Predictors of Poor Response to Salvage Chemotherapy in Relapsed/ Refractory Pediatric Hodgkin Lymphoma- A Retrospective Analysis from Tertiary Cancer Centre in India

ABSTRACT

Background: Previous studies identified prognostic factors for survival in relapsed pediatric Hodgkin lymphoma (HL) who received salvage chemotherapy followed by autologous stem cell transplant (ASCT). However, data regarding predictors of poor response to salvage chemotherapy is limited. Methods: We conducted retrospective study in all relapsed HLtreated from January 2003 to December 2013. Logistic regression analysis was done to identify predictors of response to salvage chemotherapy. Cox regression analysis was done to identify prognostic factors for Freedom from treatment failure (FFTF) and overall survival (OS). Results: Forty six patients had relapsed HL. Among 45 patients who received salvage chemotherapy only 34 (73.4%) underwent ASCT. Stage 4 disease (p=0.02) and bulky disease at relapse (p=0.03) were predictors of poor response to salvage chemotherapy. FFTF and OS at 5 yr for entire cohort were 50.1% and 63.3%, respectively, while the same for patients who underwent ASCT were 66.3% and 80.7%, respectively. Among ASCT patients, those who had primary refractory /early relapse [HR-4.7, (95% CI-1, 22); p=0.05] had significant impact on 5 yr FFTF whereas disease status at transplant (CR vs. No CR) had significant impact on 5 yr OS [HR-4.6, (95% CI-1.03, 20.5); p=0.04]. Conclusions: Identification of predictors of poor response to salvage chemotherapy is an unmet need in the management of pediatric HL since complete response (CR) before transplant is independent predictor of survival. Stage 4 and bulky disease at relapse are high risk factors to predict incomplete response. Future trials should explore newer agents for effective salvage for these patients to attain complete response before ASCT.