a health problem or disease to explore in detail by using a descriptive epidemiologic approach

Descriptive Epidemiology on cancer
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Descriptive epidemiology is an approach that normally analyzes a health problem or disease pattern by summarizing conditions based on persons, place and time. However, the activity of analyzing is conducted through data collection whereby the epidemiologists are able to comprehend the health status of a given population. Therefore, a hypothesis about the causes of the disease or disorder is generated that inform the relevant bodies which involves planning and evaluation. However, this research paper develops an insight on the descriptive epidemiology of cancer disease which its chronic conditions have an impact in the population in terms of its acute social and economic effects. Cancer is a chronic disease which is a global burden that currently records the highest morbidity and mortality rate across developed and developing countries.
Nature of the cancer disease
Cancer is not just one disease, but it is a used to refer to many diseases that are related. Therefore, in all type of cancers, they occur when a mutation causes some body’s cells to be abnormal and begin to divide uncontrollably and spreading in the surrounding body tissues. Basically, cancer is normally considered as a disease of genes which are found in the DNA a body’s cell hence these genes carries the transporters of the proteins that provides the whole body with the energy to function. The alteration of DNA disrupts the function of the genes eventually leading them to produce proteins that are considered to be faulty and, as a result, cells start becoming abnormal by losing its normal growth.

Moreover, the body of a human being normally undergoes a process of cell growth, death and replacement respectively, therefore, the cells that get old or become worn out, they are replaced by new cells. When cancer develops the case becomes different because the old cells which are damaged survive while they should get worn out completely while the new cells continue being produced yet they are not needed. As results, tumors are formed through from uncontrollable growth of these cells hence they spread to other body tissues. (“National Cancer Institute”)
Collectively, research shows that there are more than 100 types of cancers. However, they are normally classified or named according to the organs or tissues they normally affect. The common types of cancer are the bladder, breast, colorectal, kidney cancer, Leukemia, lung cancer, lymphoma, pancreatic, prostate, skin, thyroid and uterine cancers (“National Cancer Institute”). On the other hand, there are some categories of cancer that forms in a specific type of cells. These are the carcinomas which are formed in epithelial cells which cover the external and internal of skin, sarcoma cancer which forms in the bone, soft tissues, muscles, and blood vessel, fat and lymph vessels. Leukemia is a cancer that forms in blood tissues that are found in bone marrows while lymphoma begins forms in the lymphocytes which are the white blood cells that fight diseases. Multiple myeloma begins in the plasma cells while the Melanoma cancer forms in the skin whereby it begins in the cells that makes melanin which gives skin its color. (“National Cancer Institute”)
Cancer cells are normally different from normal cells because they are less specialized compared to normal cells. Basically, normal cells have specific functions whereas they mature into distinct cell type while the cancer cells do not. Therefore, they have the ability to keep multiplying in the body as they ignore the programmed cell death process. The unneeded cells that have been multiplied forms tumor which is fed by the cancer cells through the ability of influencing the normal cells and blood vessels that surrounds them. In addition, they have the ability to evade the immune system and specialized cells that protect the body. Research shows that tumors can take advantage of the immune system to continue growing. As earlier mentioned, cancer is a genetic disease whereby its drivers occurs when the genetic change affects some specific type of genes which are the proto-oncogenes, tumor suppressor genes and DNA repair genes. However, when these genes are altered, they contribute to causing cancer and thus allowing more cells to and ignoring the signal of making them to divide and die but rather they enable them to continue growing and spreading. (“National Cancer Institute”)
However, cancer cells have the ability to spread from the first place they started to another place, a process called metastatic. Basically, metastatic cancer is considered to remain the same type of cancer cells. For instance, when a lung cancer moves to the brain, it still remains to be a metastatic lung cancer. On the other hand, scientific research reports that symptoms of cancer can be noted at the early stage. However, most of the cancer symptoms vary depending with the specific place the cancer is located and where it has spread. Therefore, some cancer tumors can be felt while others can be seen for instance the cancer of the skin can be seen as it occurs on the surface of the skin while lump on the lymph nodes, breast or testicals can be an indication of cancer on those regions. (“National Cancer Institute”)
