IMPACT OF EUS-FNB FROM PERITONEAL LESIONS FOR AVOIDING DIAGNOSTIC LAPAROSCOPY: A PROSPECTIVE COHORT STUDY (THE IMPALA STUDY)

Aims:

To prospectively study impact and amount of tissue for immunohistochemical staining (IHCS) of EUS-FNB from peritoneal lesions.

Methods:

From March 2017 to June 2018, a total of 36 EUS-FNB passes were prospectively performed in 15 patients with peritoneal lesions (7 males, 8 females; mean age 60.9 ± 11.3 years) at the King Chulalongkorn Memorial Hospital, Bangkok, Thailand.

Results:

Ascites was detected by CT and EUS in 87.7% (13/15) and 93.3% (14/15) of patients, respectively. Percutaneous abdominal paracentesis was feasible in 80% (12/15) of patients. Ascites cytology was positive for malignancy in only 6.7% (n = 1) of patients. Median number of passages of EUS-FNB was 3 (2 – 3) times per case. Needle types were 20G needle. No procedure related adverse events. Amount of tissue was graded as grade A (sufficient core tissue for diagnosis and IHCS), B (a diagnosis based on cell morphology), and C (not enough tissue for diagnosis) in 72.2% (26/36), 11.1% (4/36), and 16.7% (n = 6/36) of 36 passes, respectively. Blood contamination was < 25%, 25 – 50% and > 50% in 88.9% (32/36), 5.6% (2/36), and 5.6% (2/36), respectively. Of 13 patients with amount of tissue was graded as A, 9 from 13 showed positive results for malignancy. Diagnoses by IHCS were confirmed by subsequent surgery in 33.3% (3/9) of patients. Benign diagnosis was finally made with long term follow up in 1 from 15 patients. Malignancy was correctly diagnosed by core tissue biopsy from EUS-FNB in 9 from 14 patients (64.3%). For another 5 patients with malignancy, diagnoses were finally made by tissue (n = 3) and follow up (n = 2).

Conclusions:

EUS-FNB from peritoneal lesions provided adequate tissue for IHS in majority of patients and diagnostic laparoscopy is not required in positive cases.