Chemotherapy involves using drugs to destroy cancer cells. Many of these drugs destroy cancer cells by preventing them from growing and dividing rapidly. Unfortunately, many normal cells in the body also divide rapidly and are damaged by chemotherapy.
Researchers have developed medications that may help to minimize some of these side effects. For example, epoetin alfa (e.g., Procrit, Epogen), which is a synthetic hormone that stimulates red blood cell production, is available to treat chemotherapy-related anemia. Also, the cell-protecting compound amifostine (Ethyol; Alza Pharmaceuticals, Palo Alto, CA/US Bioscience, West Conshohocken, PA) is being tested for its ability to protect normal tissue against the toxic effects of chemotherapy and radiotherapy.
There are four ways to administer chemotherapy. The most common method is intravenous (through a vein) injection. Other methods include intraperitoneal (into the abdominal cavity) injection, oral administration (by mouth), and intramuscular (into a muscle) injection.
Many chemotherapy drugs are given by intravenous injection over a 3-week treatment period, allowing normal cells to recover from the effects of the drugs. Also, because different chemotherapy drugs affect different phases of the cancer cell cycle, combinations of the drugs may be used. Combination chemotherapy helps to increase the cancer-fighting potential of treatment and also helps to keep cancer cells from becoming resistant to individual drugs.
The frequency, dosing, and choice of chemotherapies are determined by a number of factors (e.g., the type of ovarian cancer, the woman's response to and recovery from chemotherapy, the overall health of the patient). For example, patients with kidney disease are not given chemotherapy drugs that can cause kidney toxicity. In addition, regular blood tests are performed to monitor the recovery rates of blood cells (e.g., red blood cells, white blood cells, platelets).
The intraperitoneal method for delivery has been shown to increase survival in patients with Stage III ovarian cancer who have undergone surgery. In this treatment, high doses of chemotherapy drugs are infused directly into the abdominal cavity through a catheter to destroy remaining cancer cells. These drugs eventually enter the bloodstream and may destroy any cancer cells that have spread.
Intraperitoneal chemotherapy usually is administered in 6 cycles, approximately every 3 weeks. Side effects of treatment, which can be severe and include abdominal pain, bloating, fatigue, and infection, may prevent patients from completing all 6 cycles.
Intravenous injection of chemotherapy may be performed on an outpatient basis or, if it takes place over several days, the patient may be admitted to the hospital. In some cases, a catheter (flexible tube) may be placed in a vein in the chest or neck for administration of the drugs. The catheter may be implanted within the skin (e.g., Mediport catheter) or remain external (e.g., Groshong catheter).
Oral drugs such as etoposide (VP-16; VePesid), melphalan (Alkeran), and hexamethylamine (Hexalen, altretamine) may be given in pill form for first- or second-line ovarian cancer treatment.
In the United States, the initial treatment of ovarian cancer is now in transition, with most patients receiving primary therapy with drugs that contain platinum and taxane compounds (e.g., cisplatin, carboplatin, paclitaxel); however, other drugs, such as "mustards" (e.g., melphalan) and anthracyclines (e.g., doxorubicin) also show first-line activity in ovarian cancer.
The dose, timing, and choice of chemotherapies are determined by factors such as the patient's type and stage of ovarian cancer, her body's response to and recovery from chemotherapy, and her health status.
The following drugs are the most common "first-line" treatment options for ovarian cancer.
All of these drugs have been approved by the FDA (Food and Drug Administration) for the treatment of ovarian cancer.
In general, most ovarian cancer patients undergo six courses of chemotherapy if they have a good response to treatment. At the completion of each two (2) courses of chemotherapy, the degree of response is evaluated. The patient is physically examined, a CT (computed tomography) scan may be taken, and her blood is analyzed for levels of the tumor marker CA125.
Remission—no evidence of disease—is most likely among patients whose CA125 levels drop below the normal value of 35 U/mL before their third chemotherapy treatment.
Hexamethylamine (Hexalen, altretamine) and topotecan hydrochloride (Hycamtin) have been approved by the FDA for use as second-line, or "salvage," agents in ovarian cancer (for example, in metastatic ovarian cancer patients in whom initial or subsequent chemotherapy with paclitaxel and cisplatin has failed).
Paclitaxel (Taxol), a taxane compound, is the treatment of choice in platinum-resistant ovarian cancer patients who have not received prior taxane therapy. If the individual's tumor continues to grow after paclitaxel therapy, several other drugs may be considered, such as 5-fluorouracil (5-FU) plus leucovorin (a drug used to counteract folic acid antagonists), doxorubicin HCl liposome injection (Doxil) ifosfamide (Ifex), oral etoposide (VP-16; VePesid), and investigational drugs.