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Risk stratification for central conventional chondrosarcoma of bone: A novel system predicting risk of metastasis and death in the Cancer Registry of Norway cohort
Author(s) -
Thorkildsen Joachim,
Taksdal Ingeborg,
Bjerkehagen Bodil,
Norum OleJacob,
Myklebust Tor Age,
Zaikova Olga
Publication year - 2020
Publication title -
journal of surgical oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.201
H-Index - 111
eISSN - 1096-9098
pISSN - 0022-4790
DOI - 10.1002/jso.25883
Subject(s) - medicine , proportional hazards model , hazard ratio , metastasis , cohort , soft tissue , oncology , chondrosarcoma , cancer registry , grading (engineering) , cancer , prognostic variable , pathology , confidence interval , civil engineering , engineering
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 high‐risk 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.