To identify clinicopathologic factors predictive of early relapse (platinum-free interval (PFI) of ≤6 months) in advanced epithelial ovarian cancer (EOC) in first-line treatment, and to develop and internally validate risk prediction models for early relapse. All consecutive patients diagnosed with advanced stage EOC between 01-01-2008 and 31-12-2015 were identified from the Netherlands Cancer Registry. Patients who underwent cytoreductive surgery and platinum-based chemotherapy as initial EOC treatment were selected. Two prediction models, i.e. pretreatment and postoperative, were developed. Candidate predictors of early relapse were fitted into multivariable logistic regression models. Model performance was assessed on calibration and discrimination. Internal validation was performed through bootstrapping to correct for model optimism. A total of 4,557 advanced EOC patients were identified, including 1,302 early relapsers and 3,171 late or non-relapsers. Early relapsers were more likely to have FIGO stage IV, mucinous or clear cell type EOC, ascites, >1 cm residual disease, and to have undergone NACT-ICS. The final pretreatment model demonstrated subpar model performance (AUC = 0.64 [95 %-CI 0.62-0.66]). The final postoperative model based on age, FIGO stage, pretreatment CA-125 level, histologic subtype, presence of ascites, treatment approach, and residual disease after debulking, demonstrated adequate model performance (AUC = 0.72 [95 %-CI 0.71-0.74]). Bootstrap validation revealed minimal optimism of the final postoperative model. A (postoperative) discriminative model has been developed and presented online that predicts the risk of early relapse in advanced EOC patients. Although external validation is still required, this prediction model can support patient counselling in daily clinical practice.

Introduction: Epithelial ovarian cancer (EOC) patients undergoing splenectomy during cytoreductive surgery represent a small subgroup of patients. Splenic metastases or technical reasons due to extensive upper abdominal disease may require a splenectomy. It has been hypothesized that as the spleen’s antitumor immunologic functions may inhibit cancer growth, splenectomy may promote the growth of residual disease as observed in other cancer types of murine studies. The few studies assessing the impact of splenectomy on the oncologic outcomes of advanced stage EOC patients have reported inconsistent results. It remains unclear whether splenectomy during cytoreductive surgery is justified to achieve complete cytoreduction. The aim of this study was to assess the impact of a splenectomy on perioperative outcomes and survival of advanced stage EOC patients.Material and methods: In this nationwide population‐based study, all consecutive patients diagnosed with FIGO stage IIIC and IV EOC between 1 January 2008 and 31 December 2015 were identified from the Netherlands Cancer Registry. Patients who underwent cytoreductive surgery combined with platinum‐based chemotherapy as primary treatment were selected. Differences in clinicopathologic characteristics between splenectomy and non‐splenectomy patients were assessed. Progression‐free survival (PFS) and overall survival (OS) were analyzed using Kaplan–Meier survival curves and log‐rank tests. Cox proportional hazards models were used to adjust for covariates that influence survival.Results: A total of 3911 patients were identified: 99 splenectomy and 3812 non‐splenectomy patients. Splenectomy patients were more likely to undergo extensive surgery or surgical reintervention, to receive intraperitoneal chemotherapy, intraoperative and postoperative blood transfusion, to experience postoperative infections, and to be admitted to an intensive care unit (all p < 0.002). No significant differences in PFS or OS were observed between splenectomy vs non‐splenectomy patients after adjusting for covariates.Conclusions: Although advanced stage EOC patients who undergo splenectomy during cytoreductive surgery have less favorable perioperative outcomes, no adverse impact of splenectomy on the survival of advanced stage EOC patients was observed. Splenectomy during cytoreductive surgery seems to be justified to achieve complete cytoreduction in advanced stage EOC patients.

