Assessment of standard EUS FNB for molecular testing in cancers; a retrospective tertiary center study

Aims Precision oncology is a promising development in cancer treatment that uses target therapies based on the genomic profile of a patient's cancer. Nearly 30% of pancreatic cancers have detectable genomic lesions that could potentially impact management. This study assessed whether standard endoscopic ultrasound-guided fine needle biopsy (EUS FNB) could produce sufficient samples for molecular research.

Methods Data from electronic medical records was used to perform a retrospective analysis on patients who underwent EUS-guided FNB for solid gastrointestinal lesions at Manchester University NHS Foundation Trust between January 1 and December 31, 2022. Lymphoma samples and cystic lesions were not included. Specimens were deemed adequate if over 100 tumor cells were present and malignant cells constituted over 20% of the sample. Samples were categorized as borderline when tumor cellularity was low or marginal, generally less than 20%. Additionally, extensive necrosis lowered sample quality, even if cellularity surpassed cutoff. Necrosis indicates biomolecule degradation, jeopardizing molecular analyses. Thus borderline samples, despite containing some tumor content, are at risk for failed genomic testing from insufficient or poor quality cells.Our standard protocol involves; three passes of a 22ga EUS FNB Needle (Acquire, Boston Scientific, Natick, MA). Rapid onsite cytologic evaluation (ROSE) was not available.

Results Preliminary results were analysed from 42 cases. 36 samples met our inclusion criteria, while 6 cases were excluded (4 cysts, 1 reactive lymph node and one rectal adenocarcinoma). The mean age of patients was 64.8 years. The mean mass size was 35.3 mm. Of the 36 samples, 23 (63.8%) were deemed suitable for molecular testing while 6 (16.6%) were borderline[JG1] [na2] . The remaining 7 samples (19.4%) were inadequate for molecular testing. For these inadequate samples, there was no statistical difference based on location. There were no adverse events recorded.

Conclusions Preliminary findings from 36 EUS-guided samples for solid GI massesdemonstrate the feasibility of obtaining adequate material for molecular profiling, in 2/3s of cases. However, 19% were still inadequate. Ongoing optimization of tissue acquisition, processing and analysis is vital to further improve molecular diagnostic yield and to allow personalized medicine in pancreatic cancer. The study is limited by sample size. We suggest larger studies are required to identify the ideal technique; for example, in terms of needle used, number of passes and tissue acquisition method. Ultimately, will allow to align strategies, strengthening the implementation of EUS tissue sampling for genomics-driven cancer care. [1] [2]

Publication History

Article published online:
15 April 2024

• References

• 1 Elhanafi S., Mahmud N., Vergara N., Kochman M.L., Das K.K., Ginsberg G.G., Rajala M., Chandrasekhara V.. Comparison of endoscopic ultrasound tissue acquisition methods for genomic analysis of pancreatic cancer. Journal of gastroenterology and hepatology 2019; 34 (05) 907-913
• 2 Karlovich C.A., Williams P.M.. Clinical Applications of Next-Generation Sequencing in Precision Oncology. Cancer journal (Sudbury, Mass.) 2019; 25 (04) 264-271