Abstract Introduction: Treatment of locally advanced rectal cancer (LARC) using neoadjuvant chemoradiotherapy (nCRT) improves local control and survival, but response varies. Patients treated at the Institute for Oncology and Radiology of Serbia (IORS) who undergo surgery upon complete response might be exposed to risks and poor quality of life. A consortium dedicated to redefining prognostic and predictive biomarkers in rectal cancer was formed within the framework of the STEPUPIORS Horizon Europe project. The current study evaluated whether employing collaborative widening funds might lead to sustainable strategies for cancer treatment, lowering inequity and steering societal impact, especially in countries with limited resources, using a pilot rectal cancer project. Patients and Methods: The analysis was performed in the period Oct 01, 2022, to Oct 01, 2023, with a Serbian coordinating institution and partners from Spain, Greece, and the Netherlands as expert twinning centers. RT was administered to 75 patients with LARC using volumetric modulated arc therapy-simultaneous integrated boost approach/concomitant chemotherapy (5FU/Leucovorin, week 1&5) for the first time in Serbia. A comprehensive approach towards building human capacities on biobanking, multiomics analyses and project management was developed through intensive training and expert visits. Consensus consortium decisions were reached on regular partner meetings. Results: Patients with clinical complete response (16.0%) and initially distant-located tumors were enrolled in the watch and wait approach and are under follow up. Developed pipelines for multiomics analyses led to 4 high-quality papers on new predictive biomarkers to nCRT in LARC and the deposition of omics data in open-science repositories following FAIR data principles. A first Serbian cancer biobank was successfully installed. Fifteen IORS researchers (87% female), were certified in biobanking. A grant management office was established to provide and support the sustainability of future research projects. This led to 5 new grant applications and enrollment of 1 female project member in a Masters program for Management in the Health Care System. Conclusion: This study showed that even within the first 12 months, implementation of a 3-year collaborative grant dedicated to a specific research problem, might significantly change educational and treatment strategies enabling better patient care (OCEBM level of evidence 3). The results highlight that disparities in cancer outcomes and health equity might only be addressed by progressing beyond descriptions of said outcomes and taking specific action. Systematic, long-term strategic initiatives and collaborations among relevant stakeholders and ethical, legal and societal structures are needed in more countries. Acknowledgements: Horizon Europe Project STEPUPIORS (101079217). Citation Format: Milena Cavic, Ana Djuric, Mladen Marinkovic, Aleksandra Stanojevic, Miljana Tanic, Snezana Bjelogrlic, Jelena Spasic, Ana Damjanovic, Marija Djordjic Crnogorac, Ana Vuletic, Katarina Mirjacic Martinovic, Marko Radulovic, Suzana Stojanovic-Rundic, Ana Krivokuca, Radmila Jankovic, Sergi Castellvi-Bel, Jerome Zoidakis, Remond J. Fijneman. Employing widening funds to address inequity in cancer research - example of the STEPUPIORS collaborative rectal cancer project [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1304.