[341] Evaluation of Small Kidney Masses in the Era of Tumor Ablation Therapy: How Accurate Is Rapid Cytological Diagnosis and Should Separation of the Diagnostic and Treatment Procedures Be Considered?

Sara M Barcia, Stephen M Nobles, Z Laura Tabatabai. University of California San Francisco, San Francisco, CA

Background: As ablative therapies assume a greater role in the management of small renal masses, accurate diagnosis of these lesions becomes increasingly important. At many institutions, including ours, ablation is performed immediately following rapid interpretation of fine needle aspiration biopsy (FNAB) of the mass. This study was undertaken to better understand the value of rapid interpretation performed in this setting, to compare its accuracy and correlation with the final diagnosis, and determine the percentage of patients who undergo treatment regardless of having a benign or non-definitive diagnosis in this setting.
Design: A 7-year retrospective review was performed to identify patients with small solid renal masses who underwent Ultrasound or CT guided FNAB immediately prior to percutaneous radiofrequency or cryoablation. The clinical and radiological characteristics, rapid cytopathologic interpretations by on-site cytopathologists or cytopathology fellows, number of passes performed, and final cytological diagnoses were recorded and analyzed.
Results: A total of 91 patients were identified. Tumor size ranged from 1 to 6.6 cm (mean 2.6 cm). The number of passes ranged from 1-4 (mean 2). At rapid interpretation, FNAB samples were satisfactory in 57 (63%), unsatisfactory in 24 (26%), and indeterminate in 8 (9%) of cases. Two cases lacked an adequacy statement. A definitive final diagnosis was obtained in 46 (80%) samples initially interpreted as satisfactory, 12 (50%) samples initially interpreted as unsatisfactory, and 4 (50%) samples initially interpreted as indeterminate. In 21 (23%) cases the final diagnosis was benign. Overall, a non-definitive final pathologic diagnosis was made in 27 (30%) of patients, and this was primarily due to insufficient material. A cytological diagnosis was provided at the time of rapid interpretation in 66 cases, 36 (55%) of which matched the final diagnosis.
Conclusions: In this setting, although on-site rapid cytopathologic diagnosis is less accurate than final diagnosis, performance of rapid assessment for sample adequacy plays an important role in increasing the rate of a definitive final diagnosis. Given that under the current approach a substantial number of patients with benign or indeterminate final diagnosis undergo ablation, modification of the current approach to separate the diagnostic and therapeutic procedures into separate settings should be considered if the diagnosis would alter clinical management.
Category: Cytopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 99, Monday Afternoon


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