Advanced Pathophysiology – Cancer
Introduction
Cancer is also known as malignant neoplasm in medical terms. Cancer is caused by
unregulated and continued cell growth which divides and grows uncontrollably, and forms
malignant tumors that invade parts of the human body. It spreads to the other parts of the body
via the lymphatic system or the bloodstream. Benign tumors are a type of cancer with limited
growth and doesn’t invade or spread to the nearby tissues or spread to other parts of the body.
Benign tumors grow gradually, their capsule are well-defined, are not invasive, and are
well differentiated, with low mitotic index that don’t metastasize. Benign tumors are named after
the tissues from which they are from that’s from fatty tissues are lipoma, from the brain glioma,
from the muscles leiomyoma and from joints chondroma.
Malignant tumors grow very rapidly, are not encapsulated, are invasive and poorly
differentiated. They spread distantly i.e. metastasis, have a high mitotic index and have ability to
grow immortally. Malignant tumors are also named after the tissues from which they are from.
Epi tumors are equal to carcinomas (adenocarcinoma and the basal cell carcinoma). Malignant
CT tumors are known as sarcomaschondrosarcoma, osteosarcome.
Neoplasisa means new growth and proliferation to form new tissue. They don’t wait for
signs or signals from the body that new tissues are needed i.e. they ignore apoptoic signs. The
numbers of cells are constantly kept because they don’t diet away the stem cell (progenitor cell).
The cancer stem cells are self renewable and multipotent i.e. they can differentiate into
many types of cells with each stem cell resulting in the carriage of that cancer through with every
cell. Tumor markers are a variety of biological substances which are produced by the cancer cells
found on the cell membranes in the plasma. (Pazdur, et al., 2009)
Cancer signs and symptoms.
The location of cancer metastasis determines the symptoms of cancer. When cancer
begins it has no signs as it gathers mass around it and continues to grow or ulcerates. The
symptoms are generally distant effects of the cancer that are not directly related to metastatic
condition. They may include weight loss, fatigue, fever and changes to skin texture.( Kleinsmith,
2006)
Metastasis
Symptoms of metastasis are due to the continued spread of cancer to other different locations in
the body. They include enlarged lymph nodes, hepatomegaly which means enlarged liver or the
splenomegaly, (enlarged spleen). These can be felt in the abdomen or other parts of affected
bones.
Advanced pathophysiology – Cancer.
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Causes
Almost 90% of all causes of cancer are from the environment and only ten percent are inherited
genetically. Major environmental factors that contribute to cancer deaths are food and obesity
(35 %), tobacco (30%), infections (20 %), radiation (non/ionizing, 10%) others though not so
significant are stress related, lack of exercise and environmental pollutants. Cancers are caused
by a multiple of causes and they are not all from the same source. For instance if a smoker
develops cancer, then it’s not definite that he acquired it from tobacco since he’s a smoker but
there’s an equal chance that he may have inherited or acquired it from air pollution or radiation
since everyone has a small chance of acquiring and developing cancer from the environment.
Heredity. (Cancer syndrome).
Most cancers are not hereditary. Cancers that are hereditary are caused by genetic malfunction
causes the defect. Currently less than 0.3 % of the world’s populations are carriers of the gene
that causes cancer that causes about 3-10% of cancer cases worldwide. These syndromes include
specific inherited mutations in particular genes i.e. BRCA1/2 with a rsk of over 75% in breast
and ovarian cancer.
Physical agents
Some physical attributes of certain substances like asbestos, through prolonged exposure to their
naturally occurring fibres emit mesothelioma; a serous cancer membrane usually formed
surrounding the lungs. Others are glass wool, wollastonite, rock wool, attapulgite. Others include
powdered metallic irons like cobalt, nickel and some crystalline silica. These carcinogens must
find their way into the human body through inhalation.( Kleinsmith, 2006)
Hormones
Some hormones encourage the growth of cancer by promoting additional cell proliferation.
Breast cancer, endometrium, prostrate, ovary, testis, thyroid and bone cancer are agents in sex
related cancers. African men have a higher level of testosterone than men from a Europe
countries hence they have higher chances of developing prostate cancer. Asian men have the
lowest level of testosterone which activates the androstanediol.
Obese people have an increased level of hormones related to cancer. Women who take
hormone replacement and enhancement therapy have an increased risk of developing cancers
that are related to these hormones. People who exercise have lower levels of these hormones and
lower risks of acquiring cancer. Osteosarchoma may be promoted and supported by growth
hormones.
Radiation (radiation-induced cancer)
More than 10% of all invasive cancers are associated with radiation exposure; these include the
none/ ionizing radiation and ultraviolet radiation. A large majority of non invasive cancers are
not melanoma skin related cancers that are caused by non-ionizing ultraviolet radiation. Medical
imaging and radon glass are the major sources of ionizing radiation. Some people with certain
nevoid basal cell carcinoma and retinoblast are more likely to develop cancer when exposed to
radiation. Nuclear power plants have very little or no effect cancer.
Dietary (diet and cancer)
While many nutritionists have argued on the reduced risk of developing cancer while on
particular diets, few have been able to prove these facts. The major habits that promote cancer
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are excessive eating habits leading to obesity and alcohol consumption. A diet with low fruits
and vegetables with high red meat may contribute a little to the predisposing factors that cause
cancer. Studies have associated consumption of processed meat to an increased breast cancer,
cancer of the colon and the pancreatic cancer, a condition which could be due to the
contamination of meat cooked at high temperatures with carcinogens.
Dietary recommendations for a healthy living may include fresh vegetables, fruits, whole
grains and avoidance or reduced consumption of red meat and animal fat.
Reference.
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Kleinsmith, L. (2006). Principles of cancer biology . Pearson Benjamin: Cummings.
Mukherjee, S. (2010). The Emperor of All Maladies: A Biography of Cancer . Simon and
Schuster.
Pazdur, R. et al. (2009). Cancer Management: A Multidisciplinary Approach . Cmp
United Business Media. (online at cancernetwork.com)
Tannock, Ian (2005). The basic science of oncology . McGraw-Hill Professional.
Manfred S. (2008). Encyclopedia of Cancer (4 Volume Set). Berlin: Springer. Olson,
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