Controlled Trial Comparing the Performance of 22 Gauge Versus 25 Gauge EUS-FNA Needles (FNA-22G-25G)
Condition: Mediastinal Tumours and Lymph Nodes; Celiac, Perigastric and Peri-pancreatic Lymph Nodes; Pancreatic Masses; Liver Masses; Adrenal Masses
MeSH terms: Mediastinal Neoplasms
Study type: Observational

Summary: 
      The aim of the study is to compare the performance characteristics of EUS-FNA 22 Gauge needle
      and EUS FNA 25 Gauge needle in terms of cellularity and diagnostic yield for diagnosis of
      various pathologies, including lymph nodes, pancreatic, luminal and other lesions outlined by
      EUS.
    

Detailed description: 
      Tissue acquisition by Endoscopic ultrasound plays a central role in diagnosis of several
      pathologies; this is achieved by obtaining cytological material with fine needle aspiration
      (FNA) needles that are able to provide smears of malignant cells. Several needles are at
      present available including 19 Gauge, 22 Gauge and 25 Gauge needles. A 22 Gauge needle is at
      present the standard needle and most of the EUS-FNA results are based on FNA with this
      needle.

      Twenty five Gauge needles presently available on the market are distinctly small, highly
      flexible and may be easier to penetrate hard pancreatic tumors. There even is anecdotal
      messages that this size of needle may be able to traverse relatively large vascular
      structures without major risk. However, there is very scant data on whether a 25 G needle is
      comparable to a standard 22 G needle in terms of specimen cellularity and quality. There is
      only one small randomized trial published as an abstract by Lee et al reporting no
      statistical significant difference in cellularity between the two groups of needle size as
      judged by 2 different cytologists. However, the conclusion is dubious because considerable
      bias may be present since both needles were used in the same lesion. There is therefore a
      need for a properly designed randomized study comparing different needle sizes.

      This study is a prospective randomized multicenter study. Patients referred to one of the
      participating departments for an EUS examination will be included prospectively. Linear EUS
      examination will be done with a linear echoendoscope for lymph nodes, mediastinal, pancreatic
      and other intra-abdominal masses.

      Tumor and lymph node characteristics will be carefully described: size (long axis),
      echogeneity (hypoechoic, hyperechoic, mixed), and echostructure (homogenous, in-homogenous,
      calcifications), shape (round, oval, triangular), border (regular, irregular).

      EUS-guided cell sampling will be performed with a 22 G (Medi-Globe, Sonotip II) and 25 G
      (Medi-Globe, Sonotip II) needles under EUS and Colour-Doppler guidance.

      Needle order will be selected randomly, one single needle pr. Lesion. Three passes will be
      performed with either of the needles after randomization, using 6 uniform to and fro
      movements on every pass with continuous 10cc suction for the reason of standardization. The
      material will be expelled on separate numbered glass slides. The cytopathologist will review
      the material after staining blinded to the needle size and will be using standardized
      criteria for evaluation of cellularity.

      Doubtless, this multicenter randomized controlled trial comparison, as any other experimental
      method, needs with necessity a serious statistical evaluation, bringing the benefits of
      improving the reliability and credibility of the findings thus obtained. Accordingly, both
      exploratory data analysis and statistical inference will be performed. Technically, the
      expected number of lesions to be included in the study will be 220, 110 in each group. Block
      randomization (block size = 4) will be used to ensure exactly equal treatment numbers at
      certain equally spaced points in the sequence of patients assignments (Knuth shuffle
      algorithm for random permutations).

      For diagnostic tests the sensitivity, specificity positive and negative predictive value and
      diagnostic accuracy will be calculated and calculated separately for EUS-FNA during 1st pass,
      2nd pass and 3rd pass by comparing the results with the final diagnosis. All results will be
      expressed as mean, standard deviation (SD) and confidence interval. Testing hypotheses will
      be used afterwards. An a priori power analysis will be performed to determine the appropriate
      sample size in order to achieve adequate power for the statistical tests subsequently used.
      The data from both groups will be compared by standard comparison tests chi-square test or
      Fishers exact test where appropriate. The level of statistical significance is stated as
      0.05.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients referred to one of the participating departments for an EUS examination with
        EUS-FNA (mediastinal tumours and lymph nodes, celiac, perigastric and peri-pancreatic lymph
        nodes, pancreatic masses, liver masses, adrenal masses, etc.).
      
Biospecimen description: 
      Pathology samples obtained through EUS-FNA biopsy processed by paraffin embedding.
    
Keywords: EUS-FNA; 22 Gauge Needle; 25 Gauge Needle