CHEMOTHERAPY

Chemotherapy is defined as the treatment of cancer using chemical substances. When cancer occurs, abnormal cells continue to divide uncontrolled. Anticancer, or chemotherapy drugs, work to destroy cancer cells by preventing them from multiplying. Read more on types of chemotherapy medicines.

Purposes of Chemotherapy

Chemotherapy may be used to achieve different goals, depending on the stage of the cancer at the time of diagnosis and the age and health of the patient. Since chemotherapy for mesothelioma is not considered "curative", the goal is:

• To control the cancer by stopping its spread or slowing its growth.
• To shrink tumors prior to other treatments, such as surgery. This is called neoadjuvant chemotherapy.
• To destroy microscopic disease which may remain after surgery. This is called adjuvant chemotherapy.
• To relieve symptoms, such as pain. This is called palliative chemotherapy, and is given in cases when a drastic reduction in the tumor is not expected.

The most common use for chemotherapy in mesothelioma patients, is as an option for those who are not surgical candidates, however, various cancer centers are now conducting trials using the neoadjuvant approach. Alimta (pemetrexed) is a drug approved by the Food and Drug Administration (FDA) for use with Cisplatin in the treatment of patients with malignant pleural mesothelioma whose disease is either unresectable or who are not candidates for curative surgery. Alimta is the first drug approval specific to mesothelioma.

The Alimta/Cisplatin chemotherapy regimen is the first Food and Drug Administration (FDA) approved treatment specifically for malignant pleural mesothelioma. This is currently considered the most effective first-line treatment for mesothelioma patients who are not surgical candidates. A multi-targeted antifolate drug, Alimta works by blocking the enzymes necessary for DNA copying and cell division. During the clinical trial process, Alimta/Cisplatin improved median survival for pleural mesothelioma patients by approximately three months over treatment with Cisplatin as a single agent. Eli Lilly's information on treatment with Alimta.

As with any medical treatment, it is important to discuss the use of Alimta with your doctor. This conversation should include all pertinent information regarding effectiveness, administration and possible side effects of the drug combination. It is also important to begin vitamin supplementation of B12 by injection during the week prior to treatment (to be repeated every 9 weeks), and folic acid by mouth daily (to be continued until 21 days after the last cycle of Alimta). Additionally, you will be given an oral steroid medication to minimize the risk of skin rash or other possible side effects. Your doctor will have information on the correct dosages of each medication. Be sure to tell your doctor of any other medications you are taking (including non-prescription drugs) so he may be aware of any adverse interactions.

Alimta/Cisplatin is administered to patients on an outpatient basis every 21 days. This cycle of treatment involves a 10-minute IV infusion of Alimta followed by a 2 hour infusion of Cisplatin. How many cycles of treatment you receive will be dependent on your response rate to the drug (regression of the tumor or halt to progression of the disease) and the side effects you might experience.

Side effects of Alimta/Cisplatin are mild to moderate for most mesothelioma patients, i.e., nausea, vomiting and fatigue, and can usually be managed by your doctor. For some patients, however, side effects may be debilitating, and may require a decrease in dosage or removal from the program. All potential side effects should be mentioned to your doctor. Never assume any complaint is minor.

Administration of Chemotherapy

The most common way to administer chemotherapy is intravenously, or through a vein. A thin needle is inserted into a vein in the hand or in the lower arm. Intravenous administration of drugs allows for rapid entry into the blood stream. Drugs may also be delivered via catheters and/or ports.

• Catheters are soft, thin, flexible tubes placed into a large vein in the body. They remain in place for as long as they are needed.
• The catheter may sometimes be attached to a port, a small round plastic or metal disc placed under the skin on the chest. Ports also remain in place for as long as necessary.

Intraperitoneal chemotherapy may also be delivered through a catheter or a port. The catheter is inserted through the abdominal wall. Chemotherapy drugs can then be infused directly into the abdominal cavity. Ports may also be placed under the skin of the abdominal wall and the catheter tunneled between the skin and muscle into the peritoneum.

Side Effects of Chemotherapy

Cancer cells grow and divide more rapidly than normal cells, but some normal cells also multiply quickly, particularly those in the digestive tract, reproduction system, and hair follicles. It is the damage done to normal cells that causes side effects. The type of side effects you might experience and how severe they are, depend on the type of chemotherapy you are receiving, the dosage given and how your own body reacts. Before beginning any chemotherapy treatment, you will be asked to sign a consent form. Before signing the form, be sure your doctor informs you of all the facts regarding the treatment he/she will be administering, including information about the particular drug or combination of drugs to be used, the possible risks or side effects (including nausea and vomiting and peripheral neuropathy), the number of treatments you will receive and how often, and whether it will be given during a hospital stay or on an outpatient basis. More on vomiting and nausea from chemotherapy. More on peripheral neuropathy. More on anti-nausea treatment for chemotherapy patients.

Click here if you are interested in learning more about chemotherapy for mesothelioma and the types of questions you should ask your doctor.

Chemotherapy Schedules

How often you will receive chemotherapy will be determined by your doctor, taking into consideration factors such as the stage of your cancer, the types of drugs you receive, the anticipated toxicities of the drugs and the time necessary for your body to recover from these toxicities. The doctor may also consider whether the goal of the chemotherapy is to control the growth of the cancer, or to ease symptoms associated with the disease.

In general, chemotherapy treatment is administered in "cycles" — a "cycle" being defined as a period of treatment followed by a period of rest. This cycle allows the cancer cells to be attacked by the drugs, and then allows the body's normal cells time to recover. The combination of drugs used, the length of time to administer the drugs, how often they should be repeated and the number of cycles recommended have been analyzed throughly in clinical trials. For mesothelioma patients, the "standard" treatment is a combination of Alimta and cisplatin, administered IV, with a 10 minute infusion of Alimta followed by two hours of cisplatin, given in 21 day cycles. Modifications to this schedule may be made according to what your doctor feels is appropriate in your particular case.

The number of treatment cycles, or the length of time between the beginning and end of chemotherapy may vary, however in general, 3 to 4 cycles of treatment are given before response is evaluated; 2 to 3 cycles are considered a minimum to assess for effectiveness. After response to the treatment has been determined, the following criteria will be used to decide whether chemotherapy should continue:

• If there is shrinkage of the tumor, or the disease is kept stable, chemotherapy may be continued for as long as it can be tolerated and there is no disease progression.
• If there is continued disease progression, chemotherapy will be stopped, and the patient will be given alternative options.

The goal of setting a chemotherapy schedule is to make treatment as effective, timely and trouble-free as possible, but while the drugs are working to kill cancer cells, they may also affect healthy cells causing side effects. One of the most common side effects, and one your doctor will monitor carefully, is a chemotherapy-induced low white blood cell count (neutropenia) which means your immune system is weakened, therefore leaving you more prone to infection. While this side effect is anticipated when someone is undergoing chemotherapy, it can cause delays in your treatment schedule, or changes in the dosage of the drugs you will receive. Click here for more on understanding your blood counts.