“Sequential Sampling” Strategy Optimises the Use of Two Endoscopic Ultrasound (EUS)-Guided Tissue Sampling Techniques

Abstract

Background: Each of the two EUS-guided sampling techniques; fine needle aspiration (FNA) and Trucut biopsy have advantages and limitations when used alone. We have previously shown that combining the two techniques increases the accuracy of sampling when carried out without a cytopathologist on-site, but, performing both FNA and Trucut biopsies in every patient may not be cost effective. Aim: To compare the efficacy of a strategy of “sequential sampling” (performing FNA only when Trucut biopsy samples were inadequate) with that of ‘dual sampling’ (performing both FNA and Trucut biopsy) in patients undergoing EUS-guided tissue sampling. Methods: All lesions that could be approached via transoesophageal and transgastric approach were considered suitable for Trucut biopsy. The lesions that needed a transduodenal approach were included only when a straight scope position could be achieved. Only those with lesions where EUS Trucut biopsy was deemed feasible were included in the analysis. ‘Sequential sampling’ involved maximum 4 passes with the Trucut needle followed by FNA only when samples obtained by Trucut were considered inadequate by the endosonographer. “Dual sampling” was performed using a predetermined protocol. Data collected prospectively from 36 patients (21 male) aged 15-86 (median 62) years who underwent “dual sampling” were compared with those from 41 patients (33 male) aged 34-83 (median 66) years who had “sequential sampling”. Results: Mean diameter of the targeted lesions was significantly lower in the “sequential sampling” group (2.54 ± 1.4 vs 3.56 ± 1.5 cm; p < 0.005). Majority of EUS-guided samplings were performed via transoesophageal or transgastric route in both groups (37/41 vs 29/36; p = 0.3). Significantly fewer number of needle passes were made with the “sequential sampling” strategy compared with that of “dual sampling” (mean 3.56 ± 1.5 vs 6.05 ± 1.2; p < 0.0001). In the “sequential sampling” group 8/41 (20%) needed both EUS-FNA and Trucut biopsies. The diagnosis reached with “sequential sampling” was accurate in 37/41 (90%) cases compared with 33/36 (92%) with “dual sampling” (p = 1.0). Conclusions: “Sequential sampling” is an effective strategy in cases where Trucut biopsy. is technically feasible and yields an accurate diagnosis in 90% of cases. High degree of accuracy of diagnosis was maintained even when the target lesions were smaller. This strategy will lead to 20% of the patients undergoing both FNA and Trucut biopsies. Background: Each of the two EUS-guided sampling techniques; fine needle aspiration (FNA) and Trucut biopsy have advantages and limitations when used alone. We have previously shown that combining the two techniques increases the accuracy of sampling when carried out without a cytopathologist on-site, but, performing both FNA and Trucut biopsies in every patient may not be cost effective. Aim: To compare the efficacy of a strategy of “sequential sampling” (performing FNA only when Trucut biopsy samples were inadequate) with that of ‘dual sampling’ (performing both FNA and Trucut biopsy) in patients undergoing EUS-guided tissue sampling. Methods: All lesions that could be approached via transoesophageal and transgastric approach were considered suitable for Trucut biopsy. The lesions that needed a transduodenal approach were included only when a straight scope position could be achieved. Only those with lesions where EUS Trucut biopsy was deemed feasible were included in the analysis. ‘Sequential sampling’ involved maximum 4 passes with the Trucut needle followed by FNA only when samples obtained by Trucut were considered inadequate by the endosonographer. “Dual sampling” was performed using a predetermined protocol. Data collected prospectively from 36 patients (21 male) aged 15-86 (median 62) years who underwent “dual sampling” were compared with those from 41 patients (33 male) aged 34-83 (median 66) years who had “sequential sampling”. Results: Mean diameter of the targeted lesions was significantly lower in the “sequential sampling” group (2.54 ± 1.4 vs 3.56 ± 1.5 cm; p < 0.005). Majority of EUS-guided samplings were performed via transoesophageal or transgastric route in both groups (37/41 vs 29/36; p = 0.3). Significantly fewer number of needle passes were made with the “sequential sampling” strategy compared with that of “dual sampling” (mean 3.56 ± 1.5 vs 6.05 ± 1.2; p < 0.0001). In the “sequential sampling” group 8/41 (20%) needed both EUS-FNA and Trucut biopsies. The diagnosis reached with “sequential sampling” was accurate in 37/41 (90%) cases compared with 33/36 (92%) with “dual sampling” (p = 1.0). Conclusions: “Sequential sampling” is an effective strategy in cases where Trucut biopsy. is technically feasible and yields an accurate diagnosis in 90% of cases. High degree of accuracy of diagnosis was maintained even when the target lesions were smaller. This strategy will lead to 20% of the patients undergoing both FNA and Trucut biopsies.