Objective: The sepsis-induced inflammatory response may potentially affect malignant cells. Recently, a case of spontaneous regression of a histologically confirmed International Federation of Gynecology and Obstetrics (FIGO) stage IIIC epithelial ovarian cancer (EOC) following sepsis was reported. The aim of our study was to assess the impact of sepsis on the oncologic outcomes of advanced-stage EOC patients. Methods: Gynecologic oncologic patients admitted to the Intensive Care Unit of three oncologic centers between 2006 and 2019 were identified and patients who experienced sepsis following advanced-stage EOC diagnosis were selected. Survival outcomes were compared with advanced-stage EOC patients from the Netherlands Cancer Registry (NCR). To correct for case-mix differences, propensity score matching using 1:3 nearest neighbor matching was conducted after which survival analyses were repeated. Results: A total of 18 of 215 patients with advanced-stage EOC experienced sepsis. Sepsis patients had similar distributions of patient, tumor, and treatment characteristics to 3988 patients from the NCR cohort. A total of 3 of 18 patients died from the complications of sepsis. While the remaining patients initially responded to treatment, 14/15 patients relapsed. The median (IQR) overall survival was 31 (24–44) and 35 (20–60) months for the sepsis and unmatched NCR cohort (p = 0.56), respectively. The median (IQR) progression-free survival was 16 (11–21) and 16 (11–27) months (p = 0.90), respectively. Survival outcomes did not differ following propensity matching (overall survival of 31 (24–44) vs. 36 (20–56) months, p = 0.40; progression-free survival of 16 (11–21) and 16 (12–21) months, p = 0.72). Conclusion: In this observational study, the occurrence of sepsis did not affect the oncologic and survival outcomes of advanced-stage EOC patients.

Objective: To assess the association between pretreatment thrombocytosis, anemia, and leukocytosis and overall survival (OS) of advanced-stage EOC. Furthermore, to develop nomograms using established prognostic factors and pretreatment hematologic parameters to predict the OS of advanced EOC patients. Methods: Advanced-stage EOC patients treated between January 1996 and January 2010 in eastern Netherlands were included. Survival outcomes were compared between patients with and without pretreatment thrombocytosis (≥450,000 platelets/µL), anemia (hemoglobin level of <7.5 mmol/L), or leukocytosis (≥11.0 × 10⁹ leukocytes/L). Three nomograms (for ≤3-, ≥5-, and ≥10-year OS) were developed. Candidate predictors were fitted into multivariable logistic regression models. Multiple imputation was conducted. Model performance was assessed on calibration, discrimination, and Brier scores. Bootstrap validation was used to correct for model optimism. Results: A total of 773 advanced-stage (i.e., FIGO stages IIB–IV) EOC patients were included. The median [interquartile range, IQR] OS was 2.3 [1.3–4.2] and 3.0 [1.4–7.0] years for patients with and without pretreatment thrombocytosis (p < 0.01). The median OS was not notably different for patients with and without pretreatment leukocytosis (p = 0.58) or patients with and without pretreatment anemia (p = 0.07). The final nomograms comprised established predictors with either pretreatment leukocyte or platelet count. The ≥5- and ≥10-year OS models demonstrated good calibration and adequate discrimination with optimism-corrected c-indices [95%-CI] of 0.76 [0.72–0.80] and 0.78 [0.73–0.83], respectively. The ≤3-year OS model demonstrated suboptimal performance with an optimism-corrected c-index of 0.71 [0.66–0.75]. Conclusions: Pretreatment thrombocytosis is associated with poorer EOC survival. Two well-performing models predictive of ≥5-year and ≥10-year OS in advanced-stage EOC were developed and internally validated.

