THE ROLE OF RECTAL EUS-FNA/B IN PRE-SACRAL UNDEFINED LESIONS IN PATIENTS WITH HISTORY OF LOWER GI NEOPLASIA

Aims Colo-rectal neoplasia is one of the most commonly diagnosed malignancies. Pre-sacral lesions may arise in the follow up after colo-rectal surgery, after adjuvant chemotherapy (CT), or neo-adjuvant chemo-radiotherapy. CT scan and pelvic RM are the two most used diagnostic tool in these patients, but they can be inconclusive in the diagnosis of pre-sacral lesions. PET scan adds more information but, in presence of inflammation, can show false positive results.To evaluate the role and the efficacy of endoscopy ultrasound (EUS) and Fine Needle Aspiration or Biopsy (FNA/FNB) in the multimodal restaging of suspected local recurrence or progression disease in patients with history of rectal cancer. The number of EUS FNA/FNB passes was based on the gross morphology of the specimen.

Methods From September 2015 to August 2019 we retrospective enrolled eight patients undergoing endoscopy ultrasound (EUS) and Fine Needle Aspiration or Biopsy (FNA/FNB) for pre-sacral lesions. In all cases the radiological findings (CT scan and or PET/MRI) were inconclusive for a final diagnosis.

Results In 7 of 11 patients pathological evaluation confirmed the suspicion of local recurrence and they were referred for oncological re-treatment. In four patients EUS-FNB of lymph-nodes or masses yielded a diagnosis of inflammation or fibrosis. Radiological follow-up for these patients confirmed the benign characteristics. In only two cases both cytology and histology were performed, and in both tissue acquisition by EUS-FNB allowed to reach a diagnosis. In only one of three cases in which lymph-nodes were targeted, cytology evaluation on an EUS-FNB of 15 mm lymph-node showed tumoral cells. Procedures were performed in out-patient setting. All patients underwent antibiotic prophylaxis with intra-venous cephalosporin before FNA/B. No adverse events or infection were observed.

Conclusions In presence of undefined pre-sacral lesions EUS-FNA/B, must be a mandatory diagnostic tool in patients with a history of lower GI neoplasia.