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Cancer
Introduction
Cancer is uncontrolled growth of a group of cells which invade and destroy
adjacent tissues, and can move to other parts of the body. The abnormal cells are called
malignant cells, cancer cells or tumor cells. There are more than a hundred types of
cancer and their classification is based on the type of cell that was attacked initially.
Uncontrollable division of damaged cells harms the body when lumps or masses of
tissues (tumors) are formed (Anand et al 2097). Tumors affect the normal systems of the
body such as circulatory, digestive and nervous systems, and produces hormones which
alter normal body function. Benign tumors are ones which demonstrate limited
movement and growth. Malignant tumors are the most dangerous and they form when the
following happens: cancer cells move across the body through the blood or lymph
systems and destroy healthy tissue; and when a cell divides and forms blood vessels and
feeds itself through a process known angiogenesis (Kuper et al 460). A tumor can move
successfully to different parts of the body and grow, invade and destroy tissues which are
healthy. The tumor will be said to have metasized. This document will critically evaluate
the symptoms, causes, diagnosis, treatment and prevention of cancer. This paper will
explore the subject matter of cancer, with a close attention levied to malignant tumors

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Symptoms and signs
Symptoms of cancer are different and they depend on the location of cancer, the
size of the tumor and where it has spread. It is possible to see or feel cancer through the
skin. For instance a lump on the testicle or breast may be a sign of cancer in these areas.
It is possible to note skin cancer (melanoma) when a wart or a mole located on the skin
changes. In addition, Kinzler (134) says that some forms of oral cancers can make the
tongue to have white spots or have white patches in the inside sections of the mouth.
Symptoms of brain tumor tend to occur during the early stages of the disease since
crucial cognitive functions will be affected. Cancer of the pancreas is often small for the
symptoms to be realized early.
It is only realized when pain is felt after squeezing the nerves which are close or
affects the functions of the liver. This can make the eyes and skin to turn yellow, a
condition known as jaundice. Moreover, as the tumor continues to grow, symptoms start
to appear since body organs and blood vessels will be pushed by the tumor. For instance,
symptoms relating to the cancer of the colon include diarrhea, constipation and changes
in the size of stool (Mucci 480). Prostate or bladder cancer can affect the functions of
bladder by causing frequent or infrequent urination. Symptoms which can occur include
excessive sweating, fast weight loss, fever, fatigue and anemia.
Brenner et al (470) say that these symptoms are also common in other types of
problems. For instance, hoarseness and coughing may indicate throat or lung cancer, or
any other ailment. After cancer has metastasized, the affected area will produce other
symptoms. Enlarged or swollen lymph nodes can appear early in the disease. However, if
the spread of cancer affects the brain, an individual is likely to experience seizure, vertigo

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and headaches. When the lungs are affected, an individual will cough constantly and
experience shortness of brain. The liver tends to enlarge leading to jaundice while the
bones are likely to be brittle, painful and break easily. Rheingold (213) says that the
symptoms of a metastasis will be determined ultimately by the areas which have been
affected by the spread of cancer.
Classification: Cancer has been classified into five broad categories. First, Carcinomas
are cancers which start in the skin or tissues that cover internal organs. Since they are
derived from epithelial cells, they cover both internal and external body parts such as
breast, lung, prostate and colon. Second, Sarcomas are cancers which start in the bone,
muscle, cartilage, blood vessels, fats or other supportive or connective tissues. (Anand et
al 2098) says that this group of cancer can also be derived from mesenchymal cells.
Third, Lymphomas are cancers which begin in the immune system tissues and nymph
nodes. This group of cancer is derived from hematopoietic cells. Fourth, Leukemia are
cancers which start in the bone marrow and ultimately accumulate in the bloodstream
lastly, Adenomas are cancers which begin in the adrenal gland, pituitary gland, thyroid,
and other glandular tissues.
Diagnosis:
When cancer is diagnosed in its early stages, successful treatment and cure is
greatly improved. Most cancers are recognized when signs and symptoms begin to appear
or after screening (Panno 125). However, these methods still lack an exact diagnosis and
an individual must visit a pathologist who will investigate the symptoms using medical
tests. Such tests include blood tests, endoscopy, X-rays and CT scans. All these are

