Has the Level of Evidence of Podium Presentations at the Musculoskeletal Tumor Society Annual Meeting Changed Over Time?

BACKGROUND: Level of evidence (LOE) framework is a tool with which to categorize clinical studies based on their likelihood to be influenced by bias. Improvements in LOE have been demonstrated throughout orthopaedics, prompting our evaluation of orthopaedic oncology research LOE to determine if it has changed in kind. QUESTIONS/PURPOSES: (1) Has the LOE presented at the Musculoskeletal Tumor Society (MSTS) annual meeting improved over time? (2) Over the past decade, how do the MSTS and Orthopaedic Trauma Association (OTA) annual meetings compare regarding LOE overall and for the subset of therapeutic studies? METHODS: We reviewed abstracts from MSTS and OTA annual meeting podium presentations from 2005 to 2014. Three independent reviewers evaluated a total of 1222 abstracts for study type and LOE; there were 577 abstracts from MSTS and 645 from OTA. Changes in the distributions of study type and LOE over time were evaluated by Pearson chi-square test. RESULTS: There was no change over time in MSTS LOE for all study types (p = 0.13) and therapeutic (p = 0.36) study types during the reviewed decade. In contrast, OTA LOE increased over this time for all study types (p < 0.01). The proportion of Level I therapeutic studies was higher at the OTA than the MSTS (3% [14 of 413] versus 0.5% [two of 387], respectively), whereas the proportion of Level IV studies was lower at the OTA than the MSTS (32% [134 of 413] versus 75% [292 of 387], respectively) during the reviewed decade. The proportion of controlled therapeutic studies (LOE I through III) versus uncontrolled studies (LOE IV) increased over time at OTA (p < 0.021), but not at MSTS (p = 0.10). CONCLUSIONS: Uncontrolled case series continue to dominate the MSTS scientific program, limiting progress in evidence-based clinical care. Techniques used by the OTA to improve LOE may be emulated by the MSTS. These techniques focus on broad participation in multicenter collaborations that are designed in a comprehensive manner and answer a pragmatic clinical question.

Rare Case of Diffuse Skeletal Fluorosis Due to Inhalant Abuse of Difluoroethane.

CASE: We present a rare case of diffuse skeletal fluorosis in a 56-year-old man with a history of inhalation and topical abuse of aerosolized dust cleaner containing difluoroethane and prior industrial exposure to chlorofluorocarbon-rich organic solvent cleaners. This patient had diffuse osteosclerotic bone disease on radiographs that elicited concern for a potentially aggressive physiologic or pathologic process, until increased fluoremia was identified as the cause. Management was conservative with removal of the causative agent. CONCLUSION: Skeletal fluorosis is an osteosclerotic bone disease caused by excessive ingestion of fluoride. Although this pathology is endemic in some parts of the world where drinking water contains high levels of fluoride, it should be considered as a differential diagnosis for patients with characteristic radiographic findings and a history of inhalant abuse. Chronic exposure to chlorofluorocarbon-rich products should also be considered.

The Impact of Microenvironment on the Synovial Sarcoma Transcriptome.

Synovial sarcoma (SS) is initiated by a t(X;18) chromosomal translocation and resultant SS18-SSX fusion oncogene. Only a few SS cell lines exist. None has been compared to its source tumor. In order to compare matched tumor and cell line pairs, we performed RNAseq on 3 tumor/cell line pairs from a genetically engineered mouse model of SS, as well as 2 pairs from human SS tumors. Transcriptomes of mouse tumors and derivative cell lines deviated significantly. Differentially expressed genes highlighted inflammatory infiltrates and metabolism. The same was found for the human tumor and cell line pairs. More was shared between different tumors than between any tumor and its cell line. Direct xenografting generated transcriptomes that more closely resembled the primary tumor than did its derivative cell line. SS tumor transcriptomes are powerfully impacted by the environment wherein they reside, especially with regard to immune interaction and metabolism.

Extremity Soft Tissue Sarcoma: Tailoring Resection to Histologic Subtype.

Soft tissue sarcomas comprise tumors originating from mesenchymal or connective tissue. Histologic grade is integral to prognosis. Because sarcoma management is multimodal, histologic subtype should inform optimum treatment. Appropriate biopsy and communication between surgeon and pathologist can help ensure a correct diagnosis. Treatment often involves surgical excision with wide margins and adjuvant radiotherapy. There is no consensus on what constitutes an adequate margin for histologic subtypes. An appreciation of how histology corresponds with tumor biology and surgical anatomic constraints is needed for management of this disease. Even with the surgical goal of wide resection being obtained, many patients do not outlive their disease.

ß-catenin stabilization enhances SS18-SSX2-driven synovial sarcomagenesis and blocks the mesenchymal to epithelial transition.

ß-catenin is a master regulator in the cellular biology of development and neoplasia. Its dysregulation is implicated as a driver of colorectal carcinogenesis and the epithelial-mesenchymal transition in other cancers. Nuclear ß-catenin staining is a poor prognostic sign in synovial sarcoma, the most common soft-tissue sarcoma in adolescents and young adults. We show through genetic experiments in a mouse model that expression of a stabilized form of ß-catenin greatly enhances synovial sarcomagenesis. Stabilization of ß-catenin enables a stem-cell phenotype in synovial sarcoma cells, specifically blocking epithelial differentiation and driving invasion. ß-catenin achieves its reprogramming in part by upregulating transcription of TCF/LEF target genes. Even though synovial sarcoma is primarily a mesenchymal neoplasm, its progression towards a more aggressive and invasive phenotype parallels the epithelial-mesenchymal transition observed in epithelial cancers, where ß-catenin's transcriptional contribution includes blocking epithelial differentiation.