Prevalence of chemotherapy use and its impact on overall survival in patients with bone and soft tissue sarcomas: A population-based analysis of 3746 patients

Abstract

Background: The aims of this study were to understand the prevalence of chemotherapy (chemo) use and its associated impact on survival in patients (pts) with either bone- and soft-tissue sarcomas (STS) through a large real-world population dataset. Methods: A population-based retrospective database was assembled to extract pts with sarcoma, as defined as ICD-9-CM codes of bone (170.x) or/and soft tissue (171.x) who have attended clinics or hospitals of the Hong Kong Hospital Authority (HA) between Jan 2004 and Mar 2018. Eligible pts with index presentation of bone or/and soft tissue sarcoma (STS) on or after Jan 2005 were analysed to allow 1-year window. Drug dispensing records of chemotherapy drugs (chemo) from the HA as categorized by the British National Formulary 8.x were extracted and correlated with all-cause and cancer specific mortality. Results: Of 3746 pts identified, 3358 pts satisfied eligibility: bone: n = 661, STS n = 2576, both n = 121. 32.8% of pts (n = 1100) had chemo prescribed during the study period. The proportional use of chemo decreased with advancing age (<18y: 70.9%; 18-<40y: 42.2%; 40-65y: 36.1%, 65-80y: 19.7%;.>/=80y: 8.1%). Anthracyclines (AN) were the most commonly used class of chemo (19.8%), followed by alkylating drugs (17.3%), antimetabolites (11.9%) and vinca alkaloids & etoposide (8.7%). Comparing with pts who have not received chemo within the study period, the risk for death was higher in pts who have received AN either as first chemo (HR 1.51, 95%CI1.25-1.83; p < 0.001) or later lines of therapy (HR 1.55; 95%CI1.10-2.17; p = 0.002), and in pts who have had chemo but never received AN (HR 1.51; 95%CI1.27-1.80; p < 0.001). AN use resulted in significant reduction in mortality over non-AN chemo use if used within 3months of index diagnosis. This significance was not apparent in pts who started chemo >3months post diagnosis (log-rank p < 0.01 and p = 0.14 respectively). The impact of chemo on mortality reduction appeared greater in pts with bone- vs. STS. Conclusions: This is one of the largest assembled population-based real-world sarcoma cohort. Chemo use and choice of chemo has implications on survival. The positive effect on survival was especially prominent in pts with bone sarcomas.