Phase III Trial of Stage I Ovarian Cancer After Surgery

Based on the following adjustment factors, patients will be randomly assigned in a 1:1 ratio to adjuvant chemotherapy or observation groups. 1. Histologic type: clear cell adenocarcinoma/mucinous adenocarcinoma vs. serous adenocarcinoma/other histologic types 2. Facility where a subject is enrolled 3. International Federation of Gynecology and Obstetrics(FIGO) clinical staging: Stage Ia/ Ib vs. Stage Ic(b) Group A: adjuvant chemotherapy group (standard treatment group): While one of the following treatments will be performed, the number of cycles is entrusted to the treatment policy of each facility. Paclitaxel plus Carboplatin (TC) therapy; Paclitaxel (PTX) 175 mg/m2 + Carboplatin(CBDCA) area under curve(AUC) 6 q3weeks day1, 3 to 6 cycles Docetaxel plus Carboplatin (DC) therapy; Docetaxel(DTX) 70 mg/m2 + CBDCA AUC 6 q3weeks day1, 3 to 6 cycles After the start of TC therapy, switching from PTX to DTX due to an adverse event is permitted. Group B: observation group (study treatment group): Observation only, no adjuvant chemotherapy administered.