Immune checkpoint blockade has recently been reported to be effective in treating microsatellite instability (MSI)-high tumors. Therefore, sufficient sampling of histological specimens is necessary in cases of unresectable pancreatic cancer (UR-PC). This multicenter study investigated the efficacy of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) using a Franseen needle for MSI evaluation in patients with UR-PC.
A total of 89 patients with UR-PC who underwent endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) or EUS-FNB using 22-G needles at three hospitals in Japan (2018–2021) were enrolled. Fifty-six of these patients (FNB 23 and FNA 33) were followed up or evaluated for MSI. Patient characteristics, UR-PC data, and procedural outcomes were compared between patients who underwent EUS-FNB and those who underwent EUS-FNA.
No significant difference in terms of sufficient tissue acquisition for histology was observed between patients who underwent EUS-FNB and those who underwent EUS-FNA. MSI evaluation was possible significantly more with tissue samples obtained using EUS-FNB than with tissue samples obtained using EUS-FNA (82.6% [19/23] vs. 45.5% [15/33], respectively;
EUS-FNB using a Franseen needle is desirable for ensuring sufficient tissue acquisition for MSI evaluation.
Pancreatic cancer (PC) is a lethal disease and a major cause of cancer-related deaths worldwide.
Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is an efficient and a safe method for sampling PC specimens.
A total of 89 UR-PC patients who underwent EUS-FNA or EUS-FNB (EUS-FNAB) using 22-G needles between December 2018 and December 2021 at three hospitals in Japan (Fukushima Medical University Hospital, Aizu Medical Center of Fukushima Medical University, and Ohtanishinouchi Hospital) were enrolled (
All institutions that participated in this study were affiliated hospitals at the Fukushima Medical University. Therefore, the procedural and histological diagnostic criteria were almost identical. In addition, histological specimens obtained from the Ohtanishinouchi Hospital were sent for analysis to the Department of Diagnostic Pathology, Fukushima Medical University, through highly secure internet communication.
After the patients were sufficiently sedated with intravenous administration of midazolam and placed in the left lateral decubitus position, we gently inserted an echoendoscope. When the lesion was observed on the monitor, the lack of blood flow on the puncture line was confirmed using doppler mode. The lesion was punctured and the stylet was removed. The needle was passed back and forth 20 times in the lesion while suction was applied using a 10-mL or 20-mL syringe. White lumbricoid specimens were separated from all the specimens collected using EUS-FNAB. The lumbricoid specimens were preserved in a bottle filled with formalin for subsequent histological diagnosis. The remaining specimens were used for cytology and rapid onsite evaluation (ROSE).
The following echoendoscopes and ultrasonography equipment were used: GF-UC240AL-5, GF-UCT260, EU-ME-1, and EU-ME-2 (Olympus Medical Systems, Tokyo, Japan). The needles were selected as follows. For patients with vessels near the puncture line, a conventional FNA needle was used because of its good penetration ability. Otherwise, the endoscopist randomly selected the needle. The Franseen Acquire 22-G needle (Boston Scientific, Marlborough, MA, USA) was used for EUS-FNB (
All procedures were performed by pancreaticobiliary specialists who had performed more than 200 EUS-FNAB procedures or by beginners under the guidance of pancreaticobiliary specialists.
Patient characteristics (age, sex), UR-PC data (tumor size, location, and progression), and procedural outcomes (puncture route, puncture number, possibility of histological diagnosis, possibility of performing MSI evaluation, and adverse events) were compared between patients who underwent EUS-FNB and those who underwent EUS-FNA. Additionally, a multivariate analysis was performed to determine the factors that influenced the possibility of MSI evaluation. Tumor size was measured using computed tomography or EUS. Locally advanced UR-PC was determined under the following conditions: (1) invades/contacts the portal vein or superior mesenteric vein by >180° with a range of invasion/contact transcending the inferior duodenal angle; (2) invades/contacts the celiac artery or superior mesenteric artery by >180°; (3) invades/contacts the common hepatic artery with a range of invasion/contact extending to the celiac artery or proper hepatic artery; and (4) invades/contacts the aorta.
MSI evaluations for the three hospitals were performed by an external agency (Falco Holdings Co., Kyoto, Japan). If a histological specimen did not satisfy the conditions required for MSI evaluation, the specimen was not submitted to the outside agency for pathological judgment.
Histological diagnosis was made using all specimens submitted to the department of pathology. A formalin-fixed paraffin-embedded (FFPE) block was designated for each procedure performed at the Fukushima Medical University and Aizu Medical Center. Alternatively, an FFPE block was prepared for each puncture at the Ohtanishinouchi Hospital. To diagnose whether a tumor is malignant, the specimen must include tumor tissue that has not degenerated or crushed. Furthermore, when a specimen contains inflammatory contents, it becomes difficult to identify whether atypical cells are tumoral or reactive to inflammation.
