Accuracy of histology and malignancy grade between preoperative biopsy and surgical specimens in primary retroperitoneal sarcoma. A study from the Prospective Retroperitoneal Sarcoma Registry (Resar).
Borghi, Alessandra Fiore, Marco Tiné, Gabriele Strauss, Dirk C Bonvalot, Sylvie Raut, Chandrajit P Rutkowski, Piotr Ford, Samuel Swallow, Carol J Gyorki, David E
Borghi, Alessandra
Fiore, Marco
Tiné, Gabriele
Strauss, Dirk C
Bonvalot, Sylvie
Raut, Chandrajit P
Rutkowski, Piotr
Ford, Samuel
Swallow, Carol J
Gyorki, David E
Affiliation
Fondazione IRCCS Istituto Nazionale dei Tumori; The Royal Marsden NHS Foundation Trust; Institut Curie; Brigham and Women's Hospital; Harvard Medical School; Maria Sklodowska-Curie National Institute of Oncology Center; University of Birmingham; Sinai Health System; University of Toronto; Peter MacCallum Cancer Centre; University of Melbourne; Ludwig-Maximilians-Universität Munich; University Hospital Munich; Humanitas University; IRCCS Humanitas Research Hospital; Emory University School of Medicine; Winship Cancer Institute; The Ottawa Hospital; University of Ottawa; The Ohio State University; European Institute of Oncology; Institute of Oncology Ljubljana; National Cancer Center Hospital Tokyo; Università degli Studi di Milano; University Hospitals Birmingham NHS Foundation Trust; Fondazione Policlinico Universitario Campus Bio-Medico
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Publication date
2025-12-22
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Abstract
Objective: This study aimed to prospectively assess the accuracy of preoperative biopsy in primary retroperitoneal sarcoma (RPS) across sarcoma referral centers.
Summary background data: Histological subtype and malignancy grade are key for guiding RPS treatment strategies. However, the accuracy of preoperative biopsy remains uncertain.
Methods: Data on adult patients with primary localized RPS who underwent preoperative biopsy followed by curative-intent surgery (2017-2020) were collected from the Retroperitoneal Sarcoma Registry. The study aimed to assess concordance between biopsy and surgical specimen histology and grade, using Cohen's kappa statistic. Concordance was also analyzed by center volume (high ≥13 vs. low <13 cases/year).
Results: Of 894 enrolled patients, histologic concordance was observed in 87.7% of cases (unweighted κ=0.814; 95% CI, 0.773-0.854). Among 172 tumors initially diagnosed as well-differentiated liposarcomas, 44 (25.6%) were reclassified as dedifferentiated liposarcomas. Grade concordance was observed in 232 of 346 cases (76.1%; weighted κ=0.652; 95% CI, 0.589-0.715), with no difference between computed tomography- and ultrasound-guided biopsies. Concordance by tumor grade was 98.9% (grade 1), 62.1% (grade 2), and 40.2% (grade 3). In dedifferentiated liposarcomas, grade concordance was 59.7% (weighted κ=0.385; 95% CI, 0.292-0.479). High-volume centers showed higher concordance for both histology (κ=0.780) and grade (κ=0.680) compared with low-volume centers (κ=0.622 and 0.564, respectively).
Conclusions: While preoperative biopsy for RPS provides satisfactory histologic accuracy, tumor grade is frequently underestimated. This diagnostic inaccuracy may impact treatment decisions, particularly regarding preoperative therapies. Incorporating additional diagnostic factors may improve the accuracy of preoperative assessment.
Citation
Borghi A, Fiore M, Tiné G, Strauss DC, Bonvalot S, Raut CP, Rutkowski P, Ford S, Swallow CJ, Gyorki DE, Albertsmeier M, Cananzi F, Cardona K, Nessim C, Grignol V, Pennacchioli E, Novak M, Iwata S, Salvatore D, Di Blasi E, Wilkinson M, Tzanis D, Wang J, Skoczylas J, Almond M, Gladdy RA, Mitchell C, Hayes A, Valeri S, Miceli R, Gronchi A; Transatlantic Australasian Retroperitoneal Sarcoma Working Group. Accuracy of Histology and Malignancy Grade between Preoperative Biopsy and Surgical Specimens in Primary Retroperitoneal Sarcoma. A Study from the Prospective Retroperitoneal Sarcoma Registry (Resar). Ann Surg. 2025 Dec 22. doi: 10.1097/SLA.0000000000007001. Epub ahead of print.
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Article