Trends in Volume, Timeliness, and Reporting Quality of Oncology Systematic and Scoping Reviews: A 25-Year Analysis

Systematic and scoping reviews synthesize evidence in oncology's fast-moving therapeutic landscape, informing clinical and policy decisions. However, little is known about how review volume has changed over time, how quickly reviews reach publication, or how often protocol registration is reported within review abstracts. We searched Medline (PubMed), Embase, and the Cochrane Library (2000 to 9 October 2025) for oncology-focused articles labelled as systematic or scoping reviews, screened in duplicate by a human reviewer and a ChatGPT-5-assisted system, with a third reviewer resolving disagreements. Cancer subspecialty, search-to-publication interval, and abstract-level protocol registration status and registry type were extracted. Of 92,800 references, 49,378 (53%) were systematic (n = 46,318) or scoping (n = 3060) reviews. Review volume rose sharply from 2000 (n = 61) to 2024 (n = 6313), with scoping reviews increasing steadily. Data for 2025 were available only through 9 October and were therefore not directly comparable with prior complete years. Among 9297 reviews reporting search dates, mean search-to-publication lag was 13 months, unchanged over time (p = 0.09). Only 2235 reviews (4.5%) reported protocol registration in their abstract, predominantly via the International Prospective Register of Systematic Reviews (PROSPERO). Oncology evidence-synthesis output has grown, yet publication timeliness and abstract-level registration reporting have not improved, raising questions about its currency and verifiability.