Cancer Prevention
~ Part I ~
Knowing
how to prevent cancer (along with early detection and treatment) is important
because it really can save lives and reduce suffering from cancer. Cancer
causes one in every seven deaths, worldwide. It is more than HIV and AIDS,
tuberculosis, and malaria combined. Fortunately, about half of cancer cases can
be prevented by the current evidence based guidelines.There are three type of
cancer prevention: primary, secondary, and tertiary prevention.
*
Primary prevention refers to avoiding or eliminating cancer causing substances.
The goal is to prevent the cancer before it begins in the first place. Example:
avoid smoking, vaccination against cancer causing viruses, and elimination of
carcinogens in the workplace. Primary prevention is only possible when the
cause of cancer is known.
*
Secondary prevention refers to early detection and screening. The goal is to
detect premalignant cells before they become cancerous or early stage cancer. Example:
PAP smears test for cervical cancer, mammography for breast cancer, or colonoscopy
for colorectal cancer.
*
Tertiary prevention refers to the treatment of cancer patients. The goal is to
prevent premature death and to maintain quality of life.
The
burden of cancer is great, but it can be prevented. Effort to reduce the burden
of cancer happens on two levels: personal level, and national and community
levels. In the personal level, we as an individual can try to do things that
lower our risk of developing certain cancers.
Here
are several factors we should know to reduce our risk:
1. Tobacco and
cancer
It
is clear that tobacco is the world’s leading cause of cancer and cancer related
deaths. Cigarettes are designed to deliver nicotine, powerful drugs that stimulate
pleasure sensors in the brain. It increases mood in a positive way, it eases
anxiety and makes people feel less depressed. However, these positive affects
are offset significantly by all the harm in tobacco. When people smoke, they
take in more than just nicotine. That smoke is a mix of thousands of compounds,
including more than 70 chemicals that are known as possible human carcinogens. Smoking
increases a risk of a lung cancer on average 5-10 fold (many recent studies
show as much as 20 fold or higher). Men who smoke have a 27 times higher rate
of oral carcinoma than nonsmokers. In addition, smoking raises a person’s risk
of other cancers. As those carcinogens get to the lungs, they go into the bloodstream
and carried throughout the body. Thus, smoking also causes the cancer of
larynx, the voice box, the oral cavity, the esophagus, the stomach, the
pancreas, the bladder, the kidney, the liver, the cervix, also colorectal
cancer and some leukemias.
Quitting
tobacco at any age is a big benefit. Even if you are a cancer patient or you
have some other terminal illness.
2. Alcohol and
cancer
Based
on many research studies, there is a strong link between alcohol drinking and
several types of cancer. People who drink about two drinks or more per day, have
at least two or three times greates risk of developing head and neck cancer,
especially the lips, oral cavity, throat, larynk, compare to the nondrinkers. Moreover,
the risk of these cancers is still greater among those who consume alcohol and
also use tobacco. They work together to cause you more harm because alcohol
itself incrases the absorption of tobacco carcinogens by the body. People who
inherit a deficiency in an enzyme that metabolizes alcohol, also have a higher
risk of alcohol-related esophageal squamous cell carcinoma. Alcohol consumption
is also a cause of liver cancer, correlate with a modest increase in colorectal
cancer, and is a clearly established cause of breast cancer in women. One study
in United Kingdom, called the Million women’s study found that a drink per day
produces about a 12% risk for breast cancer, which means for each drink you
have an additional 12% chance of getting breast cancer. There is some evidence
suggesting that some alcoholic beverages also reduce the risk of heart disease,
try to balance that possible protected effect of alcohol against the increased
risk of cancers. If you drink, drink in moderation and be aware of your risks.
3. Diet and cancer
Although
each individual may have unique health issues regarding diet and nutritions,
some recommendatios are made by the Public health guidelines (meaning that
recommendations regarding diet and nutrition are appropriate for entire
populations). It is clear that one of the keys to orchestrating the anti-cancer
diet is the principle of focusing upon a plant-based diet. Consume a diverse
array of fruits, vegetables, and legumes along with whole grains each day
should be your basic foundation. Diet rich in lipids, particularly saturated
fats are often associated with the risk of several cancers and may promote
cardiovascular diseases. Saturated fats typically come from animal foods
(briefly: meats). Studies do suggest that populations consuming large amount of
red meats experience cancers such as breast, prostate, and colon cancers. Also,
excessive salt intake may have health risks for hypertension and cardiovascular
diseases, as well as some cancers. One of the most common questions regards
what dietary supplements to consume to prevent cancer. The well-done studies on
dietary supplements and cancer risks have does far been unimpressive. At the
present time, a multivitamin and mineral supplement that meets the RDA
(Recommended Dietary Allowance) will likely post little health risk, but
potential benefits for cancer reduction still have not been established.
4. Heredity and
cancers
Cancer
is a genetic disease, but not all cancers are hereditary. Genetic disease means
that cancer is a disease of the genes, caused by changes (known as mutations)
that occur in the genes of the body during human’s lifetime. Hereditary cancer
refers to gene mutations that are passed from one generation to another,
increasing an individual’s risk of developing particular kinds of cancer. The individual
does not inherit a cancer, but they inherit a gene mutation that increases the
risk that they will develop a certain kind of cancer sometime during his or her
life. There are four red flags that signal the possibility that a
cancer-related gene mutation might run in the family.
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First, if the cancers are diagnosed at an early age, usually younger than 50
years old.
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Second, there are multiple cases of cancers on the same side of the family
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Third, if an individual has developed multiple cancers themselves, or cancers
on both sides of their body, for example bilateral breast cancer.
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Fourth, if the cancers are rare. When individuals develop rare tumors, it is
more likely that they might be hereditary.
The
family members most at risk of carrying cancer-related gene are first and
second degree-relatives. First degree relatives are those who share half of
your genes (mother, father, sister, borther, and children). Second degree
relatives are those who share a quarter of your gene (half siblings, aunts,
uncles, nieces, nephews, grandparents, and grandchildren).
The
risk of developing breast cancer and ovarian cancer in women is much greater
for both men and women who inherit a harmful mutation in one or both of genes
called BRCA1 and BRCA2. These mutations can be inherited from either your
mother or father. In the general population, only 1.4% of women will develop
ovarian cancer during their lifetime; however, women with BRCA1 or BRCA2
mutations, the risk is significantly increased between 11 to 39%. Also they
have 65% lifetime risk for breast cancer, significantly higher than 12%
lifetime risk in the general public. Men with BRCA2 mutations also have a
higher risk of breast and prostate cancer. Another example of an inherited gene
mutations that led to cancer is Lynch syndrome. A person is said to have Lynch
syndrome if they have a mutation in one of four genes called MLH1, MSH2, MSH6,
or PMS2. If they have this mutation, they are in 100% lifetime risk of cancers.
They are prone for developing colorectal cancer, followed by uterine, ovarian, and
gastric cancer. All are usually diagnosed before age 50. People with Lynch
syndrome need close cancer surveillance and do annual colonoscopy starting at
age 25.
It
is important to identify people who carry cancer-related gene mutations because
it allows family members to seek counseling and testing. Genetic counseling can
help explain the meaning of the findings and what cancer prevention options are
recommended. This will allow all family members to undergo predictive testing, so
those of the highest risk of cancer can benefit from intensive cancer
surveillance and prevention options. Ultimately, this can save lives.
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Summary
from the lecture “Introduction to the Science of Cancer” – The Ohio State
University Comprehensive Cancer Center-James
Images:
--
Salam
sehat,
Kathryn
- Tokyo
