Cancer stage at diagnosis by duration of pre-existing chronic analgesic use and anxiety or depression.

Pre-existing chronic diseases may delay or expedite cancer diagnosis. Here, we examine variations in cancer stage at diagnosis based on duration and type of common chronic conditions. We identify lung and colon cancers diagnosed 2012-2018 from national cancer registration, and pre-existing physical and mental-health conditions from linked primary care records. Using multivariable logistic regression, we explore associations between the most prevalent conditions (Anxiety/Depression and Chronic Analgesic Medication use), classified as "Recent-onset" (first recorded <12months pre-cancer) or "Persistent/Historic" (12-72 months pre-cancer), and cancer stage at diagnosis. We show that recent-onset Analgesic Medication use can be associated with increased odds of advanced stage lung or colon cancer diagnosis. Conversely, persistent/historic Chronic Analgesic Medication use can be associated with reduced odds of advanced stage lung cancer and persistent/historic Anxiety/Depression with reduced odds of advanced stage lung or colon cancer. Persistent or historic conditions may increase healthcare utilisation, offering opportunities for early cancer diagnosis. Recent-onset conditions may lead to delays through the alternative explanations or competing demands mechanisms.