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imaging tests which detect the location of a tumor and the types of organs which have
been affected.
Pathology: To get a definitive pathology for several types of malignancies, a pathologist
has to carry out histological examination of cancer cells. Surgery or biopsy is used to
obtain tissues. Skin, liver and breast biopsies can be done from a doctor’s office but other
tissues require an operation under anesthesia. Diagnosis of a tissue indicates the nature of
a cell, genetic abnormalities, histological grade and different characteristics of the tumor
(Brenner et al 474). Immunohistochemistry and Cytogenetics are forms of pathological
tests which can also be performed on a tissue.
Causes
Research evidence indicates that 90 to 95 percent cases of cancer are caused by
environmental factors while only 5 to 10 percent is attributed to genetics (Anand et al
2097; World Health Organization). Cancer researchers say that the word environmental
refers to all those causes not related to genetics. Some of the environmental causes which
are commonly attributed to cancer death include tobacco, infections, radiation, stress,
obesity and diet, environmental pollutants and lack of physical activity.
a. Chemicals: Carcinogens are DNA mutations which cause cancer and they are
linked to specific substances which lead to particular types of cancer. For instance,
Samaras (270) says that 90 percent of lung cancer is caused by smoking tobacco.
Smoking is also attributed to the cancer of the stomach, head, bladder, pancreas, kidney,
neck, larynx, esophagus and stomach. Tobacco smoke has more than 50 carcinogens
which includes polycyclic aromatic hydrocarbons and nitrosamines (Mucci 481). One in
every three cancer deaths in developed countries is attributed to tobacco while the rate is

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one in every five across the world. 2-20% of cancer is believed to be related to the
profession of an individual. Across the world, close to 200,000 cancer deaths are reported
and they relate to occupational risk factors (Medical News Today). For instance, inhaling
tobacco smoke and asbestos fibers can cause mesothelioma and lung cancer. Second,
exposure to benzene outs workers at risk of developing leukemia.
b. Diet and exercise: Cancer attributed to obesity, diet and lack of physical
activity is close to 30-35%. Apart from contributing to 14-20% cancer deaths in the U.S.,
HHH says that excessive body weight puts people at risk of developing other forms of
cancer. Physical inactivity puts an individual at risk of cancer not just because of the
body weight but other negative effects on the endocrine and immune system. Foods
which cause cancer include red meat and diets low in fruits, whole grains and vegetables
(Kinzler et al 135). High salt intake can cause gastric cancer, aflatoxin B1 causes liver
cancer, wile Betel chewing is attributed to oral cancer.
c. Infection: Infectious diseases causes close to 18% cancers worldwide. This rate
varies from region to region with Africa recording the highest (25%) and the lowest in
developed countries (10%) (Medical News Today). Viruses are the most common
infectious agents with the ability to cause cancer but parasites and bacteria can also play a
role. Oncovirus are those viruses which can cause cancer. Cancer of the cervix is caused
by human papillomavirus while B-cell lymphoproliferative disease is caused Epstein-
Barr virus. Kaposi's sarcoma herpes virus is responsible for primary effusion lymphomas
while hepatocellular carcinoma is caused by hepatitis B and hepatitis C viruses.
Leukemia is caused Human T-cell leukemia virus-1. Gastric carcinoma is a cancer

