Cancer is a class of disease in which group of aberrant cells develop uncontrollably by neglecting the ordinary rules of cell division (Hejmadi, 2010). Cancer is noted to ensue in all communities and in all parts of the world. It disturbs animals and also man. In humans, cancer is recognised to have been present in archaic times as well as present-day societies. The type of cancer most common in a society will differ with the age, sex, distribution and race of people in the community (Stephens and Aigner 2009). In developed countries cancer is the cause of about 25-30% of deaths. It is second to cardiovascular disease as a cause of death.
Moreover youthful people in developed nations faces the risk of dying from cancer other than infections like AIDS (Stephens and Aigner 2009). Cancer is the second main cause of death in United States. About one-half of all men and one-third of all women in the US will grow cancer during their lifetimes. Recently, millions of people are living with cancer or have heard cancer (Ikawo, 2013). The aim of this essay is to know the causes and prevention of cancer. Also more emphasis will be based on the incidence of breast cancer in Nigeria community and ways to check the efficiency of different control measures.
2 Classification of Cancer
Cancers are divided into two kinds; firstly by nature of the tissue where the cancer emanates from. Secondly by the primary site in the body where the cancer first started (SEER Training: Cancer Classification). The classification by tissue types includes carcinoma, sarcoma, myeloma, leukaemia and lymphoma (Cashin-Garbutt). The classification by primary site of origin includes breast cancer, lung cancer, prostate cancer, liver cancer and brain cancer (Ikawo, 2013).
The Carcinoma is a class of cancer derived from epithelial cells. It occurs in the internal and external lining of the body. It affects organs or glands such as lungs, breasts, colon and prostrate (SEER Training: Cancer Classification). Sarcoma emanate in supportive tissue or mesenchymal cells e.g. bone, cartilage and muscle (Classification of cancer-cancer treatment and care healthcommunities.com). Leukaemia is a kind of cancer derived from blood cells. It affects the bone marrow which is the location of blood cell formation e.g. acute-myelotic leukaemia common in childhood and chronic myelocytic leukaemia found in adulthood. Lymphoma are cancers that disturbs lymph nodes at exact location like brain, stomach, intestines etc. (Cashin-Garbutt).
2.1 Causes of cancer
Cancer risks are caused by many factors which could be environmental and hereditary. Below are some of the leading factors that influence cancer risks.
Tobacco is the most crucial overall cause of cancer and is avoidable. It is noted as the major the cause of cancer of the bladder, lung, mouth, kidney, larynx, pancreas and perhaps colon. Tobacco smoking add to many cancer death in many countries because of harmful chemical it contains (Ames and Gold 1998).
Again alcoholic beverages contributes to colorectal cancer, breast cancer, and oral and oesophageal cancer. Also results to inflammation, cirrhosis of the liver, and liver cancer (Ames and Gold 1998).
Equally ionizing radiations caused by radon gas and continued vulnerability to ultraviolet radiation of the sun can lead to melanoma and other skin malignancies. Thus radiation treatment given for one type of cancer. For e.g., those people who take in chest radiation treatment for lymphomas may later develop breast cancer (Ikawo, 2013).
Hence viral and bacterial infections is another cause of cancer. Some cancers are caused by infection with disease causing organisms. Well known ones are liver cancers due to Hepatitic B and C infections; cervical cancer due to infections with Human Papilloma Virus (HPV) (Ikawo, 2013).
Other risks factors of cancer include overweight, obesity, physical inactivity, hormonal changes and mutations (Ikawo, 2013).
2.2 Prevention of cancer
Largely 43% of all cancers are preventable using primary, secondary or tertiary measures. Primary part target at phasing out the exposure to risk factors or carcinogens. Secondary ones aims at fresh detection of cancer or screening for pre-cancer stages, while tertiary measures are cure or palliative care given to diagnosed cancer cases to avert complexity and better quality of life (Omolara,2011).
