Cancer is a disease which can affect any organ of the human  body including eyes.There are more than hundred different types of cancerous diseases.The causes ,symptoms and the method of treatment is unique to each type of Cancer .Among many types of Cancers , some are more common than others.

How does Cancer develop and spread :We all know that the human body is made up of cells and they divide and multiply according to the need of the body.But,when the cells multiply when there is no need,a mass of growth of cells occur which is also called a tumor.

Tumors may be benign or malignant.Benign tumors are non-cancerous where as malignant tumors are cancerous.Benign tumors can be removed easily as they do not spread to other parts of the body.The malignant tumors have the capacity to spread to nearby tissues and organs thus making them cancerous.

Spread of Cancer to other parts of the body :The cancerous cells either invade the neighboring tissues and organs or sometimes  may also break free from the primary site and gets transported to other organs through the blood stream.This process is called metastasis.

Though Cancer metastasizes and affects other areas of the body,the disease is still referred to the organ of origination.Almost all Cancers develop and spread through an organ,blood cancer like leukemia affect the blood and the organs that form blood like the bone marrow  and later invade the nearby tissues.

Symptoms of Cancer :  They very with the type of Cancer.The common symptoms are :

* Drastic weight loss

* Fatigue

* Fever.

Since these symptoms are more likely related to other less serious illnesses,it is very difficult to detect Cancer through these symptoms.

Treatment of Cancer: Cancer can be treated in four standard methods.They are surgery,radiation therapy,chemo therapy and immuno therapy.The treatment is based on the type of Cancer,its spread,its stage,the age of the patient and his general health.

Prevention of Cancer :In most cases Cancer is preventable.The first step in Cancer prevention is to know what causes Cancer and risk factors involved.Many Cancer risk factors can be avoided, thus reducing the likelihood of developing Cancer.Some Cancer are hereditary and gene based which cannot be avoided.

The most significant Cancer risk factors are Smoking and Alcoholism.It is never too late to quit Smoking.