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Prostate cancer chemotherapy
is usually used as salvage treatment during hormone
refractory prostate cancer or for advanced prostate
cancer with distant metastasis and has shown success
in extending the life and qualities of life in many
patients.
Chemotherapy’s Role
in Prostate Cancer
Most cases of prostatic adenocarcinoma usually grow
very slowly, meaning the cells divide at a rate that
is similar to that of healthy cells. Chemotherapy, therefore,
is usually not effective for early adenocarcinoma of
the prostate. Why? Chemotherapuetic drugs are both toxic
and systemic. Toxic because they damage cells so badly
that upon division the cell dies. Systemic because chemotherapy
affects all the cells of the body as it circulates through
the blood stream.
Like radiation therapies, chemotherapy
does not destroy the entire body because only cells
that divide soon after being treated will die. Unfortunately,
chemotherapy cannot be focused to any particular area
of the body. All quickly-dividing cells of the body
therefore are affected, including, those in the hair
follicles, skin, gastrointestinal tract, and bone marrow.
The severe and sometimes dangerous side effects of chemotherapy
drugs have often outweighed their benefits as an early
prostate cancer treatment. However, for patients with
advanced disease, chemotherapy can be beneficial in
both extending the life and decreasing pain.
When is Prostate Cancer
Chemotherapy Used?
Prostate cancer chemotherapy is almost always a salvage
therapy for advanced prostate cancer. Usually when treatments
like cryotherapy or prostate surgery fail the next step
is either another type of treatment or prostate cancer
hormone therapy. Once the patient begins hormone therapy,
the disease can be effectively controlled and even halted
for a period of time. Hormone therapy will eventually
fail however and the prostate cancer will continue to
grow and spread. This is called hormone refractory prostate
cancer and is commonly seen during the advanced stages
of prostate cancer. The next step is usually chemotherapy.
Sometimes the disease will metastasize
to the bones and is called advanced prostate cancer
with bone metastasis. Bone metastasis can occur during
hormone therapy treatment but may not be apparent without
a bone scan. Chemotherapy can be used to treat the cells
in the bones that are now dividing malignantly. The
pain associated with bone metastasis can be greatly
relieved by the use of chemotherapy drugs. External
radiation therapy is also sometimes used in conjunction
with chemotherapy as a way to alleviate pain associated
with advanced prostate cancer.
Recently, however, with the creation
and of new and more effective chemotherapy drugs, some
doctors are putting their patients on chemotherapy drugs
before these patients stop responding to hormone therapy.
In some individuals, the earlier use of chemotherapy
has been helpful in slowing the advancement of the disease.
As of now, there are no studies that prove that starting
chemotherapy earlier is better though some patients
have benefited from an early uptake.
What are the Prostate Cancer Chemotherapy Drugs?
Some common chemotherapy drugs used as an advanced prostate
cancer treatment include:
Mitozantrone is an antineoplastic
or anti-tumor antibiotic that is often used with the
steroid prednisone for patients who are in pain due
to bone metastasis.
Doxorubicin is an anti-tumor antibiotic
which damages the nuclei of cells and is derived from
a bacterium Streptomyces Peuceticus.
Vinblastine is an antineoplastic
which disrupts cell division and is derived from the
Madagascar periwinkle.
Paclitaxel is a member of the taxane
group which works by locking the microtubules of cells
and causing the cell to crumble during division.
Docetaxel is another member of the
taxane group which originates in the bark of the Pacific
Yew tree and is difficult synthesize in a laboratory.
Estramustine Phosphate is an alkylating
agent which damages the DNA of cells and lowers the
testosterone produced by the body.
Etoposide works by inhibiting the
process of mitosis in cancerous cells.
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