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attributed to bacteria infection. Moreover, parasitic infections which can cause cancer
include liver flukes, schistosoma haematobium and Clonorchis sinensis.
d. Radiation: Ionizing and non-ionizing radiation is responsible for 10% of
invasive cancer. Non- melanoma skin cancers are non-invasive and they are caused by
non-ionizing ultraviolet radiation (Samaras 270). Evidence shows that radiation can cause
cancer in all animals and it may take up to forty years to be clinically manifested.
Leukemia which has been induced by radiation takes 2-10 years to be manifested and
statistics show that children and teenagers are twice as like to be affected as adults.
e. Heredity: Several case of cancer is non-hereditary and they are also known
sporadic cancers. Hereditary cancer is attributed to a genetic effect and statistics show
that there is around 0.3% carriers of the genetic mutation (Medical News Today).
Although this is a sizable number in the population, only 3-10% of cancer cases are
attributed to genes. BRCA1 and BRCA2 are the most common types of gene mutations
which can cause ovarian and breast cancer.
f. Other factors: Some factors expose people to cancer through physical effects
on cells instead of chemical effects. Asbestos is a prominent example of mineral fiber
which causes cancer while synthetic fibers include glass and rock wool, wollastonite and
attapulgite (Anand 2099). None fiber material which can cause cancer include nickel and
cobalt. However, it takes several years of exposure for cancer to develop. Another factor
is physical trauma but it is quite rare. However, repeated application of hot objects to the
body for long periods increases the risk of skin cancer.

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Treatment
Treatment of cancer depends on the type and stage of cancer, as well as age,
health and other additional characteristics. Treatment involves a combination of therapies
as well as palliative care and they are classified into surgery, chemotherapy, hormone
therapy, radiation, gene therapy and immunotherapy (Rheingold 112).
a. Surgery: As the oldest form of treatment, surgery is preferred when cancer is
yet to metastasize since it can be removed and the patient cures completely. This
procedure is common in the removal of the breast, testicle or prostate. Cancer cells
cannot be completely removed after metastasis (Kuper et al 460). However, surgery is
important in controlling other symptoms such as spinal cord compression and bowel
obstruction.
b. Radiation: Commonly known as radiotherapy, high-energy rays are focused
on cancer cells to destroy them (Panno 125). Molecule of the cancer cells are destroyed
by the gamma-rays emitted by radium or high-energy x-rays created by a special
machine. With improvement of technology, it is possible to target beams more accurately
and spare healthy tissues.
c. Chemotherapy: Chemicals are utilized in this process so the cell division can
be affected and thus damage DNA or proteins and this kill the cancer cells. Any cell
which is dividing rapidly is targeted by the treatment and not just cancerous cells.
However, while normal cells tend to recover from the damage induced by the chemical,
cancerous cells cannot recover. Chemotherapy is used when cancer has metastasized
since the medicine moves in the whole body (Samaras et al 270). It is a compulsory

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treatment for some form of leukemia and lymphoma and the patient has to rest between
circles to recover. Side effects include hair loss, vomiting, nausea and fatigue
d. Immunotherapy: The goal is to fight the tumor by strengthening the body’s
immune system. Local immunotherapy treats the specific area which has been affected by
causing inflammation and the tumor shrinks. Systematic immunotherapy moves across
the body and the agent is similar to protein interferon which shrinks tumors (Panno 125).
These therapies are still at their initial stages by researchers have recorded success for
instance in antibodies which limit development of breast cancer cells. Another form of
immunotherapy is one marrow transplant since the immune system of the donor will
assist in attacking cancer cells.
e. Hormone therapy: Most cancers have a linkage to different types of cancers
such as prostate and breast cancer. The aim of hormone therapy is to alter production of
hormones to either stop the growth of cancer cells or to kill them (Mucci 480; Meyers
221). Estrogen levels are reduced through breast cancer hormone therapies while
testosterone reduced are reduced through prostate cancer hormone therapies. Lymphoma
and leukemia are also treated using hormone cortisone.
f. Gene therapy: It is aimed at replacing genes which have been damaged so as to
address DNA damage. Physicians replace a damaged gene which stops cells from
dividing with a copy of a functional gene. Other gene therapies aim at killing the DNA of
the cancer cells. This field is still young and is yet to register success.
Prevention:
Bignold (55) says that cancers attributed to particular behaviors can be prevented
easily. For instance, alcohol and tobacco cause different types of cancers and even a

