Consensus statements on the definition, diagnosis, and management of oligoprogressive disease: results of an expert survey of Kazakhstan Cancer Society.

Aim: Oligoprogressive disease (OPD) has emerged as a clinically relevant and common scenario in oncology, reflecting progression in a limited number of metastatic sites while systemic therapy continues to control the majority of disease. Despite its increasing recognition, the definition, diagnostic approach, and management of OPD remain poorly standardized. Methods: A multidisciplinary expert panel from Kazakhstan and international faculty, including ten medical oncologists, radiation, and surgical oncologists, participated in a structured survey. The questionnaire consisted of 15 items divided into three domains: definition of OPD, diagnostic evaluation, and treatment strategies. Responses were analyzed, and consensus was defined as ≥ 70% agreement, relative agreement as 50-69%, and lack of consensus as < 50%. Results: Consensus was reached that OPD is defined as progression in a limited number of lesions while other sites remain controlled, regardless of lesion size or localization. No consensus was achieved regarding the maximum number of progressive lesions, with experts divided between "≤ 5 lesions" and "any number amenable to local therapy." Imaging with CT or PET-CT was considered sufficient. Biopsy and molecular testing were recommended only in selected contexts. Systemic therapy continuation during OPD was endorsed if effective, with strong support for local therapy, particularly stereotactic ablative radiotherapy (SBRT/SABR). Divergence remained regarding the management of repeat OPD. Conclusions: This Kazakhstan Cancer Society consensus defines the fundamental clinical features of OPD and provides practical recommendations for diagnosis and treatment. Comparison with international guidelines reveals broad alignment on systemic continuation and local therapy, as well as persistent variation regarding lesion number, biopsy, and repeat OPD management.