CANCER by gyvwpsjkko


									                                                                         14 January 2007 No: 04/07



Cancer is a generic term for a group of more than 100 diseases that can affect any part of the
body. Other terms used are malignant tumours and neoplasms. One defining feature of cancer is
the rapid creation of abnormal cells which grow beyond their usual boundaries, and which can
invade adjoining parts of the body and spread to other organs, a process referred to as metastasis.
Metastases are the major cause of death from cancer.

Cancer is a leading cause of death worldwide and the most frequent cancer types are:

           Among men: lung, stomach, liver, colorectal, oesophagus and prostate cancers.

           Among women: breast, lung, stomach, colorectal and cervical cancers.

Quick Cancer Facts

40% of cancer can be prevented (by a healthy diet, physical activity, skin protection against the
sun and not using tobacco).

Tobacco use is the single largest preventable cause of cancer in the world. Tobacco use causes
cancer of the lung, throat, mouth, pancreas, bladder, stomach, liver, kidney and other types;
Environmental tobacco smoke (passive smoking) causes lung cancer.

One-fifth of cancers worldwide are due to chronic infections, mainly from hepatitis B viruses
(causing liver cancer), human papilloma viruses (causing cervix cancer), Helicobacter Pylori
(causing stomach cancer), bilharzia schistosomes (causing bladder cancer), the liver fluke (bile
duct cancer) and human immunodeficiency virus, known as HIV (causing Kaposi sarcoma and

Cancer occurs because of changes of the genes responsible for cell growth and repair. These
changes are the result of the interaction between genetic host factors and external agents, which
can be categorized as follows:

       Physical carcinogens such as ultraviolet and ionizing radiation

       Chemical carcinogens such a asbestos and tobacco smoke

       Biological carcinogens such as infections by virus (Hepatitis B Virus and liver cancer,
       Human Papilloma Virus and cervical cancer), as well as bacteria (Helicobater pylori and
       gastric cancer) and parasites (bilharzia and bladder cancer).

       Contamination of food by mycotoxins such as aflatoxins (products of Aspergillus fungi)
       causing liver cancer.

                           World-Class Clinical Service
                                                                       14 January 2007 No: 04/07

Tobacco use is still the single most important risk factor for cancer and causes a large variety of
cancer types such as lung, larynx, oesophagus, stomach, bladder, oral cavity and others. Although
there are still some open questions, there is sufficient evidence that dietary factors also play an
important role in causing cancer. This applies to obesity as a compound risk factor per se as well
as to the composition of the diet such as lack of fruit and vegetables and high salt intake. Lack of
physical activity has a distinct role as risk factor for cancer. There is solid evidence about alcohol
causing several cancer types such as oesophagus, pharynx, larynx, liver, breast, and other cancer

Cancer arises from one single cell. The transformation from a normal cell into a tumour cell is a
multistage process, typically a progression from a pre-cancerous lesion to malignant tumours. The
development of cancer may be initiated by external agents and inherited genetic factors. Ageing is
another fundamental factor for the development of cancer. The incidence of cancer rises
dramatically with age, most likely due to risk accumulation over the life course combined with the
tendency for cellular repair mechanisms to be less effective as a person grows older.

Cancer control includes the systematic and equitable implementation of evidence-based strategies
for cancer prevention, early detection of cancer and management of patients with cancer.

Up to one third of the cancer burden could be reduced by implementing cancer preventing
strategies which are aimed at reducing the exposure to cancer risk mainly by:

               Changes in tobacco and alcohol use, and dietary and physical activity
               Immunization against Human Papilloma Virus infection
               The control of occupational hazards
               Reducing exposure to sunlight

Another third of the cancer burden could be cured if detected early and treated adequately.

               Early detection of cancer is based on the observation that treatment is more
               effective when cancer is detected earlier. The aim is to detect the cancer when it is
               localized. There are two components of early detection programmes for cancer:

               Education to promote early diagnosis by recognizing early signs of
               cancer such as: lumps, sores, persistent indigestion, persistent coughing, and
               bleeding from the body's orifices; and the importance of seeking prompt medical
               attention for these symptoms.

               Screening is the identification by means of tests of people with early cancer or pre-
               cancer before signs are detectable. Screening tests are available for breast cancer
               (Mammography) and Cervical cancer (Cytology tests).

                            World-Class Clinical Service
                                                                         14 January 2007 No: 04/07

Treatment of cancer is aimed at curing, prolonging life and improving quality of life of patients with
cancer. Some of the most common cancer types such as breast cancer, cervical cancer and
colorectal cancer have a high cure rate when detected early and treated according to best
evidence. The principal methods of treatment are surgery, radiotherapy and chemotherapy.
Fundamental for adequate treatment is an accurate diagnosis by means of investigations involving
imaging technology (ultrasound, endoscopy, radiography) and laboratory (pathology).
Relief from pain and other problems can be achieved in over 90% of all cancer patients by means
of palliative care. Effective strategies exist for the provision of palliative care services for cancer
patients and their families, even in low resource settings.

Enquiries: Directorate Medicine, Telephone 367 9156 or Medical Officers at MH Units

                            World-Class Clinical Service

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