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Overview of Cancer

 

Cancer is a group of over one hundred diseases that evolve over time and demand uncontrolled cell division within the body. While cancer can develop in virtually any body tissue and each form of cancer has its own distinctive characteristics, the fundamental cancer-producing processes in all types of cancer are very comparable. Cancer can start almost anywhere in the human body, which is made up of trillions of cells. Typically, human cells grow and divide to produce new cells, as the body needs them. They die as the cells grow old or get injured, and they take their place in new cells.


However, as cancer grows, the orderly cycle breaks down. Sometimes, as cells are aged or defective, they survive rather than die, and new cells are created in the meantime. Such additional cells now divide and can form tumours without stopping. Many cancers form solid tumours and make up masses of tissues. Blood cancers like leukaemia typically do not develop stable tumours.


Cancerous tumours are malignant, meaning they can spread to or invade surrounding tissues. As these tumours grow, some cancer cells can break up, migrate to distant places in the body via the blood or lymph system and form a new tumour that is far from the original.


By comparison, to malignant tumours, benign cancers do not develop into or invade surrounding tissues. Benign tumours, however, may sometimes be large. Typically, they do not grow back when removed although malignant tumours do occasionally. Like other benign tumours elsewhere in the body, benign brain tumours may be life-threatening.


Over time a malignant tumour develops. This tumour grows as a result of four mutations but can vary with the number of mutations found in other tumour forms. We do not know exactly how many mutations a normal cell requires to become a totally malignant cell, but the number may be less than 10.

 

How Cancer Arises?

 

Cancer is caused by changes in specific genes, the physical units of inheritance that underlie it. Genes are distributed in thin, tightly packed DNA strands known as chromosomes. Cancer is a genetic abnormality-that is, it is caused by gene changes that control how our cells function, mainly how they develop and divide.


Our ancestors can inherit genetic variations, which can cause cancer. They can also occur during a person’s lifetime due to errors that occur as cells divide, or due to DNA damage caused by specific environmental exposures. Cancer threats to the atmosphere include toxins such as chemicals from tobacco smoke and radiation such as ultraviolet sun rays.


Cancer cells generally experience more genetic changes than healthy cells do, such as DNA mutations. Any of these changes may have nothing to do with the cancer; they may be the result of the cancer rather than its origin.

 

Symptoms of cancer

 

Symptoms differ greatly according to cancer form, location, size and duration.


There may be certain cancers for several years without having any symptoms or declining life expectancy. Popular examples are mild, non-aggressive cancers of the prostate and of the breast.


Many cancers may be relatively small and located at one location, but cause pain. Often widespread cancer can lead to marked exhaustion, weakness, lack of appetite and loss of weight.


Some cancers release substances into the blood that can cause symptoms unrelated to the original tumour ‘s location or size. One form of lung cancer , for example, produces chemicals which cause unusual neurological symptoms.

 

Diagnosis of cancer


Your doctor will review your medical history and conduct a detailed physical examination. He or she will inquire about your family history of cancer.


Blood checks and CT scans of the chest, abdomen and pelvic are conducted in the initial step of a medical examination. Subsequent tests can include MRI and PET scans, depending on the outcome.


For confirming the diagnosis and providing details that will guide prognosis and therapy, a biopsy is almost always needed.

 

Cancer Treatment in India 


Most common cancers that affect our country’s population include breast cancer, lung cancer, oral cancer, stomach cancer and cervical cancer.


The different forms of cancers have many similar characteristics. They protect themselves against the immune system. They also reach the lymph and blood systems to move to other parts of the body such as the lungs, liver and bones. Early detection of cancer could help save lives. Many cancer treatment options exist for various forms of the disease. A patient’s treatment plan depends on the type, level, and degree of cancer they encounter. It is not unusual for patients to go through different combinations of treatments.


When detected early, tumours appear to be smaller and are easier to remove surgically or more likely to shrink after chemotherapy or radiation therapy. For example, certain forms of lymphoma and leukaemia may be treated with chemotherapy and radiation, while other tumours, such as breast and colorectal cancers, may be cured with surgery and chemo-radiation.


Enlisted are the currently available cancer treatments in India:

 

  • Surgery: A procedure in which a surgeon extracts tumours from the body.
  • Radiation therapy: Radiotherapy uses large doses of radiation to kill cancer cells and reduce tumours, focusing on the affected areas.
  • Chemotherapy: Medicines are used here to destroy cancer cells.  
  • Immunotherapy: This strengthens the cancer-fighting immune system.
  • Hormone therapy: This is used to kill growing breast and prostate cancers, which feed on hormones to grow.
  • Stem-cell transplants: These treatments recover blood-forming stem cells in patients with large doses of chemotherapy and radiation that have killed theirs.
  • Precision medicine: Doctors use this based on their genetic understanding of the disease.
  • Targeted therapy: This treatment attacks cancer cells that grow and spread using targeted drugs.