Case-mix adjustment to compare hospital performances regarding complications after cytoreductive surgery for ovarian cancer: a nationwide population-based study.

OBJECTIVE: Complication rates after cytoreductive surgery are important quality indicators for hospitals that treat patients with advanced-stage ovarian cancer. Case-mix factors are patient and tumor characteristics that may influence hospital outcomes such as the complication rates. Currently, no case-mix adjustment model exists for complications after cytoreductive surgery; therefore, it is unclear whether hospitals are being compared correctly. This study aims to develop the first case-mix adjustment model for complications after surgery for advanced-stage ovarian cancer, enabling an accurate comparison between hospitals. METHODS: This population-based study included all patients undergoing cytoreductive surgery for advanced-stage ovarian cancer registered in the Netherlands in 2017-2019. Case-mix variables were identified and assessed using logistic regressions. The primary outcome was the composite outcome measure 'complicated course'. Patients had a complicated course when at least one of the following criteria were met: (1) any complication combined with a prolonged length of hospital stay; (2) complication requiring reintervention; (3) any complication with a prolonged length of stay in the intensive care unit; or (4) 30-day mortality or in-hospital mortality during admission following surgery. Inter-hospital variation was analyzed using univariable and multivariable logistic regressions and visualized using funnel plots. RESULTS: A total of 1822 patients were included, of which 10.7% (n=195) had a complicated course. Comorbidity and tumor stage had a significant impact on complicated course rates in multivariable logistic regression. Inter-hospital variation was not significant for case-mix factors. Complicated course rates ranged between 2.2% and 29.1%, and case-mix adjusted observed/expected ratios ranged from 0.20 to 2.67 between hospitals. Three hospitals performed outside the confidence intervals for complicated course rates. These hospitals remained outliers after case-mix adjustment. CONCLUSION: There is variation between hospitals regarding complicated course rates after cytoreductive surgery for ovarian cancer in the Netherlands. While comorbidity and tumor stage significantly affected the complicated course rates, adjusting for case-mix factors did not significantly affect hospital outcomes. The limited impact of case-mix adjustment could be a result of the Dutch centralized healthcare model.

Guideline adherence in ovarian cancer for surgical staging in the Netherlands.

OBJECTIVE: Previous studies have shown low adherence to surgical staging guidelines in patients with clinical early-stage ovarian carcinoma. The aim of this study was to identify guideline adherence for surgical staging and to show the distribution of each surgical item within the study population. In addition, we examined whether regional variation in the Netherlands exists for complete surgical staging. METHODS: Patients with ovarian cancer and surgical staging registered in the Dutch Gynecological Oncology Audit between January 1, 2015 and December 31, 2019 in the Netherlands were included. Complete surgical staging was defined according to the Dutch evidence-based guideline. Surgical items were ranked and illustrated. Variation in complete surgical staging for eight regional cancer networks was shown in funnel plots. Manual validation of registered data was performed in three gynecological oncology centers. RESULTS: 604 patients underwent surgical staging, 365 (60%) underwent an incomplete staging procedure, 295 (81%) were registered with early-stage disease (International Federation of Gynecology and Obstetrics I-IIA) and, of these patients, 115 (39%) received adjuvant chemotherapy. Patients with incomplete surgical staging were operated more often with minimal invasive techniques (laparoscopy or robot) compared with patients in the complete staging group (p<0.001). Sampling of cytology/ascites was the most frequently lacking factor (29%). Manual validation of data in three gynecological oncology centers identified reasons for incomplete staging, the most common being 'perioperative findings' such as dense adhesions between tumor and peritoneum, consistent with advanced stage disease (≥IIA). Regional variation for complete surgical staging showed two regions performing outside the confidence intervals (12.5% and 25.5%, mean 40%). CONCLUSION: Guideline adherence for staging was lower than expected and validation of data gave additional insights into the reasons that were contributing to incomplete surgical staging. Moreover, this analysis showed that regional variation for surgical staging exists, which forms a starting point to improve and harmonize staging procedures for these patients nationwide.

NADP+ -dependent IDH1 R132 mutation and its relevance for glioma patient survival.

The isocitrate dehydrogenase 1 (IDH1) mutation occurs in high frequency in glioma and secondary glioblastoma (GBM). Mutated IDH1 produces the oncometabolite 2-hydroxyglutarate rather than α-ketoglutarate or isocitrate. The oncometabolite is considered to be the major cause of the association between the IDH1 mutation and gliomagenesis. On the other hand, the IDH1 mutation in GBM is associated with prolonged patient survival. This association is not well understood yet but IDH1 involvement in epigenetic silencing of O-6-methylguanine-DNA methyltransferase (MGMT), a DNA repair enzyme is considered to be an important mechanism. However, it was shown recently that the IDH1 mutation and MGMT silencing are independent prognostic factors. Here, we hypothesize that the IDH1 mutation reduces the capacity to produce NADPH and thus reduces the capacity to scavenge reactive oxygen species that are generated during irradiation and chemotherapy. IDH1 activity is responsible for two-thirds of the NADPH production capacity in normal brain, whereas the IDH1 mutation reduces this capacity by almost 40%. Therefore, we hypothesize that the reduced NADPH production capacity due to the IDH1 mutation renders GBM cells more vulnerable to irradiation and chemotherapy thus prolonging survival of the patients.