NEW YORK CITYWeekly irinotecan(Drug information on irinotecan) (Camptosar) and cisplatin(Drug information on cisplatin) (Platinol) can be successfully given as first-line treatment to women with advanced ovarian cancer. The toxicity is manageable, and some patients with suboptimally resected disease achieved an extended disease-free survival, David Spriggs, MD, reported. He is chief of the Developmental Chemotherapy Service at Memorial Sloan-Kettering Cancer Center in New York City.
Ovarian cancer is often responsive to early treatment, and platinum/paclitaxel (Taxol) combinations induce a complete clinical response in 50% to 70% of patients who have advanced disease. Dr. Spriggs said that only about a quarter of patients who have an initial complete response (CR) have a pathological complete remission at a second-look laparotomy. "And only about half of patients who do achieve such a pathologic complete response remain disease-free long-term, so we are always on the lookout for ways to enhance outcome," he said.
Risk stratification has been used in attempts to preserve the results in the good outcome patients while improving or intensifying treatment for poor-prognosis patients. Levels of the tumor marker CA-125 are expected to be a useful indicator in ovarian cancer patients because CA-125 is increased in about 80% of ovarian cancer cases, and normalization of CA-125 levels by the second or third cycle of therapy is a good prognostic factor.
"Since the use of paclitaxel(Drug information on paclitaxel) and platinum began at Memorial Hospital, no patient with a CA-125 greater than 35 U/mL after three cycles of therapy achieved a pathologic CR in our institution," Dr. Spriggs said. Biostatisticians at the Gynecologic Oncology Group (GOG) confirmed that less than 10% of patients with an elevated CA-125 after three cycles went on to achieve pathologic CR in GOG trials.
"Patients with suboptimally debulked ovarian cancer and an elevated CA-125 after three cycles of treatment are a very high risk group for an inadequate response to primary treatment. High-dose chemotherapy unfortunately produced no improvement, so we looked at the possibility of adding different drugs," Dr. Spriggs said."Current treatment of ovarian cancer is graphically shown in the accompanying figure. A primary treatment such as with platinum and paclitaxel will give an early excellent response. When the disease recurs 6 to 12 months later, a second round of platinum/paclitaxel can induce a second response, but eventually all these patients die of the resistant clone, which is shown in red in the figure."