The conditions for histological specimens required by the outside agency (Falco Holdings Co.) were as follows: more than 2,000 PC cells to extract DNA for MSI evaluation, PC cell content >50%, and more than five unstained PC slide specimens must be prepared. An MSI detection kit, called the Promega panel, was used to analyze MSI using five mononucleotide markers (BAT-25, BAT-26, NR-21, NR-24, and MONO-27). Although the Bethesda panel has been used for MSI evaluation for a long time,
The Mann-Whitney
This multicenter retrospective study was approved by the Institutional Review Board of Fukushima Medical University (IRB No: 2021-002). Patients were not required to provide informed consent because this study used anonymous clinical data obtained after each patient had agreed to medical activities by written consent. For full disclosure, the details of this study are published on the homepage of the Fukushima Medical University.
Patient characteristics, tumor size, PC location, and PC progression were not significantly different between patients who underwent FNB and those who underwent FNA (
Three needles were used in the patients who underwent EUS-FNA. However, Expect was used in most patients who underwent EUS-FNA. When patient characteristics and outcomes were compared between EUS-FNB and FNA using Expect, the results were similar to those of the comparison between EUS-FNB and FNA in all patients (
In the univariate analysis, EUS-FNB was a significant factor influencing the possibility of MSI evaluation. The current guideline recommends three to four needle passes with FNA needles or two to three needle passes with FNB needles.
We investigated the efficacy of EUS-FNB with a Franseen needle for MSI evaluation. No significant difference in terms of sufficient tissue acquisition for histology was observed between patients who underwent EUS-FNB and those who underwent EUS-FNA. MSI evaluation can be performed more often with samples obtained using EUS-FNB than with those obtained using EUS-FNA.
MSI-high PC is rare. In previous reports with large sample sizes, MSI-high PC was detected in 0.5%–2% of patients.
In this study, sufficient tissue acquisition for histology was achieved using EUS-FNA. However, in previous reports, more tissue was obtained with EUS-FNB than with EUS-FNA.
This study has several limitations. First, it was an observational study with a small number of patients. However, according to the results of this study, the possibility of MSI evaluation was 82.6% and 45.5% in the FNB and FNA groups, respectively. A total of 52 patients were required to achieve an α error of 5% and a β value of 0.2. When the main outcome was the possibility of MSI evaluation, a minimum sample size was maintained. Second, the EUS-FNAB needles were not randomly assigned. Third, the handling of histological specimens differed across institutions. Because an FFPE block was made for each puncture at the Ohtanishinouchi Hospital, the number of tumor cells on the glass slide decreased, making it difficult to perform MSI evaluation. In the future, a multicenter prospective study should be conducted to verify the results of this study. Fourth, the volume of the UR-PC specimen was not numerically measured. Instead, the suitability of MSI evaluation was compared between patients who underwent EUS-FNA and those who underwent EUS-FNB using a Franseen needle. The histological diagnoses and possibility of MSI evaluation were evaluated by pathologists with considerable experience.
In conclusion, obtaining sufficient tissue samples for histological analysis is possible with EUS-FNA, similar to EUS-FNB. However, EUS-FNB using a Franseen needle is desirable for obtaining sufficient tissue samples for MSI evaluation and could aid in clinical decision-making regarding the treatment of patients with UR-PC.
The authors have no potential conflicts of interest.
None.
We thank all the staff at the Department of Gastroenterology of Fukushima Medical University (Ohtanishinouchi Hospital and Aizu Medical Center), the Department of Endoscopy of Fukushima Medical University Hospital, and the gastroenterology ward of the Fukushima Medical University Hospital.
Conceptualization: TT, MS, HO; Data curation: TT, MS, HI, YT, YN; Formal analysis: TT, MS; Investigation: TT, MS, YH; Methodology: TT, MS; Project administration: TT, MS; Supervision: YH, GS, SM, TH, HO, RS, NK, HA, YS, HI, JN, MT, MH, TK, RK; Writing–original draft: TT, MS; Writing–review & editing: all authors.
Flowchart of the patient groups in this study. EUS-FNAB, endoscopic ultrasound-guided fine-needle aspiration or biopsy; UR-PC, unresectable pancreatic cancer; FNB, fine-needle biopsy; FNA, fine-needle aspiration; MSI, microsatellite instability.
