CANCER
Disease information
CANCER
Cancer
.
All cells contain the same
genetic
code that is responsible, depending on the part of it to be expressed, to control the growth and differentiation of different cell types.
Most cells have
a
limited life with
a
cycle where they are generated, grow and die, in contrast to the other as part of the
nervous
system
does not have the capacity to regenerate once they have differentiated. There are
a
series of control mechanisms that allow the orderly growth of the cells to maintain the smooth functioning of all systems that make up our body. Sometimes these mechanisms are incapable of controlling the growth of
a
cell or
a
cell group (clone) beginning to grow uncontrolled manner, resulting in
a
tumor or neoplastic process.
Not all features of neoplasms are malignant, some of them appear as
a
small tumor without clinical impact. The
problem
arises when that group of cells acquires
a
capacity for continued growth and proliferation with loss of cell differentiation (anaplasia) These malignant neoplastic cells can grow and invade adjacent structures unstructured, as well as being able to spread to other areas than the body either by lymphatic and / or hematogenous, producing crops at
a
distance known as metastasis. The
cancer
is
a
malignant neoplasm.
Causes.
When we talk about
cancer
we can not talk about
a
single cause, we believe that the causes are
multiple
and varied with an overlap between all of them, whose final result will be that
a
particular cell group alters its
normal
cycle of growth and is out of control.
Primarily in
cancer
coexist some endogenous factors, determined by
genetic
and other exogenous, mediated by environmental exposures. In some types of malignancies these factors can act in isolation and in others together.
1. Environmental factors. By epidemiological studies have examined the causal relationship between various factors and certain kinds of
tumors
. Some factors are not able by themselves to cause the tumor
but
acting as interveners (cocarcinógenos) Here are the most important:
Snuff:
considered the first carcinogen, linked to cancers of the lung,
esophagus
, mouth,
larynx
and
bladder
. He is credited with responsibility for 35% of all
tumors
in men and 10 - 15% in women. The relationship snuff -
cancer
remains
a
linear progression.
Diet:
There are no definitive epidemiological studies,
but
it is known that
a
diet high in fiber reduces the incidence of colon
cancer
. The ingestion of food contaminated with aflotoxinas is
a
cause of
liver
cancer
.
Alcohol
: is attributed to 3% of deaths from malignant neoplasms. The snuff and
alcohol
enhances its impact.
Sunlight:
the fraction ultraviolet injuries can occur in the
genetic
material of epithelial cells. It is the
primary
risk factor for skin cancers, including melanoma. Primarily affect subjects with light skin and prolonged exposure to the sun.
Ionizing
radiation
: nearly all tissues are susceptible, breaking chemical bonds cell. The tissues are more sensitive
breast
,
thyroid
and bone marrow.
Iatrogenic factors:
it
has
been found carcinogenic capacity of some drugs and hormones. Taking estrogen, for example, appears to increase the risk of endometrial
cancer
.
Microorganisms:
there is an association between
infection
with certain viruses and parasites and the risk of developing
specific
malignancies. Virus
hepatitis
B and
C
= hepatocellular carcinoma. =
Papilloma
virus in
cervical
carcinoma. Epstein - Barr virus = Burkitt
lymphoma
, nasopharyngeal carcinoma.
Reproductive Factors:
nulliparity favors carcinomas of the endometrium,
breast
and ovary, by contrast multiparity encourage promiscuity and
cervical
cancer
.
Chemical factors:
many substances act as carcinogens. It is the classic relationship between asbestos and mesothelioma,
a
type of lung
cancer
.
2.
Genetic
factors. The vital role played by various
genetic
alterations in the oncogenesis is revealed through
a
series of phenomena known as the role of
family
history as
a
risk factor for the
development
of various malignancies, particularly observed in
breast
cancer
and Colorectal, or the association between certain cancers and certain chromosomal abnormalities or defects in the repair mechanisms of
genetic
code.
Regardless of these phenomena observed accepting the existence of factors that act on areas of
genetic
code that control growth and cell cycle, changing it by mutations or inappropriate activations.
Incidence.
The
cancer
incidence is higher in developed countries. In Spain is the second leading cause of death (22% of deaths) The autonomous communities with the lowest mortality rate are Madrid, Castilla - Leon, Castile - La
Mancha
and
Galicia
, on the contrary, Cantabria and Catalonia have the highest figures.