On the other hand, doctors may find out the level of cancer in a patient’s body and where it is located through staging. This process helps doctors to use the information in planning treatment and predicting person’s outlook. In addition, they normally use staging to determine cancer’s extent in the body. Tumors are being checked all over the body to determine their size or location whereby staging is aided by the use of different techniques such as tests and physical examinations. There are two main types of staging. However, clinical staging involves determining the extent of cancer by estimating through physical examination and tests. This stage determines the best treatment to use and also is used as a tool to make the comparison on how the body is responding to treatment. The second staging type which is pathological staging is normally used after surgery is done sand relies on the results of the exams and tests initially done. (“National Cancer Institute”)
Extent of the cancer disease
According to world cancer report, it was estimated that in the next five years cancer’s incidence rates would gradually increase by 50% and reach 15 million new cases in 2020 worldwide. For instance, in 2000 estimated 56 million deaths were reported from all cancer diseases worldwide, whereas 12% of the total number was caused by malignant tumors. In the same particular year, it was reported that malignant tumor caused the death of estimated 5.3 million men and estimated 4.7 million women worldwide, therefore, concluding that cancer is a global burden, particularly in developing countries. Use of tobacco and diet are reported to be the major causes of cancer globally, especially in developing countries. Reduction of tobacco consumption would greatly stem out the increase of cancer abased on the factual data of approximately 100 million people died in 20th as a result of diseases related to tobacco consumption. Therefore, the predicted increase in cancer incidence that is projected to reach 15 million would be influenced by the growing adoption of the unhealthy lifestyle that is influenced by technology, current habitual trends such as smoking prevalence and steadily ageing populations in both developed and developing countries. (“WHO | Global cancer rates could increase by 50% to 15 million by 2020,”)
In Australia, it is reported that indigenous people are likely to die of cancer than other Australians since they likely receive less treatment. However, their cancer diagnosis is caused by risk factors such as consumption of tobacco and it occurs at a later stage. It was reported that in 2005-06 the male indigenous who were hospitalized due to cancer were 1423 and 2109 indigenous females. In 2000-2004, the male indigenous people were reported to be diagnosed with lung, bronchus and trachea cancer were 19% of the total data collected of the diagnosed people. Basically, the major cause of indigenous mortality in Australia is cancer. (Stumpers S, Thomson N, 2009)
Significance of descriptive epidemiology on cancer diseases
As earlier mention, a descriptive epidemiology study is an approach that its focus would concern identifying and analyzing the distribution of a certain disease or health problem in populations whereas in this case the disease to be analyzed is cancer. According to epidemiology, cancer disease spread according to factors such as age, sex, race, marital status, socioeconomic factors, time and geographic areas. However, this study will involve describing cancer patterns among populations by use of rate measures that will analyze its frequency. The trend of cancer risks prevailing in different population globally will be established by the prevalence, incidence, morbidity and mortality rates, therefore, this will permit comparing different groups within the population. On the other hand, this descriptive study of cancer rates and occurrence in populations will be of great value in developing an etiological hypothesis at the end of this research whereas it will provide the basis of the analytical study. Moreover, the purpose of the analytical study would be necessary to ensure that cancer risks are associated with particular exposures surveyed.
On the other hand, descriptive epidemiological approach considers identifying the causes of cancer and incidences in different types of populations in regard to different geographical locations. In addition, preventive measures of cancer risks will be identified and the methods to enact it in order to stem down the increase of cancer rates. (Cohrssen, Covello, & Council on Environmental Quality (U.S.), 1989)
Morbidity and mortality of cancer
Cancer is considered as a major burden worldwide being ranked as the second cause of death in most countries.
