Influence of histological subtypes on the risk of an invasive recurrence in a large series of stage I borderline ovarian tumor including 191 conservative treatments

Background: The overall prognosis of stage I borderline ovarian tumors (BOT) is excellent but a small percentage of patients die to their disease. The prognostic factors for such a rare event are still not clearly defined. The aim of this study was to determine these factors for recurrence per se and recurrence in the form of invasive carcinoma in a large series of stage I tumors. Methods: A retrospective review of patients with BOT. Three inclusion criteria were defined: (i) a centralized histological review; (ii) macroscopic stage I tumors; (iii) exclusion of metastatic disease to the ovaries. Results: From 2000 to 2010, 254 patients fulfilled inclusion criteria [140 had mucinous BOT (MBOT) and 114 a serous BOT (SBOT)], and 191 had undergone conservative management. After a median follow-up of 45 months, 43 patients had developed recurrences (31 borderline and 12 invasive). The risks of recurrences were statistically increased after conservative treatment, particularly after a cystectomy, in patients with stage IB and among patients with incompletely staged tumors. In the subgroup of conservatively treated patients (representing 75% of our population), the risks of recurrences were statistically increased in patients affected by a SBOT, in patients who had undergone a cystectomy, in patients with stage IB disease and in patients with a micropapillary pattern (MPP). MBOT and the presence of a MPP were identified as prognostic factors for invasive disease. Conclusions: In the present series of BOT with the largest number of patients treated conservatively to date, the presence of a MPP and the mucinous subtype were associated with a higher rate of progression to carcinoma after conservative management. These important results suggest that MBOT belong to a ‘high-risk’ group likely to develop an invasive recurrence after fertility-sparing surgery in stage I BOT.