Conditional Survival of Extracranial Oligometastatic Patients Treated with Stereotactic Body Radiation Therapy (SBRT): An International Consortium Study
Menée à l'aide de données multicentriques 2006-2017 portant sur 1 033 patients présentant des oligométastases (durée médiane de suivi : 24 mois), cette étude analyse la survie conditionnelle après un traitement par radiothérapie corporelle stéréotaxique
Introduction: Prolonged survivorship is increasingly observed in patients with oligometastases (OM) treated with stereotactic body radiation therapy (SBRT). The purpose of this study was to study the conditional survival of OM patients, which can provide more detailed prognostic information over time by considering time already survived. Methods: A multi-institutional database consisting of 1,033 patients with OM (
≤
5 metastases) treated with SBRT between 2006 and 2017 was analyzed. Conditional overall survival (OS) and progression-free survival (PFS) in 3 years were obtained at multiple time points for all patients as well as by primary cancer type. Cox regression was used to determine trends in conditional OS/PFS. Changes in the predictors of OS and PFS over time were also determined by multivariable Cox regression. Results: Median follow-up was 24 months (0.3-105 months). Three-year OS and PFS at baseline were 56.7% and 23.2%, respectively. OS in 3 years conditional on having survived for 3, 6, 12, and 24 months did not significantly change over time (56.7%, 55.4%, 55.8% and 50.6%, respectively; p = 0.60). In contrast, PFS probability in 3 years conditional on having survived progression-free for 3, 6, 12 and 24 months significant increased over time (23.6%, 27.3%, 35.1% and 48.8%, respectively; p < 0.001). When stratified by primary site, conditional PFS significantly increased over time for patients with colorectal, breast and kidney cancer patients. Conditional OS remained stable for non-small cell lung cancer and kidney cancer patients but significantly decreased over time for prostate, breast and colorectal cancer patients. Changes in significant prognostic factors of OS and PFS over time were also observed. Conclusion: Conditional survival analysis of OM patients showed that as patients survived longer, their prognosis for further survival remained stable or decreased. However, those patients that survived longer without disease progression could expect increased PFS over time.
International Journal of Radiation Oncology, Biology, Physics 2022