Nodal stage migration and prognosis in anal cancer: a systematic review, meta-regression, and simulation study

摘要: Summary Background In patients with squamous cell carcinoma of the anus (SCCA), lymph node positivity (LNP) indicates poor prognosis for survival and is central to radiotherapy planning. Over past three decades, LNP proportion has increased, mainly reflecting enhanced detection newer imaging modalities; a process known as nodal stage migration. If accompanied by constant T distributions, both node-positive node-negative groups may improve without any increase in overall individual patients; paradox termed Will Rogers phenomenon. Here, we aim systematically evaluate impact migration on SCCA address novel hypothesis that this phenomenon results reduced prognostic discrimination. Methods We did systematic review meta-regression quantify changes over time change searched MEDLINE, Embase, Cochrane Library identify randomised trials observational studies published between Jan 1, 1970, Oct 11, 2016. Studies were eligible if received chemoradiotherapy or main treatment, reported proportions (all studies), (not necessarily present all studies). excluded fewer than 50 patients. extracted study-level data standardised, piloted form. The primary outcome measure was 5-year survival. To investigate scenarios which discrimination might occur, simulated varying true survival, compared these expected observed outcomes levels misclassification state. Findings identified 62 reporting proportions, included 10 569 From these, 45 (6302 patients) whole cohort 11 stratified status, 20 hazard ratios our analyses temporal changes. studies, increased from mean estimate 15·3% (95% CI 10·5–20·1) 1980 37·1% (34·0–41·3) 2012 (p Interpretation describe consequence staging anal cancer have used new observation infer more 30% seen modern clinical series (11 out 15 median year since 2007) are higher proportion. introduction technologies oncology misclassify disease stage, spuriously informing management ultimately increasing risk overtreatment. Funding Bowel Disease Research Foundation.