Beyond post-operative readmissions: analysis of the impact of unplanned readmissions during primary treatment of advanced-stage epithelial ovarian cancer on long-term oncology outcome

Background Multiple studies have assessed post-operative readmissions in advanced ovarian cancer. Objective To evaluate all unplanned readmissions during the primary treatment period of advanced epithelial ovarian cancer, and the impact of readmission on progression-free survival. Methods This was a single institution retrospective study from January 2008 to October 2018. X 2 /Fisher's exact and t-test, or Kruskal-Wallis test were used. Multivariable Cox proportional hazard models were used to assess the effect of covariates in progression-free survival analysis. Results A total of 484 patients (279 primary cytoreductive surgery, 205 neoadjuvant chemotherapy) were analyzed. In total, 272 of 484 (56%; 37% primary cytoreductive surgery, 32% neoadjuvant chemotherapy, p=0.29) patients were readmitted during the primary treatment period. Overall, 42.3% of the readmissions were surgery related, 47.8% were chemotherapy related, and 59.6% were cancer related but not related to surgery or chemotherapy, and each readmission could qualify for more than one reason. Readmitted patients had a higher rate of chronic kidney disease (4.1% vs 1.0%, p=0.038). Post-operative, chemotherapy, and cancer-related readmissions were similar between the two groups. However, the percentage of inpatient treatment days due to unplanned readmission was twice as high for primary cytoreductive surgery at 2.2% vs 1.3% for neoadjuvant chemotherapy (p<0.001). Despite longer readmissions in the primary cytoreductive surgery group, Cox regression analysis demonstrated that readmissions did not affect progression-free survival (HR=1.22, 95% CI 0.98 to 1.51; p=0.08). Primary cytoreductive surgery, higher modified Frailty Index, grade 3 disease, and optimal cytoreduction were associated with longer progression-free survival. Conclusions In this study, 35% of the women with advanced ovarian cancer had at least one unplanned readmission during the entire treatment time. Patients treated by primary cytoreductive surgery spent more days during readmission than those with neoadjuvant chemotherapy. Readmissions did not affect progression-free survival and may not be valuable as a quality metric.