Definitions according to GLOBOCAN
“Incidence is referred as the number of new cases occurring, expressed as an absolute number of cases per year or as a rate per 100,000 persons per year.”(Bray et al.,2005)
“Mortality is the number of deaths occurring, and the mortality rate is the number of deaths per 100,000 persons per year.” (Bray et al.,2005)
“Prevalence describes the number of persons alive at a particular point in time with the disease of interest.”(Bray et al.,2005)
. Based on the world cancer report, it reports that 10.1 million new cases were estimated, 6.2 million deaths and 22.4 million people diagnosed with cancer in the year 2000 whereas this report was based on the recent incidence and mortality data available during that particular time. It was noted that there was an increase in the incidence of approximately 19 % and 18 % in mortality since 1990. (Bernard W. Stewart Paul Kleihues, 2003)
According to Bray et al., 2005, it was estimated 10,862,496 new cancer cases in 2002 worldwide. The estimated of male were 5,801,839(53.4%) and estimated females were 5,060,657(46.6%). The cancer distribution it was reported that 45% new cases were diagnosed in Asia, 26% in Europe, 15 % in North America, 7 % in Latin America and 6 % in Africa. Basically, lung cancer is considered to be the most major worldwide whether considering incidence rate which is estimated to be 1.35 million and mortality rate which is estimated to be 1.18 million. The second being breast cancer with estimated incidence rates of 1.15 million. Stomach cancer follows with estimated 934,000 incidences and 700,000 mortality rate. Liver cancer is the fourth most common cancer with estimated 626,000 new cases and 598,000 mortality rate. Colon and rectum ranks more highly in this case with estimated 1.02 million incidences and 529,000 mortality rate. However, lung cancer is the most major among men while prostate cancer is the most common in developed countries. On the other hand, breast and cervix cancer are the most major among women. Finally, the number of the deaths that was estimated to have occurred in 2002 worldwide due to cancer was 6.7 million. Male deaths were estimated to be 2.7 million and female deaths 2.9 million. However, this data was got from GLOBOCAN 2002 source (Bray et al., 2005)
Descriptive epidemiology on data summary of cancer
Based on the GLOBOCAN 2002 database it was considered that the incidence and mortality rate for both male and female increased substantially and dramatically with age. For instance, between the age group of 0-14 years, the annual male cancer new cases was estimated to be “6.45 per 100,000 in Western Africa, 9.07 per 100,000 in Eastern Asia, 14.10 per 100,000 in Western Europe, and 15.12 per 100,000 in North America” (Ma & Yu, 2006). However, people who were aged 65 years, their incidence rates on the same geographic regions were estimated to be 385.44, 1461.59, 2327.87 and 2958.14 per 100,000, respectively. On the other hand, the mortality rate of cancer was recorded highest in Asia in 2002 with an estimated deaths rate of 3,355,928 in total. In addition, this total was attributed by the death rate of males which was estimated to be 1,983,473 and 1,372,455 of females. The second was Europe with estimated rate of 1,701,472 and North America was the third one with estimated rate of 631,971. (Table 3 and 4) (Ma & Yu, 2006)
The geographical attributes of cancer incidence is basically influenced by the socioeconomic and environmental factors among others based on different places worldwide. For instance, there is quite a huge difference in socioeconomic factors in developed and developing countries whereby the later will be able to use screening method to identify some types of cancers such as breast, cervical, prostate and colon cancers whereas in developing countries these facilities are usually uncommon. Arguably, environmental attributes are considered to have less influence on cancer incidence and mortality rate.
According to GLOBOCAN 2002 database, it clearly predicts the time factor of cancer incidence for a period of 8 years. For instance, the estimated change within the 8 years for male cancer incidence is estimated to increase with 20.5 % whereby if all the factors influencing incident rates such as age, population growth and aging of world population remains constant. There were 5,801,839 estimated males individuals diagnosed with cancer in 2002 and the projected number was estimated to be 6,993,778 in 2010. For females, the projected change within the 8 years would be 19% from 5,060,657 in 2002 to 6,037,753 in 2010. (Table 4) (Ma & Yu, 2006)
Table 3
