Adjuvant treatment for early epithelial ovarian cancer: results of two randomised clinical trials comparing cisplatin to no further treatment or chromic phosphate (32P). G.I.C.O.G.: Gruppo Interregionale Collaborativo in Ginecologia Oncologica.

BACKGROUND

From 1983 to 1990, 271 consecutive patients with stage I ovarian cancer entered two randomised trials, aimed at assessing the role of adjuvant chemotherapy after radical surgery in early stages of ovarian cancer. Trial I compared cisplatin (50 mg/m2 with repeated courses every 28 days for 6 cycles) to no further therapy in F.I.G.O. stage Ia & b Grade II-III patients; trial II compared cisplatin (same dose and schedule) to 32P in Iaii & bii and Ic patients.

METHODS

Both studies were multicentric and centrally randomized. Treatment was allocated by phone and stratified by center. All patients satisfying major eligibility criteria (histological and grade, no previous neoplasms) were analysed according to treatment allocated by randomisation.

RESULTS

With a median observation time of 76 months, cisplatin significantly reduced the relapse rate by 65% (HR = 0.35; 95% CI = 0.14-0.89, p = 0.028; Cox Model) in trial I and 61% (HR = 0.39; 95% CI = 0.19-0.77, p = 0.007; Cox Model) in trial II. Survival was not significantly different (trial I - Kaplan-Meier overall 5-year survival: cisplatin = 88%, control = 82%, HR = 1.15; 95% CI = 0.44-2.98; p = 0.773; Cox Model); trial II - overall 5-year survival: cisplatin = 81%, 32P = 79%, HR = 0.72; 95% CI = 0.37-1.43; p = 0.354; Cox model). In both studies the risk of dying after relapse increased for patients originally randomized to the cisplatin arms: in trial I, 6 of 7 patients in the cisplatin relapsed arm and died of tumor compared with 8 of 14 patients in the control arm. In trial II 11 of 12 patients on cisplatin, and 18 of 26 on 32P succumbed to tumor recurrence.

CONCLUSION

Adjuvant cisplatin treatment in early ovarian cancer significantly prevents relapse in comparison to 32P in stage IC patients or to no immediate treatment in earlier stage women. The impact of cisplatin adjuvant treatment on survival remains, however, unclear.