larger  in size, it grow and spread slowly compared to the SCLC.
• The most common subtype of NSCLC are: 

a) Lung Adenocarcinoma: This is a slow growing subtype. It often develops in the bronchi or airways of the lungs. 

b) Lung Squamous cell Carcinoma: This is the least common type of NSCLC. It can form in any part of the lung and tends to grow and spread rapidly.  

c) Large cell carcinoma: This  is the most common type of NSCLC. It typically begins in the outer tissues of the lung that secrete substances such as mucus. This type  is more likely to be diagnosed before it spreads. 

HOW THE NSCLC IS CAUSED

Tobacco smoking is the leading cause of cancer - related death in the world, having been associated to approximately 1.2 million death annually, and it is linked 90% of lung cancer cases. We can classify the Causes into 3 forms, Based on How we exposed to them: 

A) USING TOBACCO:

There are approximately more than 500 to 600 substances used in cigarette. When we burned cigarettes, it create more than 6000 chemicals. From those chemicals, 60 to 70 chemicals are known to cause cancer. Those chemical cancer causing substances are derived from various chemical classes such as Polycyclic aromatic hydrocarbons (PAHs), Nitrosamines, Aromatic Amines, phenols, volatile hydrocarbons, etc., Example: Acetone, Nicotine, Tar, Toluene are the example of the chemicals in tobacco smoke. 

B) SECONHAND TOBACCO SMOKE

Non - Smokers can be exposed to second-hand smoke from different sources, such as in the home, the workplace, and outside public building. Side stream smoke and mainstream second - hand smoke are different in their physiochemical Properties. The ration of side stream to mainstream smoke vary largely depending on the constituents of tobacco products from different manufactures. For example, nicotine, NNK, and NNN ratio can be 7.1, 0.40, and 0.43 respectively.    

C) SMOKE LESS TOBACCO

Smokeless tobacco is unburned tobacco, and is also known as chewing tobacco, oral tobacco, split or splitting tobacco, dip and snuff. Users chew or suck the tobacco in their mouth and split out the juice of the tobacco. However, a study by Hecht et.al., (2017) demonstrates that there is similar exposure to the tobacco - specific carcinogen NNK in smokers and smokeless tobacco users. 

MECHANISM OF NSCLC DEVELOPMENT:

EXAMPLE:  HOW NITROSAMINE COMPOUND INDUCING CANCER

Naturally occurring in tobacco smoke is a procarcinogen, an inert form that require metabolic activation to exert its carcinogenic functions. The Cytochrome P450 usually metabolizes carcinogens by converting the chemicals to more potent carcinogens, by activating the NNK (Nitrosamine compounds) into DNA reactive metabolites that can induce the methylation, pyridyloxobutylation and pyridylhdroxybutylation of nucleobases in DNA and form DNA adducts. The Repair mechanism either should repair the DNA adducts or apoptosis, if its fails it leads to Mutation in multiple genes and finally cancer. 

STAGES OF NON SMALL CELL LUNG CANCER

STAGE 0 - Non Invasive pre - cancer found in lining of airways.

 

STAGE 1 -  Invasive tumour hasn't spread to lymph nodes. 

STAGE 2 - Tumour is 3 to 7 cm and has spread to nearby tissues or lymph nodes, but not to distant body parts. 

STAGE 3 - Tumour is 3 to 7 cm and has spread to nearby tissues or lymph nodes, but not to distant body parts. 

STAGE 4 - Cancer has potentially spread outside the lung. 

TREATMENT FOR NON SMALL CELL LUNG CANCER: 

There are two method of Treatments are available for NSCLC. 

LOCAL TREATMENT:

Local treatment which are used to treat a specific tumour or area of the body. Example of the local treatment, like surgery and radiation therapy. 

TARGET THERAPY: 

Target therapy is a type of cancer treatment that uses drug designed to "target" cancer cells without affecting normal cells. Cancer cells typically have changes in their genes that make them different from normal cells. Genes are part of a cell's DNA that tell the cell to do certain things. When a cell has certain gene changes it doesn't behave like a normal cell.  

CONCLUSION: 

This is all about the Non small cell lung Cancer, I hope this will helps you to understand the basic concept of NSCLC, classification, Causes (especially tobacco), Stages and its therapies.