Review of Adamantinoma Tumor Characteristics and Treatments in the National Cancer Database (NCDB/NCD)

Abstract

Background: Adamantinomas are rare low-grade malignant bone tumors of uncertain origin, which manifest primarily in the anterior mid-tibial shaft. Growth is indolent with significant risk of delayed-onset recurrence and/or distant metastasis. The aim of this study is to describe the physical characteristics and treatments of adamantinomas in patients diagnosed through the NCDB. Methods: This is a retrospective study of all patients diagnosed with adamantinomas between 2004 and 2017 in the National Cancer Database. Adamantinomas were identified using ICD-O-3 code 9261. Description statistics and univariate Kaplan-Meier curves were performed using SPSS. No patients were excluded from analysis. Results: 97% of adamantinoma lesions were in the long bones of the lower extremities. Incidence was similar bilaterally, behavior was universally invasive, grade was 66.1% undetermined, stage was 63.7% stage 1, and mean diameter was 63.67 ± 42.8 mm. Only 2 instances of metastasis (bone) at diagnosis were recorded. Treatment was overwhelmingly surgery with an open approach radical excision or resection of the primary lesion with limb salvage and clean surgical margins regardless of tumor grade, stage, primary site, or size. 5, 10, and overall survival were 96.8%, 94.2%, and 92.9% respectively. Conclusion: Adamantinomas are rare slow-growing malignant tumors that primarily affect the anterior cortex of the tibia and have significant potential for recurrence and metastasis, thus should be treated with radical surgical resection and excision to obtain clear margins. Overall prognosis is favorable, but patients should be enrolled in a long-term surveillance program to periodically rule-out recurrence or metastasis.