Previous studies which specifically investigated the impact of stent presence on staging
| Authors | Year | EUS type | Cancer location | Stent, n (type) | Comments |
| Cannon et al,29 N=50 | 1998 | Radial | Ampulla | 25 (PS) | Overall accuracy 78%. T staging reduced from 84% to 72% by stent. All patients underwent surgery. |
| Fusaroli et al,14 N=65 | 2006 | Radial | Head of pancreas | 19 (PS) | T stage correct in 85% unstented and 47% with stents. Patients with stents 6.55 times more likely to be incorrectly T staged. All patients underwent surgery. |
| Bao et al,13 N=76 | 2007 | Linear | Head of pancreas | 36 (not stated) | Overall sensitivity 57%, specificity 67%, PPV 61% and NPV 63% for EUS assessment of venous involvement in determining positive resection margin or locally advanced and unresectable at surgery. In 27 patients without stent, were 79%, 69%, 73% and 75% respectively. |
| Shami et al,15 N=55 | 2008 | Linear | Pancreas | 28 (SEMS) | Overall staging not just T or vascular stage assessed. EUS correctly staged 52% of patients without SEMS compared with 46% of patients with SEMS. Surgical exploration in 65% and resection in 25% of patients. Main reason for inaccurate staging was failure to identify metastatic disease. |
EUS, endoscopic ultrasound; NPV, negative predictive value; PPV, positive predictive value; PS, plastic stent; SEMS, self-expandable metal stents.