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current user of these products can stop so as to reduce the risk of cancer. Staying in
shade, wearing a hat and shirt and applying sunscreen go along way in preventing skin
cancer. Diets which have low fat and rich in fruits and vegetables also prevent the risk of
cancer:
a. Dietary: An individual should minimize food which contribute to weigh gain,
sugary drink and energy-dense foods. It is important to eat foods of plant origin and
minimize on red meat as well as processed meat (Panno 125). It is important to minimize
alcoholic drinks and smoking behavior and reduce intake of salt and mouldy cereals.
Studies have shown that grilled meat increases the risk of colon, breast, stomach and
pancreatic cancers due to high level of carcinogens.
b. Medication: According to Mucci (480), aspirin minimizes the risk of cancer
death. Moreover, daily use of raloxifene and tamoxifen minimizes occurrence of breast
cancer among high-risk women by close to 50 percent (Meyers 221). The risk of prostate
cancer is reduced by finasteride but this applies mainly to low grade tumors. Vitamins
have not proved to be effective in prevention of cancer. High levels of Vitamin D tend to
increase the risk of cancer. Beta-carotene supplements increases the risk of lung cancer
but by a minimal margin (World Health Organization). Folic acid supplementation can
increase colon polyps and it does not prevent colon cancer.
c. Vaccination: Scientists have developed vaccines which prevent infection by
cancer-causing viruses. Therapeutic vaccines are being developed to increase immune
response against epitopes related to specific cancers (Bignold 54). Human papilloma
virus vaccine reduces the risk of cervical cancer while hepatitis B vaccine protects an
individual from being prevented by hepatitis B thus reducing the risk of liver cancer.

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Work cited
Anand, Preetha, Ajaikumar B. Kunnumakara, Chitra Sundaram, Kuzhuvelil B.
Harikumar, Sheeja T. Tharakan, Oiki S. Lai, Bokyung Sung and Bharat B.
Aggarwal. Cancer is a Preventable Disease that Requires Major Lifestyle
Changes, Journal of Pharmaceutical Research, 2008 Volume 25, Number 9,
2097-2116
Bignold, Leon P. Cancer: Cell Structures, Carcinogens and Genomic Instability. Basel:
Springer, 2006
Brenner, Hermann, Dietrich Rothenbacher and Volker Arndt. "Epidemiology of Stomach
Cancer". Methods in Molecular Biology, Volume 472, II, (2009). 467-477,
Kinzler, Kenneth W and Bert Vogelstein. Introduction: The Genetic Basis of Human
Cancer. New York: McGraw-Hill, 2002.
Kuper H, Adami HO, Boffetta P. "Tobacco Use, Cancer Causation and Public Health
Impact". Journal of internal medicine 251 (6): 455–66.
Medical News Today. What is Cancer? What Causes Cancer. 12 june 2011. 1 July 2011.
http://www.medicalnewstoday.com/info/cancer-oncology/
Meyers, Robert A. Cancer: From Mechanisms to Therapeutic Approaches. London:
Wiley-VCH, 2007
Mucci, LA, Wedren, S, Tamimi, RM, Trichopoulos, D and Adami HO. "The Role of
Gene–Environment Interaction in the Aetiology of Human Cancer: Examples
from Cancers of the Large Bowel, Lung and Breast". J Intern Med (2001); 249:
477–93

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Panno, Joseph Cancer: The Role of Genes, Lifestyle, and Environment. New York:
Infobase Publishing, 2004
Rheingold, Susan, Alfred Neugut and Anna Meadows. "156: Secondary Cancers:
Incidence, Risk Factors, and Management". In Frei, Emil; Kufe, Donald W.;
Holland, James F. Holland-Frei Cancer Medicine (6th ed.). Hamilton, Ont: BC
Decker, 2003
Samaras, Vassilis, Rafailidis, Petros I, Mourtzoukou, Eleni G, Peppas, George and
Falagas, Matthew E. "Chronic Bacterial and Parasitic Infections and Cancer: a
review" (PDF). The Journal of Infection in Developing Countries 4 (5): 267–281
World Health Organization. National Cancer Control Programmes: Policies and
Managerial Guidelines. Geneva: World Health Organization, 2002