Chemotherapy (chemo) is the use of drugs to destroy or control cancer cells. These drugs can be taken by mouth or given in a vein or a muscle. They enter the bloodstream and reach all areas of the body, making this treatment useful for cancers such as multiple myeloma that often spread widely.
Many different types of drugs are used to treat multiple myeloma.
Traditional chemo
Chemotherapy drugs that may be used to treat multiple myeloma include melphalan, vincristine, cyclophosphamide, carmustine, and doxorubicin (and liposomal doxorubicin). Combinations of these drugs are more effective than any single drug. Sometimes these drugs are combined with other types of drugs like corticosteroids or immunomodulating agents.
Corticosteroids
Corticosteroids are an important part of the treatment of multiple myeloma and can be used alone or combined with other drugs. Corticosteroids also help decrease the nausea and vomiting that other chemotherapy may cause. These drugs have side effects for patients including high blood sugar, increased appetite, and problems sleeping. When used for a long time, corticosteroids also suppress the immune system. This leads to an increased risk of serious infections. Most of these side effects go away with time after the drug is stopped. The drugs most often used in treating myeloma are dexamethasone and prednisone.
Immunomodulating agents
Thalidomide: The drug thalidomide was first used as a sedative. When it was found to cause birth defects, it was taken off the market. Later, it became available again as a treatment for multiple myeloma. Side effects of thalidomide include drowsiness, fatigue, severe constipation, and neuropathy (painful nerve damage). The neuropathy can be severe, and may not go away after the drug is stopped. There is also an increased risk of serious blood clots (that start in the leg and can travel to the lungs). Because thalidomide causes severe birth defects if taken during pregnancy, this drug can only be obtained through a special program run by the drug company that makes it.
Lenalidomide (Revlimid®) is a newer drug that is similar to thalidomide. It works well in multiple myeloma. The most common side effects of lenalidomide are thrombocytopenia (low platelets) and low white blood cell counts. It can also cause painful nerve damage. The risk of blood clots is not as high as that seen with thalidomide, but it is still increased. Like thalidomide, access to lenalidomide is also tightly controlled out of concern about possible serious birth defects.
Other drugs
Bortezomib (Velcade®) is a newer type of drug known as a proteasome inhibitor. It works by stopping enzyme complexes (proteasomes) in cells from breaking down proteins important for keeping cell division under control. It appears to affect tumor cells more than normal cells, but it is not without side effects.
Common side effects of this drug include nausea and vomiting, tiredness, diarrhea, constipation, decreased platelet blood count (causing easier bruising and bleeding), fever, and decreased appetite. Bortezomib can also cause peripheral neuropathy (numbness or tingling in the arms and legs).
Drug treatment
These drugs can be used alone or in combination. Often different classes of drugs are combined for treatment. For example:
- Melphalan and prednisone (MP), with or without thalidomide or bortezomib
- Vincristine, doxorubicin (Adriamycin®), and dexamethasone (called VAD)
- Thalidomide (or lenalidomide) and dexamethasone
- Bortezomib and dexamethasone, with or without doxorubicin or thalidomide
- Liposomal doxorubicin, vincristine, dexamethasone
The choice and dose of drug therapy depend on many factors, including the stage of the cancer and the age and kidney function of the patient. If a stem cell transplant is planned, most doctors avoid using a drug like melphalan that can damage the bone marrow.
Side effects
Chemotherapy drugs kill cancer cells but can also damage normal cells. Careful attention is given to avoid or reduce the side effects of chemotherapy. These side effects depend on the type and dose of drugs given and the length of time they are taken. Common side effects of chemotherapy include:
- Hair loss
- Mouth sores
- Loss of appetite
- Nausea, and vomiting
- Low blood counts
Chemotherapy often leads to low blood counts, which can cause the following:
- Lowered resistance to infection (low white blood cell counts)
- Easy bruising or bleeding (low blood platelets)
- Fatigue (low red blood cells).
Most side effects are temporary and go away after treatment is finished.
If you have side effects, your cancer care team can suggest steps to ease them. For example, drugs can be given along with the chemotherapy to prevent or reduce nausea and vomiting.
In addition to these temporary side effects, some chemotherapy drugs can permanently damage certain organs such as the heart or kidneys. These possible risks are carefully balanced against their benefits, and the health of these organs is carefully monitored during treatment. If serious organ damage occurs, the drug that caused it is stopped and replaced with another.
Feedback
