A Mixture Cure Model For Interval Censorship With A Change Point Based on Age Threshold in Hodgkin Lymphoma Patients After Stem Cell Transplantation

Introduction: hodgkin lymphoma (hl) is one of the most curable cancers. a bulk of studies have validated the benefits of hematopoietic stem cell transplant (hsct) for patients with relapsed or primary resistant hl. this analysis aimed to identify an effective change point in patients’ ages, the cure fraction before and after the change point, and significant prognostic factors on the cure fraction before and after the change point for such patients after hsct in iran. materials and methods: in this retrospective cohort study, there were 156 patients with hl who underwent hsct from 2007 to 2014 with 18 months of a follow-up in tehran, iran. the survival time was set as the time interval between transplantation and the recurrence of hl. also, the change point and the cure fraction before and after the change point were estimated using the bayesian estimation method and log-normal distribution. results: out of 156 individuals with hl who underwent stem cell transplantation, 77(49.4%) were male, and 79(50.6%) were female with the mean±sd age of 30.3±8.99 and 29.3±8.16 at the time of transplantation, respectively. the estimated cure fraction was 79.2% for all patients. the effective change point in age was 35 years, and the cure fraction before and after the change point was 84.5 % and 60.6%, respectively. the best subset of variables related to the model in question include white blood cells and hemoglobin; none of these variables were statistically significant before and after the change point. conclusion: the study concluded that the age of 35 years is a significant change point in age at the time of transplantation. if individuals undergo hsct with hl before the age of 35, they have a higher survival rate (recurrence of hl) than those who do so afterwards.