e23179 Background: Cancer treatments, despite increasing effectiveness, involve significant short and long-term side effects profoundly impacting a person's quality of life (QoL). In response, Advocates for Collaborative Education, a global coalition of patient advocates, initiated an exempt, online survey to gather insights on the perceived QoL impact of cancer diagnosis and treatment. The effort sought to identify community priorities and hopes to guide improvements in supportive care. Methods: A comprehensive survey, developed by patients, survivors, and advocates, comprised six sections and 93 questions. Co-creation played a vital role in determining relevant categories, questions, and measurement scales to assess severity and impact of QoL challenges. The study requested demographic and cancer diagnosis data before inquiring about 17 treatment-related side effects, their perceived severity, preparation, unintended side effects of supportive care, and personal preferences for cancer-related information. Recruitment was conducted via social media. Results: The survey garnered responses from 515 individuals with a history of cancer and a wide range of demographic subsets, including age, race, stage of cancer, and treatment modalities. Survey respondents reported an average pre-diagnosis QoL score of 8.87 out of 10, which declined to a mean score of 6.41 post-diagnosis. Across all cancer types, physical well-being was a top priority for most respondents (51.5%), followed by emotional well-being (25.4%). Across a variety of side effects, unintended consequences of side effect treatments were highlighted, revealing complexities in supportive care. Detailed results for all categories and stratification by subsets of age, race, metastatic vs. early stage, treatment type, and others are available for presentation and publication purposes. Conclusions: This study highlights the significant negative impact of cancer treatment on an individual's QoL, addressing an underexplored area of cancer research. While managing treatment side effects is crucial, supportive therapies may introduce additional side effects, exacerbating an overall burden on patients. The collaborative survey development with patients and survivors represents a pivotal step, offering valuable insights for enhancing the well-being of individuals affected by cancer. [Table: see text]