Introduction

Although circulating tumor DNA (ctDNA) has shown promising results in monitoring response/relapse in pancreatic cancer patients, the limited availability of sensitive, cost-effective, and efficient molecular technologies for their detection has restricted its use. Here, we present a fast single-step methodology utilizing the amplification-refractory mutation system (ARMS) coupled with high-resolution melting analysis (HRMA) as a new method to evaluate KRAS mutations in tumor samples and ctDNA.

Aims & Methods

This is a prospective bicentric cohort study including pancreatic ductal adenocarcinoma cancer patients with tumor samples and liquid biopsies collected at diagnosis. Codon-12 KRAS mutations were tested by Sanger-Sequencing (SS) and G12D, G12V, G12R, G12C mutations were tested by ARMS/HRMA. The frequency of KRAS mutations by both techniques was evaluated. Progression-free survival and overall survival were also calculated.

Results

41 patients, 61% male, with median-age at diagnosis of 69 (IQR 62-76) years-old, 40% with metastatic disease at diagnosis were included. SS detected KRAS mutations in 23 (56%) tumor samples (G12D=12, G12V=7, G12R=2, G12C=2) and ARMS/HRMA in 33 (81%) (G12D=18, G12V=9, G12R=2, G12C=1, G12V/G12D=2, G12D/G12C=1), with a moderate concordance in mutation detection (kappa=0.48, p<0.001). Regarding liquid biopsies, no mutations were detected with SS technique, but ARMS/HRMA detected KRAS mutations in 7 patients (G12D=4, G12V=2, G12V/G12D=1), all of which were in agreement with mutations found in primary tumor. In non-operated patients, those with KRAS mutations detected in liquid biopsies showed a trend towards lower OS compared to patients with wildtype tumors (2 vs 10 months, HR 3.143, p=0.133).

Conclusion

The ARMS/HRMA method is a more effective means of detecting KRAS mutations in both PDAC tumor samples and liquid biopsies compared to SS, although its accuracy in liquid biopsies can be optimized. It might become a cost-effective tool to assess response to medical or surgical therapy as well as to detect early relapse. Further studies are required to validate these findings.

Introduction

Inflammatory Bowel Diseases (IBD) can lead to various complications, with Acute Severe Colitis (ASC) being among the most critical. ASC is a medical and surgical emergency that poses a significant risk to life, necessitating prompt and effective diagnosis and management. The first-line treatment typically involves intravenous corticosteroids. However, some cases are resistant to corticosteroids and require second-line medical therapy or immediate surgical intervention.

Aims & Methods

The objective was to identify factors associated with the failure of first-line medical treatment in patients with ASC. A retrospective descriptive and analytical study was conducted over ten years (January 2014 to March 2024) in the gastroenterology department of Charles Nicolle Hospital. The study included patients with IBD complicated by ASC, defined by the Truelove and Witts criteria and a Lichtiger score greater than 10.Patients with bacterial superinfection were not included.

Results

Forty-five patients over 18 years old were included, with a mean age of 37.87 years (range: 18–74 years). There was a slight female predominance (53%), with a male-to-female ratio of 0.87. In 31% of cases, ASC was the initial presentation of the disease. Endoscopic signs of severity at admission were observed in 49% of patients. All patients received intravenous corticosteroid therapy with hydrocortisone hemisuccinate as the first-line treatment. The response rate to first-line treatment was 64.5%. Second-line medical therapy was administered to 24.4% of patients, consisting of cyclosporine in 11.1% and infliximab in 13.3%. Five patients (11.1%) underwent subtotal colectomy due to corticosteroid failure.
In univariate analysis, factors associated with corticosteroid failure included male gender (p=0.011), absence of extraintestinal manifestations (p=0.017), higher average number of stools on the first day (p=0.013), Lichtiger score >10 on the third (p=0.011) and fifth day (p<0.001), hemoglobin levels >11 g/dL on the first day (p<0.001), >10 g/dL on the third day (p=0.009), >9 g/dL on the seventh day (p=0.013), white blood cell count >10,000/mm³ on the first day (p=0.008), >12,000/mm³ on the third (p=0.001) and seventh day (p=0.004), C-reactive protein (CRP) level >30 mg/L on the seventh day (p=0.005), and persistent endoscopic signs of severity after three to five days of corticosteroid therapy (p=0.001).
Multivariate Analysis showed that only the presence of severe endoscopic signs on follow-up endoscopy after three to five days of corticosteroid therapy was predictive of corticosteroid failure (Odds Ratio = 42.2; p=0.028).

