International Biopharmaceutical Association Publication
CANCER-the pervasive killer disease
Kranti Shikha Tripathy
ABSTRACT:
Cancer in its several manifestations remains one of the most dreaded diseases having achieved
the dubious distinction of the second highest killer disease of the world next only to heart
diseae.Prevention, detection and treatment of cancer does not have any fool-proof solution as yet.
The clinical research scientists the world over are constantly striving to achieve significant
breakthrough in preventive as well as curative aspects of this pernicious killer disease
researching and analyzing several parameters of the disease through cutting edge scientific
technologies. Although scientific efforts have borne fruit during the last two decades or so in
reducing cancer cases in some of the developed countries like USA, it still remains an enigma in
the majority population of third world countries who have limited access to these facilities owing
to their low socio-economic standards in the society. It is time that the entire global community
sit together and decide to shun the predominant commercial consideration in clinical research
and focus on the invention of safe therapies to prevent, detect and cure cancer patients which are
effective with either no or minimum adverse side effects and affordable to reach the enormous
nameless unprivileged/underprivileged masses in the human society at large.
INTRODUCTION:
With 10 million new cases surfacing each year, CANCER has been reckoned as the most
devastating disease worldwide next only to heart diseases. The very name “Cancer” literally
sends shivers down the spine especially in third-world countries where even now cancer is
considered equivalent to “Death” that is tantalizingly near. Societies and people with low socio-
economic status have the highest rates of both new cancers and cancer deaths. In USA 1,368,030
new cases of cancer and 563,700 resulting in death has been reported in the year
2004.Approximately 555,550 people in USA are expected to die of cancer every year-an average
of more than 1500 people per day. As the second leading cause of death in USA, cancer accounts
for one in every four deaths every year. Although there has been a welcome lull in increased
mortality in USA since 1992, the ravages continue to be virulent in third-world nations where
there is no sign of reduction in both new cancer cases and cancer deaths.
DEFINITION, TYPES & CAUSES:
Cancer is the disease in which the body’s cells become abnormal and divide without control.
Cancer may invade nearby tissues and may spread through the blood stream and lymphatic
system to other parts of the body making it more full-blown in the process. An early cancer that
has not spread to the neighboring tissues is called “in-situ cancer” and that has spread beyond the
layers of tissue in which it developed and is spreading into the surrounding healthy tissue is
called “invasive or malignant cancer”. The spread of cancer from one part of the body to another
is caused by migration of cancer cells from the original cancer site through blood and lymph
vessels to produce cancer in other tissues and this phenomenon is known as “metastasis”. The
severity of a particular form of cancer is judged on the basis of the resultant survival rate which
is the ratio of a cancer patient’s chance of surviving a given time frame to that of an average
person of the same age and sex in a similar ambience. Another common term which is often
mentioned is “cancer burden” which is the measure of incidences of cancer within the population
and an estimate of the financial, emotional and social impact it creates.
Cancer can affect any part of the body and describing cancer types is equivalent to mentioning
exhaustive details of complicated human anatomy.However,common cancer types include cancer
of bladder,breast,colon& rectal,endometrical,renal,leukemia,lung,melanoma,non-Hodgkin’s
lymphoma,pancreatic,prostrate,skin(non-melanoma),thyroid,anal,aids-related,brain,cervical,
Esophageal,eye,stomach,liver,myeloma,oral,ovarian,penile,stomach,testicular,urethral,uterine,
Vaginal and vulvar.
Cancer can be caused by a number of different factors and may develop over a number of years.
Many of the causes may not be precise and infact seemingly indeterminate. However some
universally recognized causative factors of cancer can be enumerated as follows:
● Tobacco and tobacco products- Eg.smoking causes 30% of all cancers and 87% of lung
cancers .Chewing tobacco products like gutkas and khaini etc. increases risk of mouth cancer.
● Physical inactivity- (Moderate physical exercise at least 30 minutes a day for 5 days a week
reduces cancer risk.Excercising on a regular basis can prevent prostrate,colon,breast,endometrial
and lung cancer)
● Un-holistic life style like having eaten high-fat diet for most part of past life increases risk of
cancer
● Intake of excessive alcohol- Eg.drinking excessive amounts of alcohol increases risk factor for
oral, esophageal, liver, breast, laryngeal, pharyngeal cancers
● Genetic disposition-Certain genetic traits project increased cancer risk of certain categories-
Eg.breast cancer
● Environmental factors-Exposure to certain chemicals, insecticides and radio-active materials-
Eg.exposure to asbestos causes mesothelioma, exposure to radio-active material causes blood
cancer and several other types of cancer
● Unsafe sex-Practicing unsafe sex can increase risk of developing a virus called HPV-a group
of over 100 viruses medically known as papillioma virus which increases risk of cervical, vulvar,
vaginal and penile cancer.
