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In Southeast Asia, cancers of the
liver, esophagus, nasopharynx, oropharynx, stomach and lung are among the most
prominent in men, although their rank order of frequency may vary from one
geographic region to another. A low incidence of lung cancer, colorectal and
prostatic cancers is characteristic for developing countries.
Global Variation In Cancer Survival
A recent study by IARC provided for the first time systematic, population based
information on survival in developing countries as compared to that of developed
countries, especially Europe and the US (Sankaranarayanan, 1996). It appears
that for tumors associated with poor prognosis (stomach, pancreas, and lung),
the absolute differences in survival between developed and developing countries
were slight. There were greater absolute differences for tumors of the large
bowel, breast and cervix, all of which are associated with a moderate to good
prognosis if detected and treated early and adequately. For all the tumors in
this second group, patient survival was greater in the US than in Europe, at
least in the 1970s to early 1980s the only period for which comparable data were
available. There were also substantial variations among the developing countries
themselves most notably for the carcinoma of the breast and cervix. Finally, the
greatest differences in survival between the US and developing countries were
found for testicular tumors and Hodgkin’s disease.
WESTERN CANCER PROBLEM
The USA is a vast country of about 255 millions, with urban population
contributing 75%. The population age structure is predominantly adults and
elderly. With urbanization and increase of income, the individuals acquire
western dietary habits and life style. The diet is rich in fat and protein
deficient in vegetable and fruits. Smoking tobacco and alcohol drinking are
prevalent habits. This is reflected in the spectrum of cancer.
In the US one in three people will be diagnosed with cancer during their
lifetime, and every minute a person dies from cancer. It is estimated that
within five years cancer will surpass heart disease as the leading cause of
death.
Recent epidemiological trends showed that age adjusted incidence rates for all
cancers combined increased by 18.6% among men, and 12.4% among women, from 1975
-1979 to 1987-1991. This increase was due mainly to the rising rates of prostate
cancer in men and breast and lung cancer in women. The five leading cancers in
USA among men are prostate (43%) lung and bronchus (13%) colon and rectum (8%) ,
urinary bladder (5%) and non Hodgkin lymphoma (4%) whereas among women the
leading five cancers are breast (30%) lung and bronchus (13%) colon and rectum
(11%) uterus(6%) and non-Hodgkin’s lymphoma (4%).
The increased incidence of many cancers is explained by known epidemiological
factors such as an improved detection of early prostate and breast cancers,
cigarette smoking among women, HIV infection in young and middle aged men and
sunlight exposure patterns. In general colon cancer is relatively more common in
economically advantaged populations exhibiting westernized life style practices
and is positively correlated with increased incidence rates for breast and
prostatic cancers (Magrath, 1993).
THE REGIONAL CANCER PROBLEM
The Arab world includes 21 countries with a total population of about 236
million. The urban/rural population split is about 49.7 / 50.3 %. The Arab world
has the following common epidemiological features which contribute to the
profile of cancer problem: (1) high incidence of infection and malnutrition (2)
young age of the population (3) increasing industrialization and urbanization
unaccompanied by protective measures (4) high solar exposure (5) inadequate
public education leading to late presentation of cases.
The profile of cancer among Arab population is characterized by : high frequency
of breast, bladder, lymphoma, nasopharynx, esophagus, larynx, oral cavity and
liver cancer and a low frequency of the prostate lung and colorectal cancer.
Relatively high frequency figures of lung cancer were reported only from Kuwait
and Palestine (14% and 15% respectively).
Breast cancer in the most common malignant tumor affecting Arab females with a
relative frequency of 34% in Egyptian and Palestinian females and about 20% in
reports from Tunisia and Saudi Arabia.
Bladder cancer is frequent where shistosoma haematobium is endemic, namely
Egypt, Iraq, Sudan, Southern Saudi Arabia (Jizan region) and Yemen. The relative
frequency of bladder cancer is about 20% in Egypt, 10% in Iraq and 6% in Jizan
region.
Malignant lymphoma is a relatively common malignancy with reported frequency of
14% in Saudi Arabia and about 10% in Egypt, Iraq and Palestine, There is also a
high frequency of gastrointestinal localization of non-Hodgkin’s lymphoma,
Immunoproliferative small intestinal disease (IPSID) is a rare type of small
intestinal lymphoma first reported from several countries of the region
specially, Gaza and Tunisia.
Nasopharyngeal carcinoma is frequent in Tunisia contributing about 12% of male
cancers and 5% of female cancers as well as Morocco (about 9% of all cancers).
This is probably related to EBV infection.
Esophageal carcinoma is relatively common in Saudi Arabia (5%) particularly in
Qassim area. This is etiologically linked to consumption of thermally hot food
or water contamination with petroleum oil or nitrites.
Oral cancer is relatively frequent in Saudi Arabia (5%) Particularly Jizan area.
This is related to chewing tobacco mixture (Shamma). Liver cancer is relatively
common in Sudan (5%) probably related to high prevalence of viral hepatitis.
THE NATIONAL CANCER PROBLEM (Egypt)
Incidence Profile
In Egypt the mean age of cancer patients is 48 years, two decades younger than
the mean age of American cancer patients.
This is a reflection of the young age structure of the Egyptian population, with
about 50% below the age of 20% years. A comparison of the age distribution of
cancer patients in Egypt and USA is presented in (Table2)
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