Conclusion

Acute Severe Colitis is a potentially life-threatening complication. The presence of severe endoscopic signs after five days of corticosteroid therapy should prompt the initiation of second-line therapy. Understanding the predictive factors for corticosteroid failure is essential for individualized management to improve both immediate and long-term outcomes.

Disclosure

The authors declare no conflicts of interest.

Introduction

Type 1 AIP is the most common presentation of IgG4-related disease. Serum IgG4 levels are widely used in initial screening and diagnosis, with levels ≥135 mg/dL recommended as part of the diagnostic criteria. However, its diagnostic specificity is limited as it can be elevated in a broad spectrum of neoplastic, infectious, and autoimmune diseases. Histological diagnosis though definitive, remains challenging in real life clinical practice. In recent years, IgG4/IgG ratio has been proposed as a promising alternative serum biomarker.

Aims & Methods

We aimed to study the diagnostic utility of serum IgG4/IgG ratio compared to serum IgG4 alone in the diagnosis of Type 1 AIP. We identified a cohort of patients from 2015 to 2021 who had raised serum IgG4 levels in Tan Tock Seng Hospital, Singapore. Associations between serum IgG4 level and IgG4/IgG ratio were compared to confirmed AIP diagnosis and characteristic computed tomography (CT) and magnetic resonance imaging (MRI) features (diffuse pancreatic swelling, rim-like enhancement). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated at IgG4/IgG thresholds of ≥15% and ≥20%.

Results

Our sample included a total of 60 patients with raised serum IgG4 levels. 21 patients had been diagnosed with Type 1 AIP, and 39 patients had not.
The majority of our patients had serum IgG4 ≥135 mg/dL (n=53, 88.3%). However, there was no significant association between the conventional serum IgG4 cut off of ≥135 mg/dL and the diagnosis of AIP (p = 0.687). In contrast, serum IgG4/IgG ratio demonstrated significantly higher values in patients with AIP compared to those without (median 23.2% vs 13.9%; p < 0.001). Analysis by logistic regression of IgG4/IgG ratio showed an acceptable performance with an area under the curve of 0.779, sensitivity of 92.3%, and specificity of 52.4%.

Variable	Type 1 AIP Present (n=21)	Type 1 AIP Absent (n=39)	Test Statistic	p-value
IgG4/IgG ratio	23.2 (24.0 ± 14.2)	13.9 (13.4 ± 4.5)	U = 184	<0.001
Serum IgG4 ≥135 mg/dL	18/21 (85.7%)	35/39 (89.7%)	Fisher's exact	0.687

We performed further analysis to determine a threshold for diagnostic utility of serum IgG4/IgG ratio. A ratio of ≥20% was strongly associated with AIP diagnosis (OR = 13.2, 95% CI: 3.08–56.5; p < 0.001), with high specificity (92.3%) and PPV (78.6%). Reducing the diagnostic threshold to ≥15% increased sensitivity to 76.2% (vs 52.4% at ≥20%) and improved NPV 84.4%, however this reduced specificity to 69.2%.

Subset analysis was performed among patients with Type 1 AIP (n=21) to evaluate for relationship between serum biomarkers and typical imaging findings (diffuse pancreatic swelling, rim-like enhancement). When stratified to a cut off of ≥135 mg/dL, the association between serum IgG4 levels with imaging findings trended towards positivity, but was not statistically significant (OR 3.14, p = 0.0553, φ 0.196). The IgG4/IgG ratio demonstrated a stronger association with typical imaging findings, although still not achieving statistical significance (OR = 1.065, p = 0.129). This subset analysis is likely limited by the small sample size.