Age-specific mortality rate of all cancers (except skin) among males in 2002*
0-14 15-44 45-54 55-64 65+ All ages ASR**
Eastern Africa 10.66 59.17 204.22 380.4 736.85 73.9 133.2
Middle Africa 7.11 49.73 198.74 375.94 646.45 65.6 120.8
Northern Africa 7.28 19.81 111.83 293.42 522.28 53.9 83.1
Southern Africa 6.13 38.82 240.95 584.94 951.5 94.5 158.5
Western Africa 4.14 28.02 152.52 244.21 340.43 41.3 73.5
Caribbean 5.98 16.74 120.01 343.39 1229.53 123.8 135.8
Central America 6.06 14.61 75.72 230.21 859.4 63 95.1
South America 6.35 18.4 131.69 369.27 1112.8 101.1 131.8
North America 2.65 16.3 128.69 417.08 1394.91 210.2 153
Eastern Asia 5.05 31.07 229.81 471.03 1198.95 167 161.8
Southeastern Asia 6.87 19.89 147.18 339.23 692.48 73 102.5
South Central Asia 4.3 15.79 113.69 283.14 495.86 55.2 78
Western Asia 7.27 18.86 122.48 379.68 778.81 74.4 108.7
Eastern Europe 5.53 28.64 256.3 750.41 1356.35 253.5 197.2
Northern Europe 3.33 14.52 131.68 413.01 1517.66 269.9 161
Southern Europe 3.47 20.38 175.51 495.03 1447.52 294.4 170.1
Western Europe 3.09 19.58 177.63 483.88 1518.44 294.6 173.9
Australia/New Zealand 3.7 15.37 110.58 378.27 1412.69 213.9 149.1
Melanesia 5.7 24.69 152.6 358.93 667.37 57.3 104.6
Micronesia 7.97 23.48 128.46 323.52 884.31 80.4 114.5
Polynesia 3.45 20.46 203.46 529.58 738.05 86.1 126.3
*Rates are per 100,000 person-years. **Age-standardized rates using the world standard. (Ma & Yu, 2006)

Table 4
Age-specific mortality rate of all cancers (except skin) among females in 2002*
0-14 15-44 45-54 55-64 65+ All ages ASR**
Eastern Africa 7.15 60.04 256.42 408.34 482.72 75 122.7
Middle Africa 5.04 52.21 213.85 313.89 375.8 61.5 99
Northern Africa 5.27 29.24 135.05 208.92 276.45 50.2 65.1
Southern Africa 4.67 40.94 219.9 364.99 483.42 81.1 106.3
Western Africa 3.3 41.77 198.17 264.1 253.65 50.2 79.7
Caribbean 5.01 26.66 140.65 269.81 690.16 100.3 98.4
Central America 5.22 20.72 133.72 253.04 630.68 67.9 89.6
South America 5.19 23.87 148.37 285.8 731.22 93.4 102.2
North America 2.32 19.4 124.07 321.35 910.18 185.8 112.1
Eastern Asia 3.74 20.79 134.74 250.45 590.09 100.8 86.3
Southeastern Asia 5.47 24.98 156.44 244.17 385.43 62.5 76.2
South Central Asia 2.79 22.32 151.7 265.77 307.54 55.2 69.9
Western Asia 5.82 21.36 123.79 238.9 432.93 57.7 74
Eastern Europe 4.56 28.97 158.84 326.95 633.93 175.7 101.9
Northern Europe 2.6 20.44 138.34 327.26 958.56 236.9 118.1
Southern Europe 3.04 19.93 119.1 244.68 714.06 189.03 92.2
Western Europe 2.21 20.7 127.62 274.95 864.06 224.9 106.1
Australia/New Zealand 2.67 19.18 116.09 283.8 841.32 167.1 103.4
Melanesia 3.84 37.06 233.53 400.91 424.78 66.5 104.6
Micronesia 4.12 29.33 175.51 261.52 492.51 66.8 88.6
Polynesia 4.81 48.83 268.4 247.04 368.27 79.2 97.6
*Rates are per 100,000 person-years. **Age-standardized rates using the world standard. (Ma & Yu, 2006)
In conclusion, cancer is generally a burden worldwide and it is incidence and mortality is influence by factors attributes of persons, place and time. According to the distribution of cancer in the population, it is considered cancer diseases are common in developed countries because of the lifestyle choice but in developing countries the commonness is low.
References
Bernard W. Stewart Paul Kleihues. (2003). World cancer report. Retrieved from http://www.iarc.fr/en/publications/pdfs-online/wcr/2003/WorldCancerReport.pdf
Cohrssen, J. J., Covello, V. T., & Council on Environmental Quality (U.S.). (1989). Risk analysis: A guide to principles and methods for analyzing health and environmental risks. Washington, D.C.?: Executive Office of the President of the U.S., Council on Environmental Quality.
Jemal, A., & DeSantis, C. (2010). Global Patterns of Cancer Incidence and Mortality Rates and Trends. Cancer Epidemiology Biomarkers & Prevention. doi:10.1158/1055-9965.EPI-10-0437
Parkin, D. M., Bray, F., Ferlay, J., & Pisani, P. (2005). Global Cancer Statistics, 2002. Ca-a Cancer Journal for Clinicians. doi:10.3322/canjclin.55.2.74
Stumpers S, Thomson N (2009). (n.d.). Review of cancer among Indigenous peoples « Reviews « Cancer (CancerInfoNet) « Chronic conditions « Australian Indigenous HealthInfoNet. Retrieved from http://www.healthinfonet.ecu.edu.au/chronic-conditions/cancer/reviews/our-review
WHO | Global cancer rates could increase by 50% to 15 million by 2020. (n.d.). Retrieved from http://www.who.int/mediacentre/news/releases/2003/pr27/en/
Ma, X., & Yu, H. (2006). Global Burden of Cancer. The Yale Journal of Biology and Medicine, 79(3-4), 85–94.
National Cancer Institute. Cancer Staging. 2015. Accessed at www.cancer.gov/cancertopics/factsheet/detection/staging on March 20, 2015.