The Franseen needle used for endoscopic ultrasound-guided fine-needle biopsy. The cutting surface of the conventional fine-needle aspiration needle has a lancet shape. The area of the cutting surface becomes larger by adopting the Franseen design.
Comparison of UR-PC patient characteristics
Variable | FNB ( |
FNA ( |
|
---|---|---|---|
Age (yr) | 67 (45–78) | 70 (38–82) | 0.08 |
Sex (male:female) | 17:6 | 23:10 | 0.77 |
Size of tumor (mm) | 30 (15–58) | 30 (15–82) | 0.84 |
PC location (head:body or tail) | 8:15 | 18:15 | 0.18 |
PC progression (LA:M) | 7:16 | 8:25 | 0.76 |
Values are presented as median (range) unless otherwise indicated.
UR, unresectable; PC, pancreatic cancer; FNB, fine-needle biopsy; FNA, fine-needle aspiration; LA, locally advanced; M, metastatic.
Comparison of outcomes of EUS-FNAB in the UR-PC patients
Variable | FNB ( |
FNA ( |
|
---|---|---|---|
Puncture route (gastric:duodenal:gastric and duodenal) | 15:7:1 | 20:13:0 | 0.47 |
Needle | |||
Acquire | 23 | 0 | |
Expect | 0 | 20 | |
EZ Shot 3 Plus | 0 | 9 | |
Echotip | 0 | 4 | |
Puncture | 2 (2–6) | 3 (1–7) | 0.27 |
Possibility of histological diagnosis | 21 (91.3) | 24 (72.7) | 0.10 |
Possibility of MSI evaluation | 19 (82.6) | 15 (45.5) | <0.01 |
MSI-high tumor | 0 | 1 | |
Adverse event | 0 | 1 | 1.0 |
Bleeding | 0 | 1 |
Values are presented as median (range) or number (%) unless otherwise indicated.
EUS-FNAB, endoscopic ultrasound-guided fine-needle aspiration and biopsy; UR, unresectable; PC, pancreatic cancer; FNB, fine-needle biopsy; FNA, fine-needle aspiration; MSI, microsatellite instability.
Comparison of EUS-FNB and FNA using Expect needles
Variable | FNB ( |
FNA using Expect ( |
|
---|---|---|---|
Age (yr) | 67 (45–78) | 69.5 (38–80) | 0.24 |
Sex (male:female) | 17:6 | 7:13 | 0.74 |
Size of tumor (mm) | 30 (15–58) | 32.5 (15–82) | 0.65 |
PC location (head:body or tail) | 8:15 | 11:9 | 0.23 |
PC progression (LA:M) | 7:16 | 5:15 | 0.75 |
Puncture route (gastric:duodenal:gastric and duodenal) | 15:7:1 | 12:8:0 | 0.87 |
Puncture | 2 (2–6) | 3.5 (1–7) | 0.25 |
Possibility of histological diagnosis | 21 (91.3) | 14 (70.0) | 0.12 |
Possibility of MSI evaluation | 19 (82.6) | 8 (40.0) | <0.01 |
MSI-high tumor | 0 | 1 | |
Adverse event | 0 | 1 | 0.47 |
Bleeding | 0 | 1 |
Values are presented as median (range) or number (%) unless otherwise indicated.
EUS-FNB, endoscopic ultrasound-guided fine-needle biopsy; FNA, fine-needle aspiration; PC, pancreatic cancer; LA, locally advanced; M, metastatic; MSI, microsatellite instability.
Factors influencing the possibility of MSI evaluation
Variable | Univariate |
Multivariate |
||||
---|---|---|---|---|---|---|
OR | 95% CI | OR | 95% CI | |||
Age (≥68 yr) | 0.34 | 0.11–1.06 | 0.062 | |||
Male sex | 0.62 | 0.18–2.10 | 0.44 | |||
Tumor size (≥30 mm) | 0.72 | 0.24–2.18 | 0.57 | |||
Tumor location (head) | 1.97 | 0.66–5.91 | 0.23 | |||
UR-PC (metastatic) | 0.71 | 0.20–2.44 | 0.58 | |||
EUS-FNB | 5.70 | 1.59–20.4 | <0.01 | 4.92 | 1.34–18.1 | 0.017 |
Puncture rout (duodenal) | 1.50 | 0.49–4.63 | 0.48 | |||
Puncture (≥3) | 0.33 | 0.10–1.10 | 0.072 | 0.44 | 0.12–1.58 | 0.21 |
MSI, microsatellite instability; OR, odds ratio; CI, confidence interval; UR-PC, unresectable pancreatic cancer; EUS-FNB, endoscopic ultrasound-guided fine-needle biopsy.