Objective: Population-based information regarding adherence to first-line chemotherapy in epithelial ovarian cancer is scarce. This study aimed to evaluate chemotherapy adherence, reasons for chemotherapy modifications, and associations with overall survival. Methods: Advanced-stage epithelial ovarian cancer patients diagnosed between January 2015 and December 2021 were identified from the Netherlands Cancer Registry. Patients who underwent cytoreductive surgery combined with platinum- and taxane-based chemotherapy were included. Patients were categorized into two groups: adherent (patients without modifications) and non-adherent (patients with modifications: dose reduction, chemotherapy interruption, and/or reduction in chemotherapy cycles). Reasons for modifications were assessed. Kaplan-Meier survival curves and Cox proportional hazards models were used to analyze overall survival. Results: Among the cohort (N = 3,687), 54% of patients underwent chemotherapy modifications. Dose reduction (38%) was the most common, followed by interruption (24%) and reduction in chemotherapy cycles (9%). Non-adherence was associated with poorer performance scores, higher comorbidity indices, and undergoing primary cytoreductive surgery. Neurotoxicity and hematologic toxicity were the primary reasons for modifications in platinum (33% and 37%) and taxane (47% and 35%) agents. No association with survival was found for dose reduction and interruption. However, reduction in chemotherapy cycles was associated with lower 5-year overall survival (32% (95% CI 26%-38%) vs. 36% (95% CI 34%-38%)), remaining significant after multivariable adjustment (hazard ratio 1.36; 95% CI 1.17-1.59). Conclusion: A significant proportion of Dutch advanced-stage epithelial ovarian cancer patients undergo chemotherapy modifications. No impact on overall survival was found for dose reduction or chemotherapy interruption, warranting prospective studies. Reduction in chemotherapy cycles was negatively associated with overall survival, possibly reflecting underlying treatment ineffectiveness. Key messages: What is already known on this topic: Guideline-recommended chemotherapy for advanced epithelial ovarian cancer is often difficult to deliver in routine practice, and real-world data on adherence and its impact on survival are limited. What this study adds: In this nationwide retrospective cohort, over half of patients experienced chemotherapy modifications; dose reductions and interruptions were not associated with poorer overall survival, whereas a reduction in the number of cycles showed an association with worse outcomes, although this may partly reflect underlying disease severity or treatment response. How this study might affect research, practice or policy: Our findings suggest that standard dosing and treatment duration of six cycles may not always be necessary, emphasizing the need to tailor treatment plans to optimize both efficacy and tolerability in advanced-stage epithelial ovarian cancer patients

Population-based information on variation in the delivery of first-line chemotherapy for epithelial ovarian cancer is scarce. This study aimed to evaluate chemotherapy delivery, reasons for chemotherapy modifications, and their associations with overall survival. Patients with advanced-stage epithelial ovarian cancer diagnosed from January 2015 through December 2021 were identified in the Netherlands Cancer Registry. We included patients who underwent cytoreductive surgery with platinum- and taxane-based chemotherapy and categorized them as receiving chemotherapy without or with modifications (dose reduction, interruption, and/or fewer cycles). We assessed reasons for modifications and used Kaplan-Meier curves and Cox proportional hazards models to analyze overall survival. Among 3687 patients, 54% underwent chemotherapy modifications. Dose reduction (38%) was most common, followed by interruption (24%) and fewer cycles (9%). Patients with modifications more often had poorer performance scores, higher comorbidity indices, and primary cytoreductive surgery. Neurotoxicity and hematologic toxicity were the primary reasons for platinum (33% and 37%) and taxane (47% and 35%) modifications. Dose reduction and interruption were not associated with survival. Fewer cycles were associated with lower 5-year overall survival (32% [95% confidence interval 26% to 38%] vs 36% [95% confidence interval 34% to 38%]) after multi-variable adjustment (hazard ratio 1.36, 95% confidence interval 1.17 to 1.59). A substantial proportion of Dutch patients with advanced-stage epithelial ovarian cancer undergo chemotherapy modifications. Dose reduction and chemotherapy interruption did not appear to be associated with overall survival, warranting prospective studies. A reduction in the number of chemotherapy cycles was negatively associated with overall survival, possibly reflecting underlying treatment ineffectiveness. However, this association could also be explained by residual confounding (eg, underlying disease severity or treatment response not fully captured in our data) and warrants further confirmation.