Tohoku J. Exp. Med., 2013 August, 230(4)

Yolk Sac Tumor of the Ovary: A Retrospective Multicenter Study of 33 Japanese Women by Tohoku Gynecologic Cancer Unit (TGCU)

TAKANOBU KOJIMAHARA,¹ KENJI NAKAHARA,¹ TADAO TAKANO,² NOBUO YAEGASHI,² HIROSHI NISHIYAMA,³ KEIYA FUJIMORI,³ NAOKI SATO,⁴ YUKIHIRO TERADA,⁴ TORU TASE,⁵ YOSHIHITO YOKOYAMA,⁶ HIDEKI MIZUNUMA,⁶ TADAHIRO SHOJI,⁷ TORU SUGIYAMA⁷ and HIROHISA KURACHI¹

¹Department of Obstetrics and Gynecology, Yamagata University Faculty of Medicine, Yamagata, Yamagata, Japan
²Department of Gynecology and Obstetrics, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
³Department of Obstetrics and Gynecology, Fukushima Medical University School of Medicine, Fukushima, Fukushima, Japan
⁴Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Akita, Japan
⁵Department of Gynecology, Miyagi Cancer Center, Natori, Miyagi, Japan
⁶Department of Obstetrics and Gynecology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
⁷Department of Obstetrics and Gynecology, Iwate Medical University School of Medicine, Morioka, Iwate, Japan

Yolk sac tumor (YST) of the ovary is a rare germ cell tumor comprising about 1% of all ovarian malignancies. YST usually occurs as a rapidly growing unilateral tumor in young women. With the introduction of cisplatin, YST has been changed from a fatal tumor to a curable tumor. The standard treatment of YST consists of fertility-preserving surgery and 3 or 4 courses of adjuvant combination chemotherapy with bleomycin, etoposide, and cisplatin (BEP). However, the long-term prognosis of BEP-treated YST patients has not been well studied. We therefore conducted a retrospective multicenter study to investigate the prognostic factors of 33 YST patients, including 25 patients treated with BEP. The median age at initial treatment was 20 years (range 10-53). There were 15 patients (at stage I), one (stage II), 16 (stage III), and one (stage IV). Nominal and grouped numerical values were analyzed by the Kaplan-Meier method. All patients had unilateral tumor, with right-side predominance (23 patients; P = 0.02). Eighteen patients had pure YST, 13 had mixed germ cell tumor with YST component, and other 2 patients were not specified. Twenty-eight patients received fertility-preserving surgery. Twenty-seven patients had optimal surgery with less than 1 cm residual tumor diameter. Median number of chemotherapy courses was 5. Median follow-up period was 49 months. The cumulative 5-year survival rate was 87%. Univariate analysis revealed the following significant prognostic factors (P < 0.05): stage, tumor diameter, and residual tumor. Extensive debulking surgery to minimize residual tumor would improve the prognosis.

keywords —— bleomycin; cisplatin; etoposide; retrospective study; yolk sac tumor

© 2013 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2013, 230, 211-217

Correspondence: Takanobu Kojimahara, Department of Obstetrics and Gynecology, Yamagata University School of Medicine, 2-2-2 Iidanishi, Yamagata, Yamagata 990-9585, Japan.

e-mail: tkojimah@med.id.yamagata-u.ac.jp