Guidelines move on, answers don't: with a strong model, retrieving several ASCO guideline versions made stale answers about four times as frequent as answering without retrieval
Oncology guidelines are revised as evidence emerges, so an answer can faithfully cite a real guideline and still cite a superseded version. ASCOBench ties 288 questions to specific versions of ASCO breast and prostate cancer guidelines, with oncologist-reviewed reference answers; about one in four version-sensitive drafts needed revision or rewriting, against fewer than one in ten factual ones. Only 1 of 14 superseded guideline documents states that it has been replaced, and for the strong model Gemini retrieval over several guideline versions made stale answers about four times as frequent as answering without retrieval, while the verification-first SentryLine lowered incorrect answers to 4.2-5.2%.