Patients’ backgrounds
We analyzed 191 patients who underwent their first EUS-FNA/B with the PC20, PC22, or AC22 from April 2013 to October 2019 at Kyorin University Hospital and were eventually diagnosed with pancreatic cancer. In Japan, the PC20, PC22, and AC22 were approved for EUS-FNA/B for pancreatic solid lesions by the Ministry of Health, Labour and Welfare in December 2015, March 2012, and October 2016, respectively. Among the 191 patients, the first EUS-FNA/B was performed in 53 patients from April 2013 to November 2015, in 13 patients from December 2015 to September 2016, and in 125 patients from October 2016 to October 2019. The PC20, PC22, and AC22 were used for 111, 68, and 12 patients, respectively. The patients’ characteristics are shown in Table 1. There was no significant difference in sex, age, tumor location, or puncture route among the needles. However, the maximum diameter of the tumor measured on contrast-enhanced computed tomography images was significantly different among the needles (PC20, 37.9±1.2 mm; PC22, 32.9±1.2 mm; AC22, 22.7±2.6 mm; p<0.0001). Although a sufficient stroke length of puncture was secured in all patients, the maximum stroke length for puncture measured on EUS images was shorter with the AC22 (22.1±2.2 mm) (p<0.01 and p<0.01 compared with PC20 and PC22, respectively), while there was no significant difference between the PC20 and PC22 (30.6±0.7 and 30.3±0.8 mm, respectively; p>0.99). The number of passes was significantly higher with the PC22 (4.1±0.7) than PC20 (3.7±0.9, p<0.01) and AC22 (3.5±0.6, p<0.05).
Diagnostic accuracy of EUS-FNA/B needles for pancreatic cancer
The diagnostic accuracy for pancreatic cancer with the PC20 was 96.4% (107/111), 81.1% (90/111), and 96.4% (107/111) by histology, cytology, and the combination of histology and cytology, respectively (Table 2). The accuracy with the PC22 was 58.8% (40/68), 63.2% (43/68), and 72.1% (49/68) and that with the AC22 was 75.0% (9/12), 83.3% (10/12), and 91.7% (11/12), respectively (Table 2). The diagnostic accuracy with the PC20 by histology, cytology, and the combination of histology and cytology was significantly better than that with the PC22 (p-adj<0.0001, p-adj<0.05, and p-adj<0.0001, respectively), while there was no significant difference between the PC20 and AC22 (p-adj=0.06, p-adj>0.99, and p-adj>0.99, respectively). The addition of cytological assessment to histological assessment improved the diagnostic accuracy with the PC22 and AC22 but not with the PC20. Comparison of diagnostic accuracy between two needles (PC20 vs. PC22, PC20 vs. AC22 and PC22 vs. AC22) are shown in Supplementary Table 1. Meanwhile, the diagnostic accuracy in each pancreatic location tended to be better in PC20 and AC22 compared to PC22 (Supplementary Table 2). Next, we examined the diagnostic efficacy of the first pass. The histological accuracy in the first pass was 85.6 (95/111) with the PC20, 33.8% (23/68) with the PC22, and 66.7% (8/12) with the AC22 (Table 3). The accuracy was significantly higher with the PC20 than PC22 (p-adj<0.0001), while there was no significant difference between the PC20 and AC22 (p-adj=0.32). The proportion of adequate specimens by MOSE among the samples from the first pass was 63.9% (71/111) with the PC20, 41.2% (28/68) with the PC22, and 50.0% (6/12) with the AC22. There was no significant difference among the needles (p=0.20) (Table 3, Supplementary Table 3). The histological accuracy among adequate specimens and clotted specimens was 81.7% and 92.5% with the PC20, 39.3% and 30.0% with the PC22, and 83.3% and 50.0% with the AC22.
Requirement of additional EUS-FNA/B needles
Among the 111 cases in which the PC20 was used, 5 (4.5%) required a biopsy needle change. The needle was distorted and the stylet could not be inserted in two of these five cases. In the other three cases, the needles were changed because of insufficient specimens (i.e., fragment specimens by MOSE). The PC22 was changed in 7 cases because of fragment specimens (10.3%, 7/68). Two cases in which the AC22 was used required a needle change because of fragment specimens (16.7%, 2/12). There was no significant difference in the requirement of a needle change among the different needle types (p=0.20) (Table 4).
Adverse events related to EUS-FNA/B procedure
One patient in the PC20 group developed mild pancreatitis (0.9%, 1/111). The patient recovered with conservative treatment (fasting, fluid replacement, protease inhibitor, and antibiotic therapy). No adverse events occurred among the patients in the PC22 group (0.0%, 0/68) or AC22 group (0.0%, 0/12) (p=0.54).