Clinical Utility of Endoscopic Ultrasound-Guided Fine-Needle Aspiration and Biopsy for Rectal and Perirectal Lesions With Categorization of Their Indications.

Objective: Endoscopic ultrasound-guided fine-needle aspiration and/or biopsy (EUS-FNA/B) is a diagnostic tool for gastrointestinal (GI) lesions. However, its effectiveness in the lower GI tract remains underreported. In this study, we aimed to evaluate the clinical utility of EUS-FNA/B for rectal and perirectal lesions.

Methods: Seventy-seven consecutive patients with rectal or perirectal lesions underwent EUS-FNA/B between 2009 and 2023. The histological diagnoses by EUS-FNA/B were compared with the final diagnoses to assess the former's diagnostic performance. Additionally, the therapeutic utility of EUS-FNA/B and its clinical applicability across various scenarios were investigated.

Results: Twenty-nine of the 77 patients had rectal lesions, with gastrointestinal stromal tumor (GIST) being the most common in 15 patients. Of the 48 patients with perirectal lesions, 27 and 21 had malignant and benign lesions, respectively. EUS-FNA/B was diagnostic in 61 (79.2%) patients, with the rates of 79.3% and 79.2% for rectal and perirectal lesions. EUS-FNA/B enabled timely treatment decisions by confirming malignancy (n = 32) and prevented unnecessary surgeries/procedures by establishing the benign nature of the lesions (n = 14). A definitive diagnosis of rectal GIST was made using EUS-FNA/B, thereby facilitating the initiation of neoadjuvant chemotherapy followed by anus-saving surgery (n = 10). EUS-FNA/B enabled the implementation of minimally invasive interventions such as EUS-guided drainage (n = 5). Adverse events occurred in five (6.5%) patients, with only one requiring hospitalization.

Conclusions: EUS-FNA/B is a valuable modality for patients with rectal or perirectal lesions, which facilitates accurate histological diagnosis, appropriate treatment, and favorable safety profiles.