Dhristi NEET 2022-24

About Cancer

One of the deadliest diseases responsible for about 9.5 million lakh deaths in 2018, according to WHO, is cancer. Cancer is a term used to describe a large group of diseases that are characterized by cellular malfunction. Cancer is the deregulation of cell growth. In medical terms, cancer is known as malignant neoplasm; a broad group of diseases involving unregulated cell growth, and the unregulated cell growth forms a "tumour." Cancer can start anywhere in the human body which is made up of a trillion cells.

  

When cells become old or damaged they die and new cells take their place. But when cancer develops, this orderly process breaks down. Old and damaged cells survive when they should die and new cells form when they are not needed. These extra cells can divide without stopping and may form tumours. 


How Does Cancer Develop? 

Cancer is known to be a very dangerous genetic disease because it is caused by mutations in genes that control how our cells work, particularly how they divide and grow. So, errors that occur while cells divide can generate genetic alterations that cause cancer. 


Chemicals and hazardous compounds in the environment, like chemicals in cigarette smoke and ultraviolet raysfrom the sun cause DNA damage that results in cancer. It can also be passed down to us from our parents as a genetic disease. Before the cells that have damaged DNA become malignant, they are eliminated by the body. But with growing age. the ability of the body to do so decreases. This is the reason why cancer is developed later in our life.


A unique set of genetic alterations are there in each person's cancer. As the malignancy progresses, additional alterations occur. Even within the same tumour, distinct cells may have diverse characteristics. Certain changes to genes cause cancer, the basic physical measure of inheritance. 


Causes of Cancer 

Carcinogens like chemicals, tobacco, alcohol, and radiations such as ultraviolet rays coming from the sun are considered the lead causes of cancer.


Types of Cancer 

There are more than a hundred types of cancer. They are usually named for the organs or tissue where the cancer forms. Here are some categories of cancer.

  1. Carcinoma 

It is formed by epithelial cells, cells that cover the inside and outside surface of the body. Carcinoma in different epithelial cells has different names.

  1. Sarcoma 

These are the types of cancer that form in the bone and soft tissues including muscles, fat, lymph, cells, and fibrous tissue. 

  1. Melanoma 

Melanoma cancer begins in the cell that begins with melanocytes. It is considered the most serious type of skin cancer. Melanoma occurs when the pigment cells, which give coloured skin become cancerous.


Diagnosis of Cancer 

The earlier stage of diagnosis in cancer provides the best chance for cure. Doctors may use one or more following approaches to diagnose cancer.

  1. Biopsy 

  2. Radiography technique 

  3. Computed tomography 

  4. Magnetic resonance imaging 

  5. Molecular biology techniques 

  6. Laboratory test 

  7. Physical exam 


Treatment of Cancer 

The type of treatment depends on the type of cancer and how advanced it is. Depending on cancer, a patient can have a combination of treatments such as: 

  • Surgery 

  • Chemotherapy 

  • Radiation therapy 

  • Immunotherapy 

  • Targeted therapy 

Many drugs have side effects in cancer patients like hair loss. So, interferons are injected into cancer patients to develop immunity against these side effects. 


Types of Tumour 

Based on their ability to undergo metastasis, tumours can either be cancerous or non-cancerous and are classified into three types:


Benign Tumour

This type of tumour is localized to a particular location in the body so it doesn't spread to the other body parts, and due to this reason, it is not that harmful. This tumour occurs in regions like the brain, and sometimes they turn fatal also. Surgery is one of the most common treatments to remove benign tumours. 


Malignant Tumour

Malignant tumours are known to be cancerous, which shows that they tend to grow quickly to other tissues of the body. This tumour has high metastasis properties, and it grows frequently into the bloodstream, and from there it can form secondary tumours across different sites in the body part. 


Premalignant Tumors

This tumour is a kind of benign tumour but it shows features of malignant tumours. This tumour has an increased risk of becoming cancer. Benign tumours become premalignant and eventually, malignant.

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FAQs (Frequently Asked Questions)

1. What are the methods of cancer detection? Describe the approaches for the treatment of cancer.

The methods of cancer detection and diagnosis are as follows: 

  • Physical exam (your doctor may feel the area of the body). 

  • Laboratory test (it helps the doctor to examine your bones and organs in a non-invasive way).

  • Techniques like radiography, computed tomography, molecular biology techniques, and MRI (magnetic radiation imaging). 

The common approaches for the treatment of cancer are surgical - which includes removal of tumours and immunotherapy using interferons to boost cancer cell killing.

2. Define the term Metastasis?

The spreading of cancer cells from the site of origin to other parts of the body is termed metastasis. This process mainly occurs in lymph or the bloodstream. During metastasis, the growth of cells occurs rapidly and it damages the normal tissues surrounding the cancerous cells.

3. How does cancer arise?

Cancer is caused by certain changes to genes that control the way our cells function, especially how they grow and divide. Mutation in genes can be caused by accelerating the cell division rates or inhabiting normal control. Sometimes the genes inherited from our parents can cause cancer.

4. What is metastatic cancer?

Cancer cells move out from their original site of formation and develop new tumours in various places of the body during metastasis. Cancer that is spread from its original location to other locations of the body parts is known as metastatic cancer and the process through which cancer cells spread to different parts of the body is known as metastasis. 


When seen from a microscope, the metastatic cancer cells resemble cells from the initial tumour. Furthermore, metastatic cancer cells and cancer cells from the original tumour often share genetic characteristics, such as the presence of certain chromosomal alterations.


Sometimes treatment may help persons with metastatic cancer survive longer in some situations. But in some situations, the basic purpose of metastatic cancer treatment is to reduce cancer progression or reduce the symptoms it causes. There is a significant impact of the body response in metastatic tumours, illness because of metastatic tumour is the reason for maximum deaths of cancer patients.

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