Conclusion

This study demonstrates that serum IgG4/IgG ratio is a superior serological marker compared to serum IgG4 alone, particularly in the diagnosis of type 1 AIP. A threshold ratio of ≥20% demonstrated strong association with AIP diagnosis, with high specificity and PPV.
Our findings support the incorporation of IgG4/IgG ratio - particularly at a cut-off of 20% - as a valuable adjunct in diagnosis of suspected type 1 AIP, and we recommend further research in a larger cohort to validate this data.

References

1. Wallace ZS, Naden RP, Chari S, Choi HK, Della-Torre E, Dicaire JF, et al. The 2019 American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-related disease. Arthritis Rheumatol. 2020;72(1):7–19.
2. Umehara H, Okazaki K, Kawa S, Takahashi H, Yoshino T, Matsui S, et al. The 2020 revised comprehensive diagnostic (RCD) criteria for IgG4-related disease. Mod Rheumatol. 2021;31(3):529–33.
3. Lanzillotta M, Mancuso G, Della-Torre E. Advances in the diagnosis and management of IgG4-related disease. BMJ. 2020;369:m1067.
4. Uchida K, Okazaki K. Current status of type 1 (IgG4-related) autoimmune pancreatitis. J Gastroenterol. 2022;57(10):695–708.
5. Xia CS, Zhang S, Duan L, Zhao CW, Zhang F. Diagnostic performances of serum IgG4 concentration and IgG4/IgG ratio in IgG4-related disease. Clin Rheumatol. 2017;36(11):2769–74.

Introduction

Self-expandable metallic stents (SEMS) are commonly used to relive malignant gastric outlet obstruction (GOO). However, SEMS with high radial force can occurs tissue proliferation caused by mechanical injury. To overcome these problems, drug-eluting stents using antiproliferative drugs have been developed. Specially, everolimus have demonstrated efficacy in reducing restenosis rates in arteries, but their potential application in the gastrointestinal tract remains unexplored. Additionally, recent studies have reported that stents with thinner struts have a reduced risk of clinical restenosis compared to stents with thicker struts. However, the application of everolimus-coated laser-cut stents, which offer robust antiproliferative properties, has not yet been investigated or established in the gastrointestinal tract.

Aims & Methods

This study aims to investigate the efficacy and safety of everolimus-coated laser-cut SEMS in suppressing stent-induced tissue hyperplasia in a rat gastric outlet model.
Everolimus-coated laser-cut SEMS were prepared using ultrasonic spray technology, and the characteristics of the SEMS before and after coating process were evaluated. Twelve male rats were randomly divided into two groups: control (laser-cut SEMS, n = 6) and everolimus (everolimus-coated laser-cut SEMS, n = 6). The effectiveness of everolimus-coated laser-cut SEMS were assessed by comparing results of fluoroscopy, endoscopy, and histopathological analyses.

Results

Everolimus were uniformly coated onto the surface of the laser-cut SEMS and approximately 80% of everolimus was slowly released for a week. Stent placement was successful in all rats. Stent-induced tissue hyperplasia variables were significantly lower in the everolimus group compared to the control group (all p < 0.05). The luminal diameter was significantly larger in the everolimus group than in the control group (p < 0.05). The degrees of α-SMA-, Ki-67-, and BrdU-positive deposition were significantly lower in the everolimus group (p < 0.001), while the degree of TUNEL-positive deposition was significantly higher than in the control group (p < 0.001).

Conclusion

Everolimus-coated laser-cut SEMS effectively suppressed stent-induced tissue hyperplasia in a rat gastric outlet model. Local treatment with everolimu via laser-cut SEMS was safe and effective to maintain the stent patency and has therapeutic potential in the prevention of restenosis after stent placement in the gastrointestinal tract.

Disclosure

No disclosure