Objective: Peritoneal metastases (PM) are a challenge in gynecological cancers, but its appearance has never been described in a population-based study. Therefore, we describe the incidence of PM and identify predictors that increase the probability of peritoneal spread. Methods: All ovarian, endometrial and cervical cancer patients diagnosed in the Netherlands between 1989 and 2015 were identified from the Netherlands Cancer Registry and stratified for PM. Crude and age-adjusted incidence over time was calculated. Independent predictors for PM were identified using uni- and multivariable analyses. Results: The 94,981 patients were diagnosed with ovarian, endometrial or cervical cancer and respectively 61%, 2% and 1% presented with PM. Predictors for PM in ovarian cancer were: age between 50 and 74 years (odds ratio [OR]=1.19; 95% confidence interval [CI]=1.08–1.32), other distant metastases (OR=1.25; 95% CI=1.10–1.41), poor differentiation grade (OR=2.00; 95% CI=1.73–2.32) and serous histology. Predictors in endometrial cancer were lymph node metastases (OR=2.32; 95% CI=1.65–3.26), other distant metastases (OR=1.38; 95% CI=1.08–1.77), high-grade tumors (OR=1.95; 95% CI=1.38–2.76) and clear cell (OR=1.49; 95% CI=1.04–2.13) or serous histology (OR=2.71; 95% CI=2.15–3.42). In cervical cancer, the risk is higher in adenocarcinoma than in squamous cell carcinoma (OR=4.92; 95% CI=3.11–7.79). Conclusion PM are frequently seen in patients with ovarian cancer. In endometrial and cervical cancer PM are rare. Histological subtype was the strongest predictive factor for PM in all 3 cancers. Better understanding of predictive factors for PM and thus the biological behavior is of paramount importance.

Objective: The aim of this study was to assess the SLN detection rate in presumed early stage, low- and intermediate-risk endometrial cancers, the incidence of SLN metastases, and the negative predictive value of SLN mapping performed with indocyanine green (ICG). Methods: A systematic review with meta-analyses was conducted. Study inclusion criteria were A) low- and intermediate-risk endometrial cancer, B) the use of ICG per cervical injection; C) a minimum of twenty included patients per study. To assess the negative predictive value of SLN mapping, D) a subsequent lymphadenectomy was an additional inclusion criterion. Results: Fourteen studies were selected, involving 2,117 patients. The overall and bilateral SLN detection rates were 95.6% (95% confidence interval [CI]=92.4%–97.9%) and 76.5% (95% CI=68.1%–84.0%), respectively. The incidence of SLN metastases was 9.6% (95% CI=5.1%–15.2%) in patients with grade 1–2 endometrial cancer and 11.8% (95% CI=8.1%–16.1%) in patients with grade 1–3 endometrial cancer. The negative predictive value of SLN mapping was 100% (95% CI=98.8%–100%) in studies that included grade 1–2 endometrial cancer and 99.2% (95% CI=97.9%–99.9%) in studies that also included grade 3. Conclusion SLN mapping with ICG is feasible with a high detection rate and negative predictive value in low- and intermediate-risk endometrial cancers. Given the incidence of SLN metastases is approximately 10% in those patients, SLN mapping may lead to stage shifting with potential therapeutic consequences. Given the high negative predictive value with SLN mapping, routine lymphadenectomy should be omitted in low- and intermediate-risk endometrial cancer.