The incidence is higher in males than in females, in humans are mainly due to
tumors
of the
respiratory
(lung and
larynx
) followed by digestive (
stomach
, colon,
esophagus
) women in the highest proportion to
breast
cancer
, followed as the man of the digestive (colon and rectum,
stomach
,
esophagus
) These figures refer to what happens in Spain, since there is great variability, for example, in the
U
. S. lung
cancer
already exceeds that of
breast
cancer
in women.
Regarding the
tumors
that occur in
childhood
, the most
common
are leukemias, followed by
tumors
of the
nervous
system
.
Classification.
Most cancers are classified according to
a
system
called NMT, with three parameters:
T
: parameter indicating length of the tumor.
N:
parameter that indicates whether there is involvement of lymph nodes and to what degree are affected.
M:
indicates the presence or absence of metastasis.
This classification is used to get an idea of what might be the level of outreach and treatment to follow, depending on the chances that the tumor is healing. It is
a
classification that tries to be prognostic and diagnostic.
Not all
tumors
can be classified according to these parameters, as with hematological
tumors
.
Prevention.
The prevention plays an important role in controlling this
disease
. Can be developed at three levels.
1
Primary
prevention: Try to remove the causes that produce the
disease
. It is not possible to do in all types of
cancer
as many of them are unaware of the cause - effect relationship. Due to the large number of epidemiological studies have identified several factors related directly or indirectly with the onset of the
disease
.
Many of these factors are part of our daily lives. In this sense, is basic awareness through education programs that show the need to reduce the consumption of
alcohol
and snuff, changing dietary patterns by reducing fat intake, increasing consumption of fiber, fruit and
vegetables
in the daily food. Another factor that should be controlled is excessive exposure to sunlight and advise the use of protective creams. It also will take the necessary measures to avoid
contact
with physical or chemical carcinogens known, here plays an important role to fulfill the safety standards at work.
2nd Secondary prevention:
It is based on the early detection of the tumor, so the chances of cure are highest. Can be achieved through knowledge on the part of the population through information campaigns of those signs or symptoms that alert on the appearance of the tumor, which is the case of skin
cancer
where growth,
change
of color
bleeding
or emerging from
a
stain on the skin can put us on the trail of
a
melanoma,
a
disease
in its early stages
has
a
high survival.
Another way to carry out
a
proper secondary prevention programs are early diagnosis (screening) in populations susceptible to
a
particular type of
cancer
. To do this we must have
a
suitable and inexpensive technique able to detect those cases that can be successfully treated in this way is achieved an improvement in forecasting an increase in life expectancy and lower mortality in
a
given group patients. We recommend early diagnosis of
breast
cancer
through mammography for all women over 50 years, the early diagnosis of endometrial
cancer
by cytology with Pap smears in women over age 30, conducting
a
colonoscopy for detection of
cancer
of the colon and rectum in patients with
a
family
predisposition to suffer this type of
cancer
, and so on. There are other methods of screening to detect other cancers
but
has
yet to be clarified its usefulness.
3rd Tertiary Prevention:
Once diagnosed with
cancer
has
to get
a
return as possible to their patient's
normal
life, helping him to overcome his illness both in terms of mental and physical.
Treatment.
The standard treatment for
cancer
is based on three fundamental pillars are: surgery, chemotherapy and radiotherapy. These therapies can be administered jointly or individually depending on the type of tumor and the prognosis.
1) Surgery. Ideally perform
a
curative surgery in which it is removed from total and definitive way the tumor,
but
unfortunately this surgery can be performed only in
tumors
with an early diagnosis, which do not affect vital areas without distant metastases. The cure is achieved only in 60% of the surgery performed with curative intent.
There are other types of surgery are:
Preventive or prophylactic surgery:
the removal of precancerous lesions that can become malignant.
Palliative surgery:
treat by removing part of the tumor mass that causes complications and prevents the patient develops
a
normal
life, improve their quality of life.
Cytoreductive surgery:
it is to reduce the tumor mass, then apply another treatment that can be chemotherapy and / or radiotherapy.
Surgery for metastasis:
sometimes, when metastasis is unique and
has
removed the
primary
tumor, you can try their removal.
2) chemotherapy. It is the use of drugs that selectively act on tumor cells by preventing their proliferation. Most of them operate on the cell cycle, interfering in the synthesis of DNA and RNA or inhibiting the cellular machinery that makes it possible to synthesize new elements to form new tumor cells. This treatment
has
two main
problems
:
The resistance that many of the cells to
develop
drugs, which often requires
a
treatment with several drugs at once.
Adverse effects:
they are not damaged neoplastic cells that are in the process of proliferation, such as bone marrow cells, which regenerate hair cells or
gastrointestinal
tract. So to alleviate these effects requires
a
treatment support.
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