Novel methods to define invasive procedures at the end of life were developed to improve quality of end of life care research: a population-based cohort study in colorectal cancer.

BACKGROUND: Understanding the use of invasive procedures (IPs) at the end of life (EoL) is important to avoid undertreatment and overtreatment, but epidemiologic analysis is hampered by limited methods to define treatment intent and EoL phase. This study applied novel methods to report IPs at the EoL using a colorectal cancer case study. METHODS: An English population-based cohort of adult patients diagnosed between 2013 and 2015 was used with follow-up to 2018. Procedure intent (curative, noncurative, diagnostic) by cancer site and stage at diagnosis was classified by two surgeons independently. Joinpoint regression modeled weekly rates of IPs for 36 subcohorts of patients with incremental survival of 0-36 months. EoL phase was defined by a significant IP rate change before death. Zero-inflated Poisson regression explored associations between IP rates and clinical/sociodemographic variables. RESULTS: Of 87,731 patients included, 41,972 (48%) died. Nine thousand four hundred ninety two procedures were classified by intent (inter-rater agreement 99.8%). Patients received 502,895 IPs (1.39 and 3.36 per person year for survivors and decedents). Joinpoint regression identified significant increases in IPs 4 weeks before death in those living 3-6 months and 8 weeks before death in those living 7-36 months from diagnosis. Seven thousand nine hundred eight (18.8%) patients underwent IPs at the EoL, with stoma formation the most common major procedure. Younger age, early-stage disease, men, lower comorbidity, those receiving chemotherapy, and living longer from diagnosis were associated with IPs. CONCLUSION: Methods to identify and classify IPs at the EoL were developed and tested within a colorectal cancer population. This approach can be now extended and validated to identify potential undertreatment and overtreatment.