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An Overview of Cancer

February 1, 2021

An Overview of Cancer - featured image

What is cancer and how does it begin:

Cancer is an abnormal growth of cells with the potential to invade or spread to other parts of the body. Abnormal cell growth is known as a tumour which could either be cancerous or non-cancerous (benign). A cancerous tumour means that it has the potential to grow and spread to other parts of the body. There are over 100 types of cancer with the four main types being: Carcinomas, Sarcomas, Leukaemia’s and Lymphomas.

Cancer begins when genetic changes interfere with the body’s normal process of cell growth and cell division. Abnormal cells start to grow uncontrollably and could form tumours. As a cancerous tumour grows cancer cells may be carried into other parts of the body through the bloodstream and go to the lungs, liver or brain or through the lymphatic system as well as local spreading to surrounding structures. This may result in growth of tumours within other parts of the body a process known as metastasis.

Cancer cells differ to normal cell in that they continue to divide without stopping, and do not turn into distinct cell types with specific functions as normal cells do. Cancer cells are also able to ignore signals from the body that tell normal cells to stop dividing and undergo a process known as apoptosis or programmed cell death, in which the body would normally get rid of unneeded cells.

Cancer cells can further influence normal cells to form blood vessels that provide the tumor with oxygen and nutrients, enabling its growth.

Causes of cancer:

Cancer is caused by changes or mutations to the DNA within your cells which prevent cell repair. The factors involved may be genetic, environmental, or constitutional characteristics of the individual. There are various risk factors that could increase your risk of cancer such as:

  • Chemical carcinogens such as tobacco smoke and workplace chemicals
  • Lifestyle factors such as an unhealthy diet and lack of exercise
  • Excessive exposure to the sun or ionising radiation
  • Excess Hormones
  • Family history (genetics)
  • Family history (genetics)
  • Advanced Age
  • Immunosuppression (HIV, Diabetes Mellitus)
  • Alcohol
  • Viruses

Signs and Symptoms:

Potential signs and symptoms vary with each cancer and may include unexplained weight loss, unusual bleeding, lumps or tissue masses, changes in bowel movements or bladder functions, skin changes, fatigue, prolonged coughing or shortness of breath and pathological fractures. Signs and symptoms of cancer will vary dependant on which part of the body is affected.


Diagnosing cancer at its earliest stage often provides the best chance for the best treatment response. If you have symptoms that may suggest cancer, consult with your doctor so that they may do an examination which may include a history of your current symptoms and also establish if there is a family history of cancer, and send you for appropriate tests. Such tests could include laboratory tests and imaging tests.


Screening should be done at regular intervals for people who have a family history of having cancer.
Currently screening is available for certain cancers such as breast, colon, cervical, prostate and lung cancer.

Treatment Options:

There are many types of cancer and treatment requires careful consideration of evidence-based options which can include:

  • Surgery – the aim of surgery as a treatment would be to remove the cancer or as much of the cancer as possible.
  • Chemotherapy – chemotherapy uses drugs to kill cancer cells. They come in an oral and intravenous form.
  • Radiation Therapy – with radiation therapy, high doses of radiation are used to kill cancer cells or to shrink tumours.
  • Brachytherapy – The radiation source is placed in close proximity to the tumour.
  • Immunotherapy – immunotherapy can help your body identify the cancer cells as intruders and aids your immune system in fighting the cancer.
  • Targeted drug therapy – this therapy targets the changes in cancer cells surfaces that help them grow, divide and spread and blocks the pathway of growth and thus the tumour growth.
  • Hormone therapy – some cancers are fuelled by your body’s hormones. Hormone therapy slows the growth of breast and prostate cancer hormones that fuel the growth of cancer cells.

Reviewed by Dr Nokwanda Zuma Specialist Clinical Oncologist at Busamed Modderfontein Private Hospital Orthopaedic and Oncology Centre.
Tel: +27 11 458 2041

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