● Exposure to sun- Skin cancer is caused by exposure to UV rays of the sun. A sunburn or a tan
is actually the result of cell damage caused by sun-wearing sunscreen when outdoors and stung
by the sun rays between 10 AM and 2 PM when sun rays are the worst stinging.
SYMPTOMS, DETECTION & PREVENTION:
Although symptoms of different types of cancer widely vary, one needs to be aware of the
overall general symptoms of cancer. The commonly experienced symptoms of most cancer
patients can be summarized as below:
fatigue: This is more common when cancer is in an advanced stage but may also
occur in early stages.
patients.
er at some point.
jaundice, darkening of the skin,
reddening and skin itchiness and abnormal hair growth can indicate certain types of cancer.
Pain: This is normally present when cancer has progressed. However it can be indicative early
on in case of some cancer forms such as bone cancer, lung cancer, skin cancer, bladder cancer,
anal cancer, cervical cancer, endometrial cancer, kidney cancer, stomach
cancer,leukemia,prostrate cancer, colon cancer,lymphoma,pancreatic cancer and penile cancer.
Detection of cancer assumes utmost importance because for many types of cancer, it is easier to
treat and cure if it is detected early. There are many different types of cancer but most cancer
begins with abnormal cells growing out of control forming a lump that is called tumor. The
tumor can continue to grow until it begins to spread to other parts of the body forming
metastasis. If the tumor is found when it is small, curing the cancer can be easy. However the
longer the tumor goes unnoticed the greater the chance that it has spread which makes treatment
more difficult. The use of screening tests to detect cancer early allow patients to obtain more
effective treatment with fewer side effects and treatments can begin before symptoms appear.
Some common screening tests for cancer are enumerated here below:
▲ Mammography: For breast cancer detection
▲ Pap test: For detection of cervical cancer
▲ Fecal occult blood test: For detection of colorectal cancer
▲ Colorectal endoscopy (sigmoidoscopy or colonoscopy): For detection of colorectal cancer
▲ Prostrate-specific antigen test (PSA test): For detection of prostrate cancer
▲ Predictive diagnostic cancer tests: This is a recent addition designed to predict onset of lung
cancer in smokers and breast cancer and cervical cancer in case of women. However these
tests continue to be very expensive-Eg.cost for breast cancer predictive test is about $3500 in
USA.
▲ Screening tests: Depending on the age and risk factors of a patient, physician may begin
screening a patient for certain types of cancer. Screening means looking for cancer before it
causes symptoms.Regular screening is also recommended for high risk individuals.
Though prevention aspects of different types of cancer are not fool-proof, some risk factors can
be controlled. Choosing the right health behavior and active life style including dietary habits
with plenty of fibre,vegetables and fruit servings, balancing calories with physical activity
,keeping away from tobacco products and no or moderate alcoholic intake, avoiding exposure to
radioactive and known carcinogenic substances ,pesticides and chemicals and avoiding long
exposure to hot sun can help prevent development of cancer.
International society for Preventive oncology is the forum of an international membership
committed to the study of interactive etiological factors in cancer development and their impact
on prevention, detection and management of neoplastic diseases (i.e. cancer).
TREATMENT & CLINICAL TRIALS:
Available treatment or therapies for cancer can be described in the following broad heads:
1 .Biological therapy (sometimes called immunotherapy, biotherapy or simply biological
response modified therapy): This uses the body immune system either directly or indirectly to
fight cancer or to reduce the side effects-Eg.monoclonal antibodies .Monoclonal antibodies help
the body’s own immune system to fight cancer or by locating cancer cells to either kill them or
deliver cancer killing substances to them without killing the healthy cells.
2 .Vaccines: This is a form of biological therapy now being studied in laboratories and through
clinical trials to develop vaccines that may help a patient’s immune system recognize cancer
cells and may help the body to reject tumors and prevent cancer from recurring. Many vaccines
are instead of being used in isolation are used in combination with other treatments such as
surgery and chemotherapy.
