Purpose: Adjuvant chemotherapy versus observation and chemotherapy at progression was evaluated in 162 patients in a prospective randomized multicenter study. We also evaluated DNA-measurements as an additional prognostic factor.

Patients and methods: Patients received adjuvant carboplatin AUC 7 every 28 days for six courses (n = 81) or no adjuvant treatment (n = 81). Eligibility included surgically staged and treated patients with FIGO stage I disease, grade 1 aneuploid or grade 2 or 3 non-clear cell carcinomas or clear cell carcinomas. Disease-free (DFS) and disease-specific (DSS) survival were end-points.

Results: Median follow-up time was 46 months and progression was observed in 20 patients in the treatment group and 19 in the control group. Estimated five-year DFS and DSS were 70% and 86% in the treatment group and 71% and 85% in the control group. The hazard ratio was 0.98 (95% confidence interval (95% CI): 0.52–1.83) regarding DFS and 0.94 (95% CI: 0.37–2.36) regarding DSS. No significant differences in DFS or DSS could be seen when the log-rank test was stratified for prognostic variables. Therefore, data from both groups were pooled for the analysis of prognostic factors. DNA-ploidy (P = 0.003), extracapsular growth (P = 0.005), tumor rupture (P = 0.04), and WHO histologic grade (P = 0.04) were significant independent prognostic factors for DFS with P < 0.0001 for the model in the multivariate Cox analysis. FIGO substage (P = 0.01), DNA ploidy (P < 0.05), and histologic grade (P = 0.05) were prognostic for DSS with a P-value for the model < 0.0001.

Conclusions: Due to the small number of patients the study was inconclusive as regards the question of adjuvant chemotherapy. The survival curves were superimposable, but with wide confidence intervals. DNA-ploidy adds objective independent prognostic information regarding both DFS and DSS in early ovarian cancer.