Chondrosarcoma in Norway 1990–2013; an epidemiological and prognostic observational study of a complete national cohort

Abstract

Background: Knowledge of chondrosarcoma (CS) of bone to date is based on institutional reports and registry publications with limits in reporting, detail and quality of data. Method: We have performed a retrospective search of CS of bone in the National Cancer Registry in Norway from 1990-2013, cross checked against local tumor databases with further quality control and supplementation of all data from clinical files. The time period is defined by the routine use of axial imaging in clinical practice. A total of 311 cases are included. We performed 108 pathological reviews and 223 radiological reviews. The manuscript was prepared according to the STROBE checklist for strengthening of observational studies. We performed uni-/multivariate cox analyses to define independent prognostic variables from the main cohort of central CS of bone. Results: The incidence of CS of bone in Norway is 2.85/million/yr. for both sexes overall, rising to 3.45/million/yr. in the last 5-year period. There is an increase in the most common central CS subtype, stronger for women than for men. Central CS had, in general 10-15% local recurrence rates, all evident by 5 years while metastasis rate increases with location and grade. Exceptions are extremity grade 1 CS which displayed no metastatic events and axial grade-3 disease with high rates (50%) of both local and metastatic relapse. Peripheral CS had limited metastatic potential (2%), but rates of local relapse (13%) continue to appear towards 10 years of follow up. Malignancy grade 3 independently predicts rate of metastasis and presence of soft tissue component predicts local recurrence, metastasis and survival. Conclusion: Rates of local recurrence, metastasis and disease specific survival follow clear patterns depending on subtype, location and grade allowing better tailoring of follow-up regimes. Malignancy grade 3 and the presence of a soft tissue component independently predict behavior for central CS of bone. ARTICLE HISTORY

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 Cancer Registry of Norway (CRN) cohort of CS of bone from 1990 to 2013 has been previously described, and the same definitions were applied to this study 14 (Supporting Information Material). It is a prospective register, but we have retrospectively quality controlled all data.…”

“…These results are generally in mixed cohorts, and include central, peripheral, and often dedifferentiated CS subtypes 1,8‐13 together. Though these subtypes have similar features on microscopic examination, 14‐16 they are now recognized as different diseases with varying biology and treatment 17 and as such, the prognostic work should also be performed at a subtype level.…”

“…Many cohorts with central conventional chondrosarcoma (CCCS) alone are limited to specific anatomical locations or with multivariate analyses for limited variables in institutional cohorts 6,7,18 . Histological grade significantly predicts survival at univariate analysis in two national CCCS cohorts, 14,19 but has not been proven in multivariate models. Neither does it convey the established importance of anatomical location and soft tissue extension which drives treatment of CCCS 17…”

“…We have previously shown the prognostic importance of a soft tissue component in CCCS of bone 14 . We, therefore, chose to look at whether the soft tissue components’ size by standardized measurement was associated with prognosis.…”

“…Our primary aim was to use prognostic analysis from a complete national cohort of CCCS of bone 14 to quantify the influence of anatomical location, presence, and size of a soft tissue component, as well as malignancy grade.…”