The review included 13 RCTs (n approximately 2,902), eight of which reported findings solely for women with stage I ovarian cancer. The exact number of participants with stage I cancer was unclear as some trials included other cancer stages.
Adjuvant chemotherapy was associated with statistically significantly improved 5-year survival compared with no adjuvant treatment (RR 0.74, 95% CI: 0.58, 0.94, p=0.01) and reduced risk of recurrence (RR 0.70, 95% CI: 0.58, 0.86, p=0.0004). There was little heterogeneity (I-squared of 0% for each outcome). These findings were based on five RCTs where most of the participants did not undergo lymphadenectomy as part of surgical staging. When the four RCTs with optimal or modified surgery were pooled, there was no statistically significant difference in 5-year survival (RR 0.81, 95% CI: 0.58, 1.21) or disease recurrence (RR 0.73, 95% CI: 0.52, 1.02).
Two RCTs compared adjuvant radiotherapy versus no adjuvant radiotherapy, but both had methodological limitations such as small sample sizes and one had excluded over 50% of the patients from the analysis. Conclusions could not be drawn.
Three RCTs compared chemotherapy versus radiotherapy, but the findings were not pooled as two studies were more than 20 years old and used outdated treatment regimens. None of the studies reported statistically significant differences in survival between groups, although one did report a statistically significant difference in disease recurrence (6% for chemotherapy versus 30% for radiotherapy, p<0.05).
Four RCTs compared adjuvant chemotherapy with radioactive chromic phosphate. None of the studies reported statistically significant differences in survival between groups and the trials were not pooled.
Two RCTs compared two different forms of chemotherapy, but both were reported as abstracts so only limited information was available. Neither reported statistically significant differences in survival or recurrence.
The authors provided a narrative summary of the toxicity associated with each regimen, but noted that the measurement scales used varied between studies and were not reported.