MEANING
OF CANCER
Cancer is a group of diseases involving abnormal cell
growth with
the potential to invade or spread to other parts of the body. Not all tumors
are cancerous; benign tumors do not spread to other parts of the body. Possible
signs and symptoms include: a new lump, abnormal bleeding, a
prolonged cough, unexplained weight
loss, and a
change in bowel movements among others. While these symptoms may
indicate cancer, they may also occur due to other issues. There are over 100
different known cancers that affect humans.
Alternatively,
Cancers are a large family of diseases that involve abnormal cell
growth with
the potential to invade or spread to other parts of the body. They form a
subset of neoplasms. A neoplasm or tumor is a group of cells
that have undergone unregulated growth, and will often form a mass or lump, but
may be distributed diffusely.
SIGNS AND SYMPTOMS
When
cancer begins, it invariably produces no symptoms. Signs and symptoms only
appear as the mass continues to grow or ulcerates. The findings that result
depend on the type and location of the cancer. Few symptoms are specific, with many of them also frequently
occurring in individuals who have other conditions. Cancer is the new "great imitator". Thus, it is not
uncommon for people diagnosed with cancer to have been treated for other
diseases, which were assumed to be causing their symptoms.
Local
effects: Local
symptoms may occur due to the mass of the tumor or its ulceration. For example,
mass effects from lung cancer can cause blockage of the bronchus resulting in cough or pneumonia; esophageal cancer can cause narrowing of the esophagus, making
it difficult or painful to swallow; and colorectal cancer may lead to narrowing or blockages in the
bowel, resulting in changes in bowel habits. Masses in breasts or testicles may
be easily felt. Ulceration can cause bleeding that,
if it occurs in the lung, will lead to coughing up blood, in the bowels to anemia or rectal
bleeding,
in the bladder to blood in the urine, and in the uterus to
vaginal bleeding. Although localized pain may occur in advanced cancer, the
initial swelling is usually painless. Some cancers can cause a buildup of fluid
within the chest or abdomen.
Systemic
symptoms: General
symptoms occur due to distant effects of the cancer that are not related to
direct or metastatic spread. These may include: unintentional weight loss, fever, being excessively tired,
and changes to the skin. Hodgkin disease, leukemias, and cancers of the liver or kidney can cause a persistent fever of unknown origin.
Some
cancers may cause specific groups of systemic symptoms, termed paraneoplastic
phenomena.
Examples include the appearance of myasthenia gravis in thymoma and clubbing in lung cancer.
Metastasis:
Cancer
can spread from its original site by local spread, lymphatic spread to regional
lymph nodes or by blood (haematogenous spread) to distant sites, known as
metastasis. When cancer spreads by a haematogenous route, it usually spreads
all over the body. However, cancer 'seeds' grow in certain selected site only
('soil') as hypothesized in the soil and seed hypothesis of cancer
metastasis. The symptoms of metastatic cancers depend on the location of the
tumor, and can include enlarged lymph nodes (which can be felt or sometimes seen under
the skin and are typically hard), enlarged liver or enlarged spleen, which can be felt in the abdomen, pain or fracture of affected bones, and neurological symptoms.
No comments:
Post a Comment