Is it time for one-step nucleic acid amplification (OSNA) in colorectal cancer? A systematic review and meta-analysis

Background Lymph node metastasis (LNM) is prognostic in colorectal cancer (CRC). However, evaluation by routine haematoxylin and eosin histology (HE) limits nodal examination and is subjective. Missed LNMs from tissue allocation bias (TAB) might under-stage disease, leading to under-treatment. One-step nucleic acid amplification (OSNA) for CK19 messenger ribonucleic acid (mRNA), a marker of LNM, analyses the whole node. The aim of the present systematic review and meta-analysis was to assess recent studies on OSNA versus HE and its implications for CRC staging and treatment. Methods Databases including OVID, Medline and Google Scholar were searched for OSNA, LNM and CRC. Study results were pooled using a random-effects model. Summary receiver operator curves (SROC) assessed OSNA’s performance in detecting LNM when compared to routine HE histology. Results Five case–control studies analysing 4080 nodes from 622 patients were included. The summary estimates of pooled results for OSNA were sensitivity 0.90 [95% confidence interval (CI) 0.86–0.93], specificity 0.94 (95% CI 0.93–0.95) and diagnostic odds ratio 179.5 (CI 58.35–552.2, p