IntroductionFew studies have evaluated the effectiveness of interventions for distress during cancer diagnosis on clinical outcomes in a real-world setting. We aimed to evaluate whether routine information and psychosocial support to patients experiencing distress at the time of diagnosis could decrease the risk of mortality within 1 and 3 years after diagnosis. Material and methodsWe conducted a retrospective cohort study of 4880 newly diagnosed cancer patients who reported distress scores of ≥4 using the tablet or kiosk-based screening between July 2014 and December 2017 at a university-affiliated cancer center in Seoul, South Korea. We performed an emulated target trial with two groups: those that received information and psychosocial support and those that did not. Cox proportional hazards models were used to identify the associations between information and psychosocial support and all-cause mortality. ResultsOf all the patients, 16.6 % had routine information and psychosocial support. The hazard ratio (HR) for one-year mortality comparing participants with information and psychosocial support to those without it were 0.73 (95 % confidence interval (CI) = 0.54, 0.99). Age < 50 and 50 - <60 group had a stronger effect of information and psychosocial support on reducing mortality within one-year than these in age ≥ 60 (p for interaction = 0.03). In terms of three-year mortality, the HR comparing participants with information and psychosocial support to those without it was 0.93 (95 % CI = 0.76, 1.14). ConclusionThis large-scale real-world study suggests that timely psychosocial care benefits newly diagnosed cancer patients who had distress during pre-treatment period.