The prognostic role of maximum tumor dissemination derived by PET/CT in oncological diseases: a systematic review

Background/Objectives: Maximum tumor dissemination (Dmax) measured by positron-emission tomography/computed tomography (PET/CT) is a semiquantitative parameter recently introduced with potential prognostic role in several oncological diseases. It is defined as a three-dimensional feature that represents the maximal distance between the two farthest hypermetabolic PET lesions. The aim of our systematic review is to investigate the effective role of Dmax in the management of oncological patients. Methods: The current systematic review was carried out following a preset protocol, and the "Preferred Reporting Items for a Systematic Review and Meta-Analysis" served as a guideline for its development. A comprehensive search of the PubMed/MEDLINE, Embase and Cochrane library databases was conducted until August 2025. Results: A total of 37 studies were included in our research. Lymphoma was the most frequent cancer investigated, followed by prostate cancer, lung cancer and breast cancer. Despite their heterogeneity, most studies showed a significant prognostic role of Dmax in predicting overall survival (OS) and progression free survival (PFS). The combination of Dmax with other PET features, especially MTV, seemed to be useful to stratify patients risk of relapse and/or death. Conclusions: Despite several limitations affecting this analysis, especially related to the heterogeneity of the studies included, PET/CT seems to have a prognostic impact in several oncological diseases, especially in lymphoma. However, few methodological issues still need to be solved before we can implement Dmax in clinical practice.