3 .Adjuvant and Neo-adjuvant Treatment:
Adjuvant application is an additional therapy after standard treatment. This is designed to
prevent recurrence of cancer.
Neo-adjuvant application is an additional therapy used before the standard treatment of cancer
4 .Radiation therapies: This refer to use of high energy radiation from X-ray, gamma ray,
neutrons and other sources to kill cancer cells and shrink tumors. Radiation may come from a
machine outside the body or may come from radioactive material placed in the body in the area
near cancer cells.
5 .Surgical therapy: In early stage of cancer the cancerous tumor is removed by surgical
operation and this is only effective if cancer cells have not spread to the neighboring tissues and
lymph nodes etc.
6 .Chemotherapy: This is the standard treatment with anti cancer drugs already in vogue.
7 .Combination chemotherapy: This refers to the treatment with more than one anticancer drug
already in vogue.
8 .Combination Therapy: This refers to the use of two or more modes of treatment-surgery,
radiotherapy, chemotherapy, immunotherapy etc.
9 .Gene therapy: This is a treatment that alters a gene in the body. This is a recent scientific
breakthrough which aims at improving the body’s natural ability to fight cancer or to make the
cancer cells more receptive to other kinds of therapy.
10 .Alternative therapies: Such as homeo, ayurvedic, yunani, acupressure and acupuncture,
siddha and above all yogic therapy which off late has shown excellent promise in India coupled
with holistic life style and herbal dietary supplements to fight cancer.
Clinical trials are major avenues for discovering, developing new therapies for cancer. Treatment
trials are designed also to test the effectiveness of new drugs, biological agents, techniques or
other applications in people who have been diagnosed with cancer. There are normally four trial
phases involved namely Phase-I to Phase-IV.The first phase is a preliminary one involving a few
subjects/volunteers ending in Ph-IV which establishes long term safety and effectiveness of the
drug under trial involving few hundreds to few thousands of patients/volunteers before the drug
in question is approved for broad and standard commercial use. The different trials can be
summarized as follows:
■ Preventive trials: Cancer preventive trials are designed for people who are at risk of
developing cancer. The trials evaluate safety and effectiveness of various risk reduction
strategies.
■ Screening trials: These trials assess the effectiveness of detecting the earliest stages of cancer
involving laboratory and imaging tests.
■ Diagnostic trials: They are meant to develop better tools for physicians to classify types and
phases of cancer and in managing cases of cancer patients. Genetic tests are being evaluated as
diagnostic tests to further classify cancers.
■ Genetic trials: Actual genetic trials (gene transfers) are few in number but trials are under way
to determine where actual cellular manipulation at the gene level occurs. Genetic research is
critical component of cancer research as it helps researchers understand the causes of cancer and
can lead to developing clinical trials for effective prevention and treatment of different cancer
forms.
It is important to increase awareness of both physicians and patients to participate in clinical
trials for cancer so that we may test new and effective treatment options more rapidly and
broaden the available options to translate into overall strategy to fight this dreadful disease
afflicting large section of mankind particularly the lesser mortals amongst us. A relatively small
percentage of all adult cancer patients (20 years and older) participate in clinical trials and this
figure does not auger well for the larger human good.
SOME INTERESTING RESEARCH-BASED REVEALATIONS:
It may be pertinent to mention a few significant research-based findings about cancer to make
people more aware about cancer and to remove certain common misgivings about it:
♦ Cell phones don’t cause tumors: Research involving almost half a million people has
concluded that there is no link between mobile phone use and cancers of the head and neck.UK
experts said the important study which followed phone users for up to ten years have found out
that using a mobile phone is not linked to a higher risk of brain tumours.The Danish Institute of
Cancer Epidemiology in Copenhagen looked at 420,095 people who used mobile phones
between 1982 and 1995 and were then followed through until 2002 to see if any developed
cancer. Overall they found 14,249 cancer cases were diagnosed in the men and women studied
but there was no suggestion that they were linked to mobile phone use. (Source-Daily Mail News
Paper)
♦ Abortion pill checks breast and ovarian cancer: Scientists used the abortion drug RU-486 to
keep tumors at bay in mice bred with a gene destined to give them breast cancer. No one is
suggesting women use the abortion pill that way. But the provocative experiment helped
illustrate how the notorious breast cancer gene BRCAI does its dirty work by spurring a hormone
called progesterone that RU-486 happens to block. If researchers could create a safe hormone
blocker, it may offer a long awaited alternative for women with a bad gene pre-disposed to breast
cancer and ovarian cancer. (Source-Friday edition of the journal SCIENCE: said Eva Lee of
University of California, Irvine, USA)
♦ Tea is the cuppa that heals : Frank Pajonk from the University of California in Los Angeles
and his colleagues from the University of Freiburg,Germany studied the effects of extracts of
green and black tea on patients who had been treated with radiotherapy and found significant
healing effect on their skin which was discolored by radioactive rays.