The primary prevention can be done through dietary control, tobacco & alcohol control and vaccination. Dietary control requires increase consumption of fruits and vegetables, while limiting salt, food additives, fat and red meat intake which can be possible factors of prostrate, stomach and breast cancers. The government helps to standardized alcohols by imposing laws on age and high taxes. Anti-smoking campaigns, reducing young people´s access to tobacco and restriction of smoking in work and public places are all carried out. Hence vaccination will prevent viral infection like Hepatitis B which contributes to liver cancer (Omolara, 2011).
However, secondary prevention can be done through screening arrangements with cervical, breast and prostate cancers. For instance the cervical cancer can be screened with Acetic acid (VIA) or Visual Inspection Lugol´s Iodine (VILI). It is economical and is done at community levels at high coverage (Omolara, 2011).
Moreover, tertiary prevention has to do with treatment. Especially cancers of cervix, breast and prostate are possibly curable.
3 Breast cancer in Nigeria
In Nigeria breast cancer is prevalent in women of age 50 years and above. The two leading risk factors for breast cancer are increasing age and female gender. More risk factors comprises early menarche, obesity, lower levels of physical activity, nulliparity, smoking, alcohol and use of hormone replacement therapy. It usually follows breast lump or bloody nipple discharge. Hence screening can be done through breast examination and mammography o women above 40 years if available (Omolara, 2011).
In addition breast cancer cases in developing countries, which Nigeria is one, don´t use the primary and secondary preventive measure. Rather at the serious stage of the disease, when only chemotherapy and palliative care could be administered is the way of prevention. This follows with high death rate (Abiodun et al, 2012).
Furthermore, in the North-Western region of Nigeria, cancer of the breast was second to cervix cancer. It was the leading malignancy among women at University College Hospital (UCH), Ibadan. At the North-Central area, breast cancer constituted 22.41% of new cancer cases registered in 5 years and accounted for 35.41% of all cases in women (Abiodun et al, 2012).
3.1 Materials and methods
Data on both cancer and patients used for this study were collected from Illorin Hospital-based cancer registry over a period of 10 years. It was collected by active search. Origin of information includes pathology laboratories, clinics and wards. The information gotten on both patients and cancer included age, sex, bases of diagnosis, incidence date, topography and morphology. The first step at the registry is to match the incoming data against the register using “Peson Search” in the CanReg 4 software to check if the case has already been registered from another source or match it annually against the register using the index card arranged alphabetically by name to avoid double registration (Abiodun et al, 2012)
3.2 Results and discussion
Over a period of nine years, 1998-2007, 568 new cases of breast cancer were registered at the Ilorin Hospital-based cancer registry. The table below shows the age distribution which ranges from 18-93 years. The youngest patient in this study was 18 years old girl, the oldest was 93 years, while the highest age of incidence was the 5th decade (40-49 years) which accounted for more than 27.46% (156).
The occurrence of breast cancer in male was low and prevalent at somewhat older age group. Breast cancer and other cancers are preventable if diagnosed early. But in Nigeria and other developing countries, cases are conferred at belated phase of the condition.
AGES NUMBER OF CASES/CANCER C50 BREAST %
0-14 0 0
15-19 2 0.35
20-24 13 2.29
25-29 20 3.52
30-34 44 7.75
35-39 69 12.15
40-44 82 14.44
45-49 74 13.03
50-55 68 11.97
55-59 54 9.51
6o-64 52 9.15
65+ 78 13.73
Unknown 12 2.11
Total 568 100
Figure 1: DISTRIBUTION OF BREAST CANCER BY AGE AT ILORIN CANCER REGISTRY (1998-2008)
(Abiodun et al, 2012)
This study has presented a framework for understanding the causes and prevention of cancer. Cancer as a class of disease is very lethal. But some active measures can be taken to decrease the incidence of cancer. Thus, cancer is largely preventable disease. Greater than 30% of cancer is preventable via avoiding risk factors such as tobacco use, overweight or obesity, low fruit and vegetable intake, air pollution and physical inactivity.
Finally, available data from hospital based of cancer registry in Nigeria shows that cancer incidence is rising. The government should play a pivotal role by collaborating with the people, NGO and International health agencies in order to end the cancer mortality.
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