Medications
Following surgery, patients other than those with early-stage, low-grade disease usually undergo chemotherapy. Unlike surgery and radiation, which treat the malignant tumor and the area surrounding it, drug therapy destroys rapidly dividing cells throughout the body and so is known as systemic therapy. Ovarian cancers are very sensitive to chemotherapy and often respond well initially. Unfortunately, in most cases, ovarian cancer recurs. With treatment advances, however, more than half of women now survive five years or longer. Physicians are now approaching this disease as a chronic and potentially long-term illness that requires identifying the disease recurrence as soon as possible, administering treatments that are as effective as possible without causing suffering, and partnering with the patient in determining her own best course.
Drugs Used in Chemotherapy
Standard Chemotherapy. The standard initial chemotherapy uses a combination of the following:
- A platinum-based agent, such as carboplatin (Paraplatin) or cisplatin (Platinol). At this time carboplatin is preferred over cisplatin in the combination because carboplatin is as effective as cisplatin but is less toxic and can be administered in a more convenient, outpatient regimen.
- A taxane, such as paclitaxel (Taxol) and docetaxel (Taxotere). Currently paclitaxel is the drug most often used as initial therapy in combination with a platinum agent. Docetaxel, however, is less toxic to the nervous system (but has more adverse effects on blood cell production). Taxotere is now commonly substituted for Taxol.
Approximately 70% of women will experience a response to paclitaxel and carboplatin chemotherapy (i.e., a reduction in tumor size). Older women (over 60) may benefit as much as younger ones from this regimen. Of note, a comparison study in 2002 reported that the use of a platinum-based agent alone was as effective as paclitaxel/platinum agent combination and had lower toxicity. More research is needed to confirm these findings or to discover if specific patients will benefit from the combination compared to the single agent. Other drugs that may prove to be useful first line agent are pegylated liposomal doxorubicin, topotecan, and gemcitabine (which are discussed below.)
Chemotherapy Agents Studied for Relapsed or Refractory Cancer. Unfortunately, some ovarian tumors are resistant to platinum drug. Even in patients who respond, the disease eventually becomes resistant to the first-line drugs and the cancer returns. Various approaches for increasing responsiveness to these agents are being investigated. Investigators are studying two approaches for preventing relapse after remission:
- Developing more effective drug combination regimens to increase initial response rates and duration of the response.
- Develop maintenance drugs to prevent or delay relapse.