General Cancer Information
Cancer is not one disease, but many diseases that occur
in different areas of the body. Each type of cancer is characterized by
the uncontrolled growth of cells. Under normal conditions, cell reproduction
is carefully controlled by the body. However, these controls can malfunction,
resulting in abnormal cell growth and the development of a lump, mass,
or tumor. Some cancers involving the blood and blood-forming organs do
not form tumors but circulate through other tissues where they grow.
A tumor may be benign (non-cancerous) or malignant (cancerous). Cells
from cancerous tumors can spread throughout the body. This process, called
metastasis, occurs when cancer cells break away from the original tumor
and travel in the circulatory or lymphatic systems until they are lodged
in a small capillary network in another area of the body. Common locations
of metastasis are the bones, lungs, liver, and central nervous system.
The type of cancer refers to the organ or area of
the body where the cancer first occurred. Cancer that
has metastasized to other areas of the body is named
for the part of the body where it originated. For example,
if breast cancer has spread to the bones, it is called "metastatic
breast cancer" not bone cancer.
Source: 411Cancer.com |
What You Should Know
Cancer treatment may vary depending upon the type of cancer, the stage of cancer
and the goal of treatment. Often, one or more treatment modalities may be used
in order to provide the most complete treatment for the patient. Increasingly,
it is common to use several treatment modalities concurrently or in sequence,
with the goal of preventing both local and systemic recurrence. This is referred
to as multi-modality treatment of the cancer. These modalities may include surgery,
radiation therapy, chemotherapy and/or biological therapy.
Discussing the Effectiveness of Treatment
It is important that patients are able to evaluate treatment options and to understand
how cancer treatments are evaluated and described so that they can work with
their physician to make informed treatment choices,. Understanding the goals
of a specific therapy, as well as the risk and benefits it poses, will help patients
decide which treatment is most appropriate for their situation. Patients typically
receive cancer treatment in order to cure the cancer, prolong the duration of
their life or alleviate symptoms caused by the cancer and improve their quality
of life. These potential benefits of treatment must be balanced against the risks
of treatment. Some risks posed by various cancer treatments may include time
away from family and friends, uncomfortable side effects of therapy and/or long-term
complications or death.
The most common term used to describe the effectiveness of cancer treatment is
remission. Remission means that the cancer has disappeared and can no longer
be measured using existing technology. Oncologists use the terms partial and
complete remission to describe partial or complete disappearance of cancer after
treatment. A cancer cannot be cured if a remission is not obtained; however,
a remission does not always ensure that a cancer is cured. The best ways to evaluate
the benefits of treatment are to examine the duration of remission, survival
and disease-free survival (cure). Since it often takes many years to determine
whether a new treatment is better than a previous treatment, remission rates
may be useful for comparing therapies when patients have not been evaluated long
enough to know whether their chance of cure or survival is improved.
Throughout this site, we report each treatment's survival benefit, which is the
improvement in the duration of survival, or the proportion of patients surviving
for a defined period of time after receiving treatment. If a cancer returns after
a remission, it may be referred to as progression of the cancer, recurrence,
or relapse. When patients have no evidence of cancer 5 years after initial treatment,
we refer to the 5-year disease or progression-free survival rate, which is consistent
with cure for most but not all cancers.
Treatment of cancer is associated with risks. It is important that patients evaluate
the risks and benefits of treatment within the context of the overall goal of
receiving cancer therapy.
Cancer treatment may be inconvenient, prolonged, or unavailable close to home.
These are important considerations when evaluating treatment options, but not
typically mentioned in medical journals reporting the results and benefits of
new treatments. All cancer treatments are associated with side effects. Side
effects are unwanted complications of cancer treatment. Side effects occur because
many of the body's normal cells, in addition to the cancer cells, are affected
by the cancer treatment. Side effects may be acute short-term complications of
therapy, chronic longer-term complications of therapy, or permanent. When cancer
treatments are evaluated, side effects are measured and reported as part of the
treatment evaluation. Examples of acute side effects include nausea and vomiting
associated with chemotherapy or mouth sores (mucositis) resulting from the effects
of radiation or chemotherapy that has affected normal as well as cancerous tissue.
Some treatments are associated with a risk of dying from complications of therapy,
and this is referred to as the treatment-related mortality.
Finally, although this web site provides information from the most current medical
literature available on the treatment of cancer, patients may still find that
there are differences in the potential benefits of treatment across diseases
and within diseases across stages. The differences in treatment outcomes are
the major factors behind the continuation of research within the oncology community.
However, everyone should understand that there are more cancer treatments available
and more undergoing assessment in clinical trials than ever before.
Principles of Cancer Treatment
Depending on the stage of cancer, one or more treatment modalities may be required
to achieve the best results. Cancer treatments aim to prevent the cancer from
spreading locally or recurring/relapsing at sites distant from the original location
(metastasis). Cancer therapy may consist of one or more treatment modalities
delivered concurrently or in sequence, including surgery, radiation, chemotherapy,
and/or biologic therapy.
Surgery:
Surgery is a local treatment used to remove visible tumors. In addition, surgeons
frequently remove the tissue adjacent to the cancer during surgical resection
of a tumor. Information gained about the tumor during surgery is useful in predicting
the likelihood of tumor recurrence and the need for other treatment modalities.
Radiation Therapy:
Radiation therapy, or radiotherapy, uses high-energy rays to damage or kill cancer
cells by preventing them from growing and dividing. Similar to surgery, radiation
therapy is a local treatment used to eliminate or eradicate visible tumors. Radiation
therapy is not typically useful in eradicating cancer cells that have already
spread to other parts of the body. Radiation therapy may be externally or internally
delivered. External radiation delivers high-energy rays directly to the tumor
site from a machine outside the body. Internal radiation, or brachytherapy, involves
the implantation of a small amount of radioactive material in or near the cancer.
Chemotherapy:
Chemotherapy is the general term for any treatment involving the use of drugs
to kill cancer cells. Cancer chemotherapy may consist of single drugs or combinations
of drugs. Chemotherapy can be administered through a vein, injected into a body
cavity or delivered orally in the form of a pill. Chemotherapy is different from
surgical or radiation therapy in that the cancer-fighting drugs circulate in
the blood to parts of the body where the cancer may have spread and can kill
or eliminate cancers cells at sites great distances from the original tumor.
As a result, chemotherapy is considered a systemic treatment.
Biological Therapy:
Biological therapy is referred to by many terms including immunologic therapy,
immunotherapy, or biotherapy. Biological therapy is a type of treatment that
uses the body's immune system to facilitate the killing of cancer cells. Types
of biological therapy include interferon, interleukin, monoclonal antibodies,
colony stimulating factors or cytokines and vaccines.
Hormone Therapy:
Hormones are naturally occurring substances in the body that stimulate the growth
of hormone sensitive tissues, such as the breast or prostate gland. When cancer
arises in breast or prostate tissue, its growth and spread may be caused by the
body's own hormones. Therefore, drugs that block hormone production or change
the way hormones work, and/or removal of organs that secrete hormones, such as
the ovaries or testicles, are ways of fighting cancer. Hormone therapy, similar
to chemotherapy, is a systemic treatment in that it may affect cancer cells throughout
the body.
Source: 411Cancer.com |
