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SkinCancerNet Article
Chemotherapy: What Every Patient Should Know
Chemotherapy is the use of
cancer-fighting medications to stop the growth of malignant cells.
It works by either killing the cells or preventing them from
dividing. When treating skin cancer, chemotherapy may be topical
(applied to the skin) or systemic (taken by mouth or injected).
Topical Chemotherapy
Topical chemotherapy is used to treat non-melanoma skin cancer
that is limited to the top layer of skin. It also is used to treat
actinic keratoses (AKs), lesions that can develop on skin that has
received years of sun exposure. AKs have the potential to progress
to squamous cell carcinoma, a type of skin cancer. Actinic keratoses
are also called “solar keratoses.”
A topical chemotherapy medication that dermatologists prescribe is
fluorouracil, commonly called 5-FU. 5-FU is applied by the
patient as directed, usually twice a day for several weeks. The
medication works to erode cancerous and pre-cancerous lesions, and
intense skin irritation can occur. Due to skin irritation, the
patient may be instructed to use cycle therapy — a form of treatment
in which the medication is applied for a specified duration, stopped
for a pre-determined amount of time, and then resumed.
Systemic Chemotherapy
Systemic chemotherapy may be part of the treatment plan when skin
cancer has metastasized (spread) or the risk of metastasis is high.
When treating skin cancer, chemotherapy may be administered:
When administered after surgery, the
chemotherapy is called “adjuvant chemotherapy.” The purpose of an
adjuvant therapy is to increase the effectiveness of the primary
therapy. When chemotherapy is used after surgical removal of the
tumor, the purpose is to kill undetected cancerous cells.
When treating metastatic skin cancer, the goal of chemotherapy is
either 1) remission or 2) to ease symptoms for a patient with
advanced, and probably incurable, cancer.
The form of chemotherapy given depends on the stage, site(s) of the
tumor(s), and patient’s ability to tolerate side effects. Systemic
chemotherapy may involve the use of a single anti-cancer medication
or the combination of two or more medications. When the area to be
treated is a limb, isolated limb perfusion or isolated limb infusion
may be used.
Isolated limb perfusion (ILP) is a type of chemotherapy used
to treat:
ILP involves an operation on the blood
vessels and is used to treat metastatic tumors when the area to be
treated can be surgically isolated from the rest of the body. To
perform an ILP, the surgeon creates a temporary arterial-venous loop
that disconnects the limb’s blood circulation from the rest of the
body. A tube is inserted into the arterial-venous loop in order to
inject a high-dose of the chemotherapeutic medicine(s). This high
dose, which would cause severe side effects without limb isolation,
can be given because the anti-cancer medications cannot reach the
general circulation. The high dose is given to increase the “kill
rate.”
During ILP, a radioisotopic tracer is usually used to monitor the
precise flow of the anti-cancer medication(s) to the tumor site(s).
A heating unit is typically used to warm the medication(s) before it
is placed into the arterial-venous loop, and a warming blanket keeps
the tissue receiving the chemotherapeutic medication at a constant
temperature. Some studies have shown that warming the anti-cancer
medication increases its anti-tumor activity.
The chemotherapeutic medication most often used during ILP is
melphalan, which works by binding together the DNA in cancer cells
and leads to the cell death. Melphalan may be used alone or combined
with another anti-cancer agent, such as nitrogen mustard, cisplatin,
or dacarbazine.
Studies have shown that in a substantial number of patients, ILP can
achieve complete remission of tumors in the treated leg and may
eliminate the need for limb amputation. However, metastatic disease
recurs in a substantial number of patients after ILP, and ILP has
not been shown to increase overall survival of patients with
metastatic melanoma.
A newer form of limb isolation is undergoing evaluation in U.S.
clinical trials. It is called isolated limb infusion (ILI).
It is used to treat advanced melanoma confined to an arm or leg.
During ILI, high doses of chemotherapy medications are injected into
an artery or vein within the affected limb while the blood is
temporarily stopped with a tourniquet. It is believed that infusion
may kill more tumor cells and cause less damage to healthy tissue.
How Chemotherapy is Administered
Chemotherapy is usually administered on an outpatient basis and
is typically given in cycles. This means that treatment is given for
a specified time and a rest period follows. Another cycle of
treatment followed by rest is given as needed.
Chemotherapy may be combined with another form of treatment called
immunotherapy, which uses the patient’s own immune system to fight
the cancer. When chemotherapy is combined with immunotherapy, side
effects tend to be less severe. Radiation therapy may be combined
with chemotherapy to ease the symptoms of advanced metastatic
melanoma.
Side Effects
Chemotherapy damages normal cells as well as cancer cells, and
side effects, such as nausea, vomiting, mouth sores, fatigue, and
hair loss are well known. What surprises many patients and family
members is that side effects, such as nausea and hair loss do not
always occur. Side effects depend on the medication used. Be sure to
discuss side effects with your physician so you know what you can
expect. It is important to know that there are many ways to minimize
side effects. In fact, the coping techniques are so numerous that
they are beyond the scope of this article. If chemotherapy becomes a
treatment option, be sure to discuss ways to manage side effects
with your physician.
Systemic Chemotherapy Medications Used to Treat Melanoma
Dacarbazine (DTIC) is the only anti-cancer medication that has
been approved by the U.S. Food and Drug Administration (FDA) for
treating metastatic melanoma. Studies indicate that it has been
effective in reducing tumors in approximately 15% of patients, and
remission is typically maintained for 3 to 6 months. Dacarbazine is
given intravenously (by IV) for 1 to 10 days. The dosing schedule
depends on the patient’s condition and ability to tolerate side
effects that may include nausea, vomiting, pain at the injection
site, and fatigue.
Temozolamide, another anti-cancer medication, belongs to the
same class of medications as DTIC. Both are alkylating agents, which
means the medications work by binding together the DNA in cancer
cells. This action prevents the cells from growing, and the cells
die. Temozolamide is given in pill form rather than intravenously.
Tumor reduction is similar to DTIC.
Other anti-cancer medications that have been tested as a single
agent (one anti-cancer medication is selected for its activity in
treating the patient’s type and stage of metastatic disease) to
treat metastatic melanoma include vincristine, vinblastine,
cisplatin, and carboplatin. None, to date, has shown a better
response rate than DTIC.
While DTIC and temozolamide have been effective in reducing tumors
in approximately 15% of patients and maintaining remission for 3 to
6 months, no single medication when used alone has been shown to
produce long-term (5-year) survival in a significant number of
patients with metastatic melanoma.
Anti-cancer medications are sometimes given via combined-agent
chemotherapy, the combining of two or more chemotherapeutic
agents. Combined-agent chemotherapy is used to either 1) enhance the
effectiveness of chemotherapy or 2) avoid the cancer cells from
growing resistant to a single agent. DTIC is usually one of the
anti-cancer medications used in the combination.
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content solely developed by the American Academy of Dermatology |
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