Overall survival following implementation of clinical pathways for cancer care

328 Background: Clinical pathways are decision support tools designed to enhance accessibility and ease of use of treatment recommendations. Prior studies that evaluated cancer clinical pathways largely focused on process measures such as concordance with treatment guidelines, but little evidence is available about the effect of clinical pathways on survival. We thus aimed to evaluate the effect of cancer clinical pathways on overall survival. Methods: We used institutional registry data from the JPS Oncology and Infusion Center, which is a Comprehensive Community Cancer Program. Eligible patients were aged ≥18 years, diagnosed with first primary breast, colorectal, or lung cancer between December 2013 and December 2017 with follow-up through June 2020. We used a natural experiment framework, where intervention was implementation of clinical pathways (December 2015). The pre-intervention period was December 2013 – November 2015 and post-intervention period was January 2016 – December 2017. We used marginal structural models with stabilized inverse probability weights for each cancer type to estimate restricted mean survival time (RMST) differences and 95% confidence limits (CL) comparing overall survival between pre- and post-clinical pathways within a 36-month horizon, where weights were based on a minimal sufficient set of covariates (sociodemographics, tumor characteristics, and comorbidities) to reduce confounding bias. Results: Our study population comprised 327 breast, 254 colorectal, and 431 lung cancer patients. Median age ranged between 55 years (breast) and 60 years (lung). The frequency of racial/ethnic minorities ranged between 45% (lung) and 68% (colorectal). The frequency of uninsured patients ranged between 47% (lung) and 58% (colorectal). Adherence to pathways was consistently over 80%. RMST was largely similar between pre- and post-clinical pathways for breast (RMST difference = -0.10 months, 95% CL: -1.9, 1.7), colorectal (RMST difference = -0.48 months, 95% CL: -3.4, 2.5) and lung cancer (RMST difference = 1.1 month, 95% CL: -1.5, 3.7). Conclusions: Our results suggest that implementation of clinical pathways has minimal effect on overall survival within 36 months despite high adherence in a safety-net population, but the estimates are compatible with up to 3.4 month decrease or 3.7 month increase depending on cancer type. Longer follow-up, particularly for breast and colorectal cancer, may provide further insight. Our findings may be useful for informing deliberations about implementing clinical pathways and setting expectations about the effect of clinical pathways on overall survival.