Thirty-Day Mortality Following Systemic Anticancer Therapy: Evaluating Risk Factors Without Selection Bias in a Real-World, Population-Based Cohort From 2009 to 2019

AIMS: Risk factors for systemic anticancer therapies (SACTs) administered close to death derived from existing quality indicators are not directly applicable in the clinic, because they condition on future events, which leads to selection bias. This study aimed to adapt a previously suggested indicator for its use in a clinical context and to evaluate it in a real-world, population-based cohort of cancer patients.

MATERIALS AND METHODS: An improved version of the '30-day mortality after SACT' indicator suggested by Wallington et al. (Lancet Oncol 2016; 17:1203-16) was defined. All SACTs (n = 16 622) for all patients (n = 10 213) treated for common malignancies between 2009 and 2019 in the North Denmark Region were included. The results for the improved and Wallington's indicators were calculated and compared.

RESULTS: Overall, the association between clinical variables and 30-day mortality following SACT was similar for both indicators, except for the 75+ years age group. However, Wallington's indicator showed varying absolute risk when comparing values for quarterly and yearly observation intervals. The improved and Wallington's indicators showed large differences between curative (1.0% and 1.1%, respectively) and palliative SACTs (9.1% and 11.7%, respectively). For palliative SACTs, different types of malignancy presented with large variations for the improved indicator, ranging from above 10% for gastroesophageal, pancreatic and lung cancers to below 4% for prostate cancers. The value of the improved indicator was significantly lower in the last years of the study period compared with the 2009-2011 period. The type of malignancy was also associated with significant differences.

CONCLUSIONS: We defined an indicator adapted to the clinical context evaluating 30-day mortality following SACT. This indicator can be used to identify risk factors to help with clinical decision-making. A significant downward trend was observed in the 30-day mortality following palliative SACT over an 11-year period.