HOUSTON, TexasDavid M. Gershenson, MD, painted a bleak picture of
current treatment for advanced ovarian cancer and suggested that new agents
such as topoisomerase inhibitors should be studied further in clinical trials.
Dr. Gershenson said that although CA-125 and transvaginal ultrasound are used
for screening, they have limited efficacy, with the result that over 70% of
ovarian cancers have already spread beyond the ovary by the time they are
"These advanced stages have an 80% to 90% response rate to current
therapy, but they nearly all relapse, and 5-year survival is only about
15%," he said. He is professor and chairman of the Department of
Gynecologic Oncology at the University of Texas M. D. Anderson Cancer Center in
Dr. Gershenson updated the data from a phase II, single-agent irinotecan (Camptosar)
trial he presented earlier this year at the American Society for Clinical
Oncology (ASCO) annual meeting. This protocol evaluated the efficacy of
irinotecan in patients who had recurrent epithelial ovarian cancer.
"We found that irinotecan has moderate activity and acceptable toxicity
in patients with epithelial ovarian cancer. Response rates were well within the
range reported for the commonly accepted drugs used for refractory ovarian
cancer," Dr. Gershenson reported.
Followed Japanese Studies
"There is a suggestion from Japanese studies that a weekly schedule
might be more effective than biweekly or every three weeks schedules, but none
of these ideas have been tested in randomized trials in ovarian cancer.
Clearly, we need to pursue the use of irinotecan, and we need confirmatory and
well-controlled trials," Dr. Gershenson said.
The M. D. Anderson trial followed a number of small Japanese phase II
studies. The first was a phase II trial of 15 patients with recurrent ovarian
cancer that reported a 20% response rate including one complete response (CR).
The major toxicities were leukopenia, anemia, and nausea and vomiting. A
subsequent study from the same research group included 55 ovarian cancer
patients treated either with irinotecan 100 mg/m² weekly or 150 mg/m² every 2
weeks. Partial responses occurred in 13 of 55 patients (23.6%). "There was
a suggestion that the response rate was better for the weekly schedule, 24% vs
14% for the biweekly schedule," Dr. Gershenson said. The major toxicities
were leukopenia (57%), anemia (25%), and diarrhea (19%).