Computed tomography overestimation of esophageal tumor length: Implications for radiotherapy planning

AIM:To assess the relationship between preoperative computed tomography(CT)and postoperative pathological measurements of esophageal tumor length and the prognostic significance of CT tumor length data.METHODS:A retrospective study was carried out in 56 patients who underwent curative esophagogastrectomy.Tumor lengths were measured on the immediate preoperative CT and on the post-operative resection specimens.Inter-and intra-observer variations in CT measurements were assessed.Survival data were collected.RESULTS:There was a weak correlation between CT and pathological tumor length(r=0.30,P=0.025).CT lengths were longer than pathological lengths in 68%(38/56)of patients with a mean difference of 1.67 cm(95%CI:1.18-2.97).The mean difference in measurements by two radiologists was 0.39 cm(95% CI:-0.59-1.44).The mean difference between repeat CT measured tumor length(intra-observer variation) were 0.04 cm(95%CI:-0.59-0.66)and 0.47 cm (95%CI:-0.53-1.47).When stratified,patients not receiving neoadjuvant chemotherapy showed a strong correlation between CT and pathological tumor length(r =0.69,P=0.0014,n=37)than patients that did(r= 0.13,P=0.43,n=19).Median survival with CT tumor length>5.6 cm was poorer than with smaller tumors,but the difference was not statistically significant.CONCLUSION:Esophageal tumor length assessed using CT does not reflect pathological tumor extent and should not be the only modality used for management decisions,particularly for planning radiotherapy.