1. ¹Department of Obstetrics and Gynaecology, National Defence Medical College, Tokorozawa, Saitama 359-8513, Japan
2. ²Department of Obstetrics and Gynaecology, Tohoku University, Sendai, Miyagi 980-8574, Japan
3. ³Department of Gynaecology, Aichi Cancer Center Hospital, Nagoya, Aichi 464-8681, Japan
4. ⁴Department of Obstetrics and Gynaecology, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
5. ⁵Department of Obstetrics and Gynaecology, Osaka City General Hospital, Toshima-ku, Osaka, Osaka 534-0021, Japan
6. ⁶Department of Obstetrics and Gynaecology, Jichi Medical College, Kawachi-gun, Tochigi 329-0498, Japan
7. ⁷Department of Obstetrics and Gynaecology, Tottori University, Yonago, Tottori 683-8504, Japan
8. ⁸Department of Gynaecology, Kobe National Hospital, Kobe, Hyogo 554-0155, Japan
9. ⁹Department of Pathology II, National Defence Medical College, Tokorozawa, Saitama 359-8513, Japan
10. ¹⁰Department of Pathology, Tohoku University Hospital, Aoba-ku, Sendai 980-8574, Japan
11. ¹¹Department of Obstetrics and Gynaecology, Iwate Medical College, Morioka, Iwate 020-8505, Japan

Correspondence: Dr M Takano, Institute of Reproductive and Developmental Biology (IRDB), Imperial College of London, Hammersmith Hospital, DuCane Road, London W12 0NN, London, UK. E-mail: m.takano@imperial.ac.uk

Received 27 January 2006; Revised 24 March 2006; Accepted 27 March 2006; Published online 25 April 2006.

Abstract

A retrospective analysis was performed to evaluate the clinical characteristics and prognostic factors in the patients with clear cell carcinoma (CCC) of the ovary. After central pathological review and scanning of the medical records of nine Japanese institutions between 1992 and 2003, a total of 254 patients with CCC of the ovary were enrolled in the present study. Mean age was 52.4 years (range 23–73 years). Tumours were 13% (33/254) stage Ia, 36% (92/254) stage Ic, 13% (33/254) stage II, 30% (80/254) stage III, and 6% (16/254) stage IV. Five-year progression-free survival and overall survival was 84 and 88% in stage I, 57 and 70% in stage II, 25 and 33% in stage III and 0 and 0% in stage IV, respectively. Retroperitoneal lymph node metastasis was observed in 9% in pT1a tumours, 7% in pT1c tumours, 13% in pT2 tumours, and 58% in pT3 tumours, respectively. There was no survival benefit according to chemotherapeutic differences in the patients who received complete surgical staging procedures and conventional chemotherapy. Peritoneal cytological status was an independent prognostic factor in stage Ic patients (P=0.03) and only residual tumour diameter was an independent prognostic factor in stage III, IV patients (P=0.02). Our results suggest that cytoreductive surgery resulting in no residual tumour only could improve the prognosis of advanced CCC patients.