Clinical impact of under-diagnosis by frozen section examination is minimal in borderline ovarian tumors

Aims: The purpose of this study was to examine the clinical impact of under-diagnosis by frozen section examination in borderline ovarian tumors (BOTs). Methods: We reviewed 209 consecutive patients with BOTs who were diagnosed and treated at our institute between March 1988 and July 2007. Tumors from 182 of 209 patients were evaluated by frozen section examination. After excluding a case with a deferred diagnosis, the results of frozen section examinations were compared with the final paraffin section examination. In 61 patients, the frozen section examination under-diagnosed a BOT as a benign tumor. In 120 patients, the frozen section examination correctly diagnosed or over-diagnosed it BOT. The clinical impact of under-diagnosis was evaluated by comparing the extent of surgery and treatment outcome between the patients who were under-diagnosed (study group) and the patients who were not under-diagnosed (control group). Results: The study group had more mucinous (P = 0.03) and/or stage 1A (P = 0.02) tumors than the control group. Fewer patients in the study group received adjuvant chemotherapy than the patients in the control group (P = 0.02). Fewer patients in the study group underwent radical surgery than the patients in the control group (P = 0.02). However, the rates of treatment failure were similar between the two groups (no treatment failure in the study group and seven treatment failures in the control group; P = 0.10). Conclusions: The under-diagnosis by frozen section examination did not compromise the outcome in patients with BOTs, although under-diagnosis was associated with more conservative surgery. (C) 2009 Elsevier Ltd. All rights reserved.