Ultrasonography-Guided Core Needle Biopsy in the Diagnostic Pathway of Pelvic Tumors.

IMPORTANCE: Accurate histologic diagnosis of pelvic tumors is essential for guiding appropriate management but often requires diagnostic surgery, which is associated with morbidity and treatment delays. Ultrasonography-guided core needle biopsy offers a minimally invasive alternative that may reduce surgical risks while providing reliable diagnostic information. OBJECTIVE: To assess the safety and diagnostic adequacy of ultrasonography-guided core needle biopsy in patients with pelvic tumors and to evaluate diagnostic accuracy, patient experience, and pain levels associated with the procedure. DESIGN, SETTING, AND PARTICIPANTS: This prospective, multicenter cohort study was performed from May 26, 2021, to December 31, 2024, at 4 high-volume gynecologic oncology centers (Leuven, Belgium; Rome, Italy; Prague, Czech Republic; and Stockholm, Sweden), with follow-up at 6 weeks after the procedure. Consecutive patients aged 18 years or older with a pelvic tumor undergoing ultrasonography-guided core needle biopsy for diagnostic purposes or inclusion in academic trials were included, and follow-up data were available for all participants. EXPOSURE: Ultrasonography-guided core needle biopsy performed via transvaginal, transrectal, or percutaneous approaches according to lesion location and clinical indication. MAIN OUTCOMES AND MEASURES: The primary outcomes were safety, as assessed by procedure-related complication rates within 6 weeks, and diagnostic adequacy of biopsy specimens. Secondary outcomes included diagnostic accuracy compared with subsequent surgical histology when available, patient-reported pain measured using a numeric rating scale (0-100), and overall patient experience assessed within 72 hours post procedure. Descriptive statistical and multivariable regression analyses were performed. RESULTS: Among 461 patients prospectively enrolled in the study, biopsies were performed on 463 lesions (transvaginal: 422 patients; median [IQR] age, 64 [53-73] years; transrectal: 11 patients; median [IQR] age, 78 [59-80] years; percutaneous: 30 patients; median [IQR] age, 58 [51-71] years). Procedure-related complications occurred in 60 patients (13.0%), all of which were minor; no patients required surgery or blood transfusion due to complications. Biopsy specimens were diagnostically adequate in 95.7% (95% CI, 93.4%-97.4%) of cases. In 166 cases with available subsequent surgical histology, diagnostic accuracy was 97.6% (95% CI, 93.9%-99.3%). Patient experience was favorable, with 378 of 402 patients (94.0%) rating their experience in the upper half of the scale. The median pain score was 20 (IQR, 10-50). CONCLUSIONS AND RELEVANCE: This cohort study of patients undergoing ultrasonography-guided core needle biopsy of pelvic lesions found the procedure to be safe, diagnostically adequate, and well-tolerated. These findings support the procedure's broader implementation in selected patients to reduce the need for diagnostic surgery and associated morbidity.