Abstract Background Patients required comprehensive cancer treatment in the community based on medical collaboration between designated cancer care hospitals and community medical and nursing care facilities to help them live life on their own terms. This study aims to describe the barriers to medical collaboration in community-based integrated care from the perspectives of healthcare providers (HCPs) and long-term care providers (LCPs) supporting cancer patients. Methods Semi-structured interviews were conducted with 88 HCPs and LCPs supporting cancer patients. We analyzed interview data to describe barriers to medical collaboration between designated cancer care hospitals and community medical and nursing care facilities using content analysis in MAXQDA. Results Participants were mostly HCPs, with physicians accounting for the largest proportion (27.3%). Totally, 299 codes were integrated into seven barriers to medical collaboration in community-based integrated care, including lack of information provision including life perspectives and a delay in sharing cancer patients’ values with HCPs to provide end-of-life care according to the patients’ wishes. Furthermore, insufficient coordination of cancer and non-cancer symptom management was identified as a barrier specific to older adults with cancer. Conclusions Barriers related to cancer treatment that integrate lifestyle perspectives, end-of-life care emphasizing patient values, and medical collaboration between cancer and non-cancer care are distinctive. They emphasize the importance of utilizing professionals to connect treatment and lifestyle information, establishing a central coordinating organization led by the DCCH, and developing a community palliative care network. Moreover, connecting cancer and non-cancer care through government and medical collaboration is crucial.