A new study finds chemotherapy improves survival and reduces the risk of recurrence in women with stage I ovarian cancer (cancer that has not spread beyond the ovary). But it remains unclear which patients would most benefit from adjuvant chemotherapy and what the optimal treatment regimen would entail.
The findings come from an analytical review of data from 13 randomized control trials (RCTs), which will be published in the November 1, 2004 issue of CANCER, a peer-reviewed journal of the American Cancer Society.
About one quarter of all ovarian cancers are caught while confined to the ovaries, when five-year survival is 85 percent. But the therapeutic benefit of adjuvant chemotherapy remains controversial. All physicians agree that surgery that includes staging is critical to survival. Some doctors may prefer not to offer chemotherapy for their patients, since eight in ten are adequately treated by surgery alone. They could argue that giving all stage I patients chemotherapy would lead to unnecessary adverse events with no survival benefit for the majority of patients.
Given the controversy, Laurie Elit, M.D., of the Juravinski Regional Cancer Centre in Ontario, Canada and her colleagues conducted a meta-analysis of RCT data published since 1965.
First, adequate surgical staging was a prognostic factor for cancer survival. Most studies in this review did not show adequate staging of patients. Second, patients who received any adjuvant chemotherapy had a lower risk of death (relative risk, 0.74) and recurrence (relative risk, 0.70) than those who did not receive chemotherapy. However, insufficient data and conflicting data exist regarding the optimal regimens (e.g., three versus six cycles), optimal doses, and the role of adjuvant radiotherapy.
The authors strongly recommend that women receive appropriate surgical staging: "women with optimally staged stage I ovarian cancer, a pathology review by a gynecologic pathologist, and good prognostic factors (stage Ia or stage Ib grade 1) have an excellent prognosis without adjuvant chemotherapy." They add: "There is evidence adjuvant chemotherapy improves survival and decreases recurrence rates. What remains to be defined is the population of stage I patients who would most benefit from adjuvant therapy, the optimal chemotherapy regimen, and the dose and duration of treatment."