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

Abstract

Background and Objectives: Interobserver variability in histological grading of central conventional chondrosarcoma (CCCS) limits the quality of patient information and research progression. We aim to quantify known and new prognostic variables and propose a risk stratification model. Method: We selected 149 cases from the Cancer Registry of Norway. Cox proportional hazard models were estimated. Based on these results a dichotomous risk classification was proposed and presented by Kaplan-Meier estimates for rates of local recurrence, metastasis, and disease-specific survival. Results: The influence of axial skeletal location (Hazard ratio [HR] = 19.06), a soft tissue component ≥1 cm (HR = 13.45), and histological grade 3 (HR = 16.46) are all significant in predicting the rate of metastasis. The creation of a variable combining axial skeletal location and a soft tissue component ≥1 cm strongly predicts the risk of metastasis (HR = 14.02; P < .001) and death (HR = 2.74; P = .030) at multivariate analysis, making the histological grade insignificant. Together with metastasis at diagnosis (HR = 285.65; P < .001), this forms the basis of our proposed risk stratification, producing a small highrisk group (39 cases with 33% risk of metastasis) and a large low-risk group (103 cases with 2% risk of metastasis) without a histological grade. Conclusion: Axial skeletal location and a soft tissue component ≥1 cm combined divides a CCCS cohort into low-and high-risk groups without a histological grade.

Chondrosarcoma-from Molecular Pathology to Novel Therapies

“…Due to the rare occurrence of these tumors, detailed data about their pathology and therapeutic management are still limited. The assessment of the prognostic factors reported in the literature is inconsistent due to the heterogeneity of the cohorts between studies and the fact that research is often limited only to a single institutional experience [ 17 , 97 ]. One of the nationwide studies conducted by Giuffrida et al [ 97 ] utilizing the Surveillance, Epidemiology and End Results (SEER) database with 2890 CHS cases indicated only two independent predictors of survival—histological grade and surgical stage.…”

“…Regardless of the aforementioned significance in establishing the prognosis, grading is a subject of interobserver variability [ 16 ]. Thorkildsen et al [ 17 ] proposed a novel system for risk stratification without the use of histological grade. The components of this system include the size of soft tissue component (< or ≥1 cm), axial or appendicular location, and presence of primary metastatic disease.…”

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

“…We have earlier reported disease‐specific survival (DSS) based on the CRN's “death from cancer/death from non‐cancerous cause” variable 13,27 . We found that this is not as disease specific as we would like in that DSS continued to fall from 5 to 10 years of observation despite no further LR or Met events.…”

“…“Oslo high risk” is defined as axial skeletal location combined with a soft tissue component more than or equal to 1 cm by standardized measurement and “Oslo low‐risk” as all extremity cases together with axial lesions that are intramedullary or have a soft tissue component less than 1 cm 27 . All ACT's are therefore part of “Oslo low risk.”…”

Establishment and validation of an individualized nomogram to predict distant metastasis in chondrosarcoma patients: a population-based study

“…According to Giuffrida et al (19), the rate of survival at 30 years in the low-grade group was significantly higher than that in the high-grade group (76% and 50%, respectively, P<0.05), in addition, patients in the highgrade group had an elevated death rate in the first decade, after that the survival began to stabilize. According to Thorkildsen et al (29), high-grade tumors (II or III) were linked to higher risks of metastasis (grade II vs. grade I: HR =3.90; grade III vs. grade I: HR =16.46, P<0.05). In highgrade malignancies, the structures of tumor cells and tissues are vastly abnormal-looking, as a result, it is generally more likely to develop and extend.…”