Ifosfamide Plus Paclitaxel Extends Life for Patients With Uterine Carcinosarcoma
Women with a rare, aggressive form of uterine cancer who were treated with the drugs ifosfamide and paclitaxel lived a median of five months longer than women who were treated with ifosfamide alone.
Journal of Clinical Oncology, February 10, 2007 (see the journal abstract).
(J Clin Oncol. 2007 Feb 10;25(5):526-31)
Uterine carcinosarcoma is a rare, fast-growing form of cancer of the uterus. An unusual feature of these tumors is that they contain a mix of two types of cancer cells.
Surgery to remove the uterus (and sometimes the ovaries as well) can cure these mixed uterine tumors if the disease has not spread beyond the uterus. When the disease has spread, however, it usually does not respond well to chemotherapy and the outlook for patients is poor.
In a preliminary study, the drug ifosfamide showed promising results in patients with mixed tumors that had either come back or spread beyond the uterus. Adding the drug cisplatin to ifosfamide, however, resulted in higher rates of adverse effects and no improvement in survival. The current study was conducted to find out whether adding the drug paclitaxel to ifosfamide would result in better survival than treatment with ifosfamide alone.
This phase III study involved 179 women with mixed tumors that had come back or spread beyond the uterus. Most of the patients had had surgery and some had also received radiation therapy, but none had had previous chemotherapy. Between 1997 and 2004, they were randomly assigned to receive either ifosfamide alone or ifosfamide plus paclitaxel.
The study was conducted by researchers with the Gynecologic Oncology Group (GOG), a National Cancer Institute-supported clinical trials cooperative group. Participants were enrolled at a number of sites in the United States. The principal investigator was Howard D. Homesley, M.D., of the Brody School of Medicine in Greenville, North Carolina.
At the time of this report, 150 patients had died and the median follow-up period for living patients was 20 months. Women treated with ifosfamide plus paclitaxel survived for a median of 13.5 months, compared with 8.4 months for those treated with ifosfamide alone. This difference was statistically significant. After taking patients’ performance status into account, the risk of death for patients who received ifosfamide plus paclitaxel was 31 percent lower than for those who received ifosfamide alone.
Tumors either disappeared or shrank by at least half in 45 percent of patients treated with the combination regimen, compared with 29 percent of those treated with ifosfamide alone. Progression of disease was delayed for a median of 5.8 months in the combination-therapy group, compared with 3.6 months in the ifosfamide-only group.
Patients taking paclitaxel plus ifosfamide were more likely than those taking ifosfamide alone to experience a low platelet count as well as hair loss, pain, tingling, numbness, swelling, or weakness.
Ted Trimble, M.D., M.P.H., a gynecologic cancer specialist with the National Cancer Institute’s Cancer Therapy Evaluation Program, agrees with the study authors that this is the first randomized study to show better survival for patients with advanced mixed uterine tumors who were treated with a combined regimen of two chemotherapy drugs, compared with patients treated with a single drug.
Although the regimen of ifosfamide plus paclitaxel extended patients’ lives, it did not cure their disease, says Trimble. The study authors agree that better drugs are needed to treat this disease.
GOG researchers are currently conducting a phase III study (called GOG 0209) to compare two multidrug chemotherapy regimens in patients with endometrial cancer, the most common form of cancer of the uterus. The results of this study should also benefit patients with mixed uterine tumors, says Trimble.