Do Orthopaedic Oncologists Agree on the Diagnosis and Treatment of Cartilage Tumors of the Appendicular Skeleton?

Abstract

Background Distinguishing a benign enchondroma from a low-grade chondrosarcoma is a common diagnostic challenge for orthopaedic oncologists. Low interrater agreement has been observed for the diagnosis of cartilaginous neoplasms among radiologists and pathologists, but, to our knowledge, no study has evaluated inter-and intraobserver agreement among orthopaedic oncologists grading these lesions using initial clinical and imaging information. Determining such agreement is important since it reflects the certainty in the diagnosis by orthopaedic oncologists. Agreement also is important as it will guide future treatment and prognosis, considering that there is no gold standard for diagnosis of these lesions. Questions/Purposes (1) to determine inter-and intraobserver agreement among a multinational panel of expert orthopaedic oncologists in diagnosing cartilaginous neoplasms based on their assessment of clinical symptoms and imaging at diagnosis. (2) To describe the most important clinical and imaging features that experts use during the initial diagnostic process. (3) To determine interobserver agreement for proposed initial treatment strategies for cartilaginous neoplasms by this panel of evaluators. Methods Thirty-nine patients with intramedullary cartilaginous neoplasms of the appendicular skeleton of various histopathologic grades were selected and classified as having benign, low-grade malignant, or intermediate-or high-grade malignant neoplasms by 10 experienced orthopaedic oncologists based on clinical and imaging information. Additionally, they chose the three most important clinical or imaging features for the diagnosis of these neoplasms, and they proposed a treatment strategy for each patient. The Kappa coefficient (j) was used to determine inter-and intraobserver agreement. Results Inter-and intraobserver agreements were only fair to good, j = 0.44(95% CI, 0.41-0.48) and j = 0.62 (95% CI, 0.52-0.72), respectively. The three factors most frequently identified as helpful in making the diagnosis by our panel were cortical involvement in 65% of evaluations (253/390), neoplasm size in 51% (198/390), and pain in 50% (194/390). The interobserver agreement for the proposed initial treatment strategy after diagnosis was poor (j = 0.21; 95% CI, 0.18-0.24). Conclusions This study showed barely fair interobserver and fair to good intraobserver agreement for grading of intramedullary cartilaginous neoplasms by orthopaedic oncologists using initial clinical and imaging findings. These results reflect the insufficient guidance interpreting clinical and imaging features, and the limitations of the systems we use today when making these diagnoses. In the same way, they generate concern for the implications that this may have on different treatment strategies and the future prognosis of our patients. Future studies should build

Risk stratification for central conventional chondrosarcoma of bone: A novel system predicting risk of metastasis and death in the Cancer Registry of Norway cohort

“…The role of histological grading in the prognosis of chondrosarcoma (CS) of bone was first described over 50 years ago 1 . During the last 10 years, the inter‐observer variability of grading between expert pathologists, radiologists, and orthopedic oncologists and its clinical and research implications has been well documented 2‐5 …”

Chondrosarcoma local recurrence in the Cancer Registry of Norway cohort (1990–2013): Patterns and impact

“…If compared with only those where histology is available then the rate of upgrading is 3% (1/33) and dedifferentiation 6% (2/33). All methods produce low numbers when considering the rate of interobserver variation in CS assessment 22,23,36 . It is also possible that those not treated for their LR (7 of 40 cases) represent an undocumented upgraded cohort with more aggressive disease since we do not have operative specimen for grading for these patients.…”

“…Although the likelihood ratio‐test for their comparison is nonsignificant ( p = .068), we believe that the sum of evidence indicates that in the setting of LR, Oslo risk stratification from the primary treatment setting may give a useful dichotomous division of risk. If validated in larger numbers this gives us a readily available clinical tool to guide LR therapy free from the constraints of interobserver variability in both pathological grading and clinical assessment 36 . The “Oslo low risk” group represents 74% of the cohort and needs aggressive local therapy since they have a low chance of developing systemic disease and local control is achieved in 8 of 10 cases (80%).…”

“…All methods produce low numbers when considering the rate of interobserver variation in CS assessment. 22,23,36 It is also As such it is possible that their increased sampling or attention can lead to an increased level of recognition of higher grade areas in a heterogeneous tumor.…”

Systematic approach to musculoskeletal benign tumors

“…One such example is the tibia, which in addition to hosting most tumors that one can think of, also is the most common location for 3 uncommon tumors, adamantinoma 10 , ossifying fibroma, and chondromyxoid fibroma 11 . Other categorizations of particular bone involvement might be useful such as axial versus appendicular or flat versus tubular bones, with many lesions clearly favoring one over the other 12 , 13 . It is worthwhile to categorize a lesion’s location in the transverse axis of a tubular bone (central, eccentric, or a cortically based epicenter) 14 .…”