♦ Breast cancer under scanner: Screening women less than 50 years old does not significantly
reduce deaths due to breast cancer because of increased radiation exposure and anxiety caused by
false positive results and higher costs of screening program. (Source-British researchers from
London)
RECENT ADVANCES IN CANCER RESEARCH:
Clinical research scientists the world over are constantly at work in finding the possible causes of
cancer, their most effective remedies and with minimal adverse side effects. The main aim is to
target the cancer cells without harming the healthy cells of the body. It will be worthwhile to
mention the underlying principles of a few significant path-breaking researches undertaken in
this direction which are listed here below in brief:
▬ Three-dimensional high-frequency Ultrasound imaging for longitudinal evaluation of liver
metastasis in pre-clinical models
▬ Clinical, epideomiological and pathological studies which mainly use innovative technology
including micro array technology and nano-technology to determine as many parameters of
cancer as possible
▬ Improved suitable bio-assays and better animal models
▬ In vivo models of metastasis including transplantable syngeneic mouse and human-mouse
xenografts genetically engineered mouse and naturally occurring cancers of companion animals
(pet dogs and cats)
▬ Animal-tumor models which correspond to human epidemiologic evidence are useful in
understanding specific aspects of the carcinogenesis process and the interaction of the process
with physical exercise
▬ Nitric oxide mediated regulation of hypoxia induced B16F10 melanoma metastasis: Recent
studies have shown that the hypoxic up-regulation of tumor cell invasiveness and chemo-
resistance is in part due to reduced Nitric oxide (NO) signaling. Using B16F10 mutrine
melanoma cells, it is demonstrated that the increased metastasis potential associated with
exposure to hypoxia is mediated by a reduction in cGMP-dependent NO-signaling.
There are numerous institutes and organizations currently engaged in Cancer Research ,the most
notable amongst them being National Cancer Institute, US National Institute of Health;
Association for International Cancer Research,UK(AICR).
CONCLUSION:
Cancer being the pervasive killer disease the world over claiming extent of human lives next to
the leading killer i.e. heart diseases, needs global attention in finding safe and effective therapy
at affordable prices so that people with lower socio-economic status which forms the majority of
the population in our planet can avail of its benefit. There must be focus on not only innovation
to find out novel effective therapy with minimum side effects but to reduce the cost to be
affordable to the unprivileged masses of humanity particularly those living in impoverished third
world countries. The preventive aspects should gain priority over the curative aspects and ease of
delivery at the grass roots of the society with easy access should be the targeted focus of the
scientific community managing prevention, detection and cure with due recognition of the
quality of life after cancer attacks a victim. More and more people are benefiting from early
detection of cancer and its successful treatment. The medical advances are improving both
quality and length of survival permitting many survivors to full and productive lives at home and
at work. “If there is no research today, tomorrow’s cancer sufferers will be condemned to today’s
treatment”-Derek Napier, Chief executive AICR.
BIBLIOGRAPHY:
1. Celebrity talking dictionary By Anastasia
2 .www.aicr.org.uk
3 .www.familydoctor.org (Cancer: Early detection)
4 .www.cancer.gov
5 .NCI surveillance, epidemiology and end-results program
6 .www.cancer.about.com
7 .www.cancerline.com
8 .Cancer Statistics 2004, American Cancer Society
9 .Oncological Clinical Trials (Clinical Research Associate Program sponsored by Kriger
Research Center, Inc)
10 .American Cancer Society (2001) Cancer facts and figures, Atlanta, GA, USA
11 .Recent advances in Cancer Research by IvanaCrnic& Gerhard Christofor
12 .Modeling metastasis in vivo By Khanna & Kent Hunter
13 .Cancer Cell Biology- By Charles H Graham and others in International Journal of Cancer
published on 7th October, 2003
14 .Physical Activity and Cancer Prevention: Animal tumor models; Medicine & Science in
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15 .www.iarc.fr/WCR