GS05 - Preoperative Biopsy in the Management of Presacral Tumors: the Mayo Experience

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Purpose/Background: Presacral tumors represent a rare and diverse pathological group. Tissue diagnosis can be critical in determining the utility of neoadjuvant therapy and indeed the required extent of resection, both of which have a significant impact on perioperative morbidity and health-related quality of life. Despite this, the role of preoperative biopsy remains debated in the literature, with advances in high resolution imaging and improved diagnostic accuracy balanced against the theoretical risk of biopsy-related complications. This study aims to compare the diagnostic accuracy of imaging compared with preoperative biopsy in differentiating malignant and benign presacral tumors.

Methods/Interventions: Adult patients at a multi-center institution with solid or heterogeneous presacral tumors undergoing surgical resection from January 2011 – December 2023 who had a preoperative biopsy were identified. Demographics, imaging, biopsy modality and complications, operative data, and recurrence were collected via retrospective record review. Positive predictive value (PPV), negative predictive value (NPV), specificity and sensitivity were calculated.

Results/Outcomes: Sixty-three patients with presacral tumors underwent preoperative biopsy. Thirty patients (47.6%) were female. Average age at the time of resection was 50.6 years (SD 14.3). Forty-two patients (66.7%) had both a CT and MRI, 12 (19.1%) had MRI alone, 7 (11.1%) had CT alone, and imaging modality was unknown for two patients. Forty-nine patients (77.8%) had a CT-guided biopsy, 4 (6.3%) had an ultrasound-guided biopsy, and 2 (3.2%) had an open biopsy performed. The biopsy imaging modality was unknown in 8 (12.7%) patients. Of the patients who had a percutaneous biopsy, 36 (57.1%) had a fine needle aspirate (FNA) and 27 (42.9%) had a core needle biopsy. Most biopsies were performed transacrally or parasacrally (n=52, 82.5%). Prior to referral to our institution, 1 patient (1.6%) underwent transabdominal biopsy, 2 (3.2%) underwent transrectal, and in 8 (12.7%) patients the approach was unknown. No biopsy-related complications were reported. Neoadjuvant therapy was administered to 17 patients (27.0%). At the time of surgery, the biopsy site was excised in 35 patients (55.6%). In 9 patients (14.3%), the biopsy site was not excised, and excision was unspecified in 19 cases (30.1%). All patients had an R0 resection with the exception of one who had a planned R2 procedure for palliation. At a mean follow up time of 2.9 years (SD 3.9), 57 patients (90.5%) were alive. Eleven patients (17.7%) who had initially undergone an R0 resection developed recurrent disease. Biopsy diagnosis correlated with histopathology in 51 patients (81.0%). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of tumor biopsy in differentiating malignant and benign diseases were 92.1%, 96.0%, 97.2% and 88.9%, respectively. The combined sensitivity, specificity, PPV and NPV of CT and MRI in differentiating malignant and benign disease were 96.6%, 58.8%, 80.0% and 90.9%, respectively.

Conclusion/Discussion: Biopsy for heterogenous or solid presacral tumors is safe. Although imaging demonstrates at least comparable sensitivity and NPV to tissue biopsy in differentiating malignant and benign disease, the much higher specificity and PPV of biopsies supports its superior diagnostic accuracy and utility in the preoperative management of these tumors when neoadjuvant therapy and more extensive surgery may be considered.