Very late relapse in Hodgkin lymphoma: Characterizing an understudied population

Very late relapse (VLR) occurring >5 years after initial diagnosis is an uncommon event in the management of Hodgkin lymphoma (HL). Limited information regarding risk factors and optimal therapy is available.We reviewed patients treated for HL at Princess Margaret Cancer Centre, Toronto, Ontario Canada between January 01, 1999 and 31 December 31, 2018.Thirty-two patients experienced VLR. Median time to first relapse was 7.2 years. Most patients were treated with CMT both at initial diagnosis and relapse. Male gender (P = .04) and increased age at initial diagnosis (P = .008; HR 1.09 (95% CI: 1.02-1.15)) were identified as risk factors for inferior survival on univariate analysis. Stage, histology, treatment modality and risk assessment at diagnosis or relapse did not have a significant impact on survival outcomes. ASCT at first relapse had no impact on time to second progression (HR 1.72; 95% CI, 0.35-8.53; P = .51) or overall survival from first relapse (HR 1.55; 95% CI, 0.3-8.03; P = .6).Our data aligns with the limited information available in VLR HL suggesting the negative impact of age and male gender on this rare event. Additionally, our data did not show benefit of ASCT at first relapse in terms of survival outcomes in this population, though this analysis is limited by small sample size. Further study of optimal therapy to prevent and treat VL in the era of novel agents is critical.