Serous and mucinous borderline ovarian tumours: differences in clinical presentation, high-risk histopathological features, and lethal recurrence rates

Background: Mucinous and serous borderline ovarian tumours (mBOTs and sBOTs) are controversial diseases.

Objectives: With this systematic review we aim to evaluate the different high-risk histopathological features and recurrence rates.

Search strategy: The PubMed database was searched using two terms: {serous AND [(borderline) OR (low malignant potential)] AND ovarian AND tumour} and {mucinous AND [(borderline) OR (low malignant potential)] AND ovarian AND tumour}.

Selection criteria: Cohorts of either sBOT or mBOT, peer-reviewed, retrospective, or prospective.

Data collection and analysis: Lethal recurrence data for micropapillary patterns (MPs), microinvasion, non-invasive and invasive implants, and intraepithelial carcinoma (IECA). The primary measure of effect was the odds ratio of lethal recurrence reduction.

Results: Data from patients in 42 studies including 4414 sBOTs and 12 studies including 894 mBOTs were pooled. Of these, 53.3% presented early-stage typical sBOTs, 24.4% presented with MPs, 22.3% presented with microinvasion, 34.4% presented with non-invasive implants, and 7.3% presented with invasive implants. The pooled lethal recurrence rates were, respectively: 18.3, 16.8, 10.7, 16.2, and 33.8%. Patients with MPs were more likely to suffer lethal recurrence when compared with high-stage sBOTs (odds ratio, OR 0.501; P = 0.003), whereas the trend in microinvasive sBOTs did not reach statistical significance. Regarding mBOTs, 61.6% presented with early-stage typical mBOTs, 19.6% presented with microinvasion, 34.8% presented with IECA, and six patients presented with non-invasive implants; none presented with invasive implants. The lethal recurrence rates were, respectively: 3.6, 0, 3.7, and 0%.

Conclusion: Micropapillary patterns (MPs) showed a higher risk for lethal recurrence when compared with high-stage sBOTs. Regarding mBOTs, IECA and microinvasion do not play a role in the lethal recurrence rate.

Tweetable abstract: Micropapillary pattern confirmed as high-risk in BOT. IECA and microinvasion don't play a role in mucinous BOT.