Overview and Rationale
Orthopaedic tumors are generally considered to be rare entities seldom encountered by non–oncology-trained orthopaedic surgeons, primary care physicians, pediatricians, and surgeons. This notion is supported by the small number of fellows trained in orthopaedic oncology, typically 12 to 15 annually, the smallest of all of the orthopaedic subspecialties. A recent estimate of the distribution of orthopaedic oncologists suggests that there is one specialist per 1.6 million people in the United States (US). Furthermore, sarcoma, the quintessential primary malignancy of the connective tissue, accounts for only 1% of all cancers in adults and 15% in children. However, these numbers underestimate the true burden of all extremity tumors (including sarcoma, metastatic disease of bone, benign tumors, and tumor-like non-neoplastic conditions) and the commonality of encountering lesions of unknown etiology in a community clinical practice.
The American Cancer Society estimates that 12,750 new soft-tissue sarcomas would be diagnosed in the US in 2019. The American Academy of Orthopaedic Surgeons (AAOS) estimates that 50% of the new carcinoma cases in the US (approximately 1.2 million) will eventually metastasize to bone. A case series documenting the annual procedural volume of early-career orthopaedic oncologists suggested that the malignant entities, sarcoma and metastatic disease of bone, account for a minority of clinical evaluations by orthopaedic tumor specialists because 59% of the procedures are performed for benign entities. Additional reports of consecutive referrals to orthopaedic oncology practices found 70% to 72% of referrals were for lesions felt to be benign or non-neoplastic.[6,7] This also underestimates the number of clearly benign lesions in the population at large, such as lipomas and asymptomatic enchondromas, which are either unrecognized and therefore not evaluated, or managed without specialist referral. This substantial burden of musculoskeletal abnormality and the possibility of inappropriate use of healthcare resources or delayed diagnosis of an unrecognized or misinterpreted malignancy were the primary motivators for creating this guideline.
Three prospective case series over the last 2 decades have attempted to comment on the most appropriate imaging modalities to be done by referring practitioners before evaluation by a specialist in orthopaedic tumors.[6–8] This question is important to avoid over-imaging tumors of low-risk and quiescent biology, as well as recognizing tumors that are inherently aggressive and a threat to the survival of the afflicted. These previous reports demonstrated general agreement in the overuse of advanced imaging in orthopaedic tumors (MRI, CT, bone scan, and positron emission tomography [PET]), with benign bone tumors as the most common entity over-imaged. In addition, the studies' results demonstrated agreement in the propensity for physicians with orthopaedic training to overuse advanced imaging at the same rate as those without orthopaedic training, namely primary care practitioners, internists, pediatricians, general surgeons, and specialty surgeons. Finally, each report recommended that defined guidelines would assist practitioners to choose the best imaging modalities depending on the clinical presentation, physical examination, and appearance on plain radiographs.
In June 2015, the Evidence Based Medicine Committee of the Musculoskeletal Tumor Society identified the topic of imaging before referral to a musculoskeletal oncologist as one of interest and importance to orthopaedic surgeons, general surgeons, primary care physicians, advance practice providers, and any healthcare professional who may encounter a bone or soft-tissue tumor of unknown etiology in their practice. The Musculoskeletal Tumor Society secured matching funds in November of 2015 from the AAOS Board of Specialty Societies Quality and Patient Safety Action Fund, designed to identify important quality and patient safety initiatives, thus allowing the project to be financially secured through completion.
In April 2016, we formed a working group of representatives from the AAOS, the Musculoskeletal Tumor Society, and the American College of Radiology. The working group was selected after soliciting volunteers from the relevant societies, ensuring that no participant had any financial conflicts of interest consistent with AAOS policy. The first task for this group was to formulate our questions of interest using the standard "population, intervention, comparison, and outcome" (eg, "PICO") format. Once these 12 questions were agreed upon, an extensive literature review was performed by a medical librarian to identify all potentially relevant primary research manuscripts. The AAOS Evidence Based Medicine Unit then reviewed all abstracts and identified pertinent full-text articles for additional analysis and review of methodology and strength. In total, 9,978 abstracts were reviewed, 1,707 full-text articles were analyzed, and 158 articles were included to create the guidelines. Each recommendation contains the specific articles relevant to the question, the quality of the study, and comments from the workgroup regarding how they were interpreted. Readers are encouraged to access the complete guideline for a more comprehensive discussion.
We included articles of primary data only; review articles were excluded. Registry studies were included, given that they satisfied the other a priori inclusion criteria. We included retrospective noncomparative case series and case series of nonconsecutive enrollment; these were considered very low-quality data. The quality of evidence for each included report was assessed using modified versions of the GRADE and QUADAS instruments. We then determined the strength of the recommendation depending on the quality of the scientific reports from which the recommendation was drawn. For instance, if a recommendation was supported by two or more high-quality studies, the strength of the recommendation would be strong. In contrast, if the best evidence were from two or more moderate-quality studies, the strength of the recommendation would be moderate. Support from low-quality and very low-quality data would result in a limited strength of recommendation. Further detailed discussion on the methodology of assigning quality of literature and strength of recommendations is available in the full guideline. If there was no reliable supporting evidence, the working group had the opportunity to create a consensus statement based primarily upon expert opinion. The explanation of each topic also includes a section on future research with suggestions on how the data may be improved with further investigation.
These guidelines were created with the generalist, front-line practitioner in mind. The guidelines do not apply to imaging studies that may be necessary to completely characterize a known malignancy or clarify a subtle management decision; these decisions are left to the expertise of oncologic specialists at the treating centers. The target audience includes physicians, but also advanced practice practitioners (physician assistants and nurse practitioners), nurses, physical therapists, and anyone who may be involved in the initial evaluation of patients. Nonphysician providers are becoming increasingly important in modern delivery of care, and the recommendations apply to anyone making management decisions in patients with a musculoskeletal tumor.
J Am Acad Orthop Surg. 2019;27(22):e1001-e1008. © 2019 American Academy of Orthopaedic Surgeons