Evaluation of prognostic factors affecting long and short term survival rates of Hodgkin's lymphoma patients using the cure fraction models

Background and Aim: This study aimed to analyze the factors affecting time and experience of relapse in the patients with Hodgkin's lymphoma, using cure fraction. Material and Methods: This retrospective study included all the patients diagnosed as Hodgkin's lymphoma in the Center for oncology and hematology in Shafa Hospital in Ahwaz City from 2002 to 2012. We used survival analysis and cure fraction models In order to answer the question, "why are some people in the study don’t experience recurrence?". We used mixture and nonmixture cure models using Weibull, exponential, log-normal, log-logistic and gamma distributions, and a logistic model for estimation of  the proportion of safe individuals; and Cureregr8 instruction for study of its associated factors. STATA13 software was used for data analysis. Akaike information criterion (AIC) was used to compare the performance of these models. Results:  Parametric model of Weibull distribution had the lowest AIC (804.3171).  Factors affecting long-term survival of the patients with Hodgkin's lymphoma, were hemoglobin > 10.5 (P-value = 0.018) and stage of the disease (P-value = 0.032). Factors affecting short-term survival of the patients included age >30 years (P-value = 0.001), involvement of the groin site (P-value = 0.010) Stage of disease (P-value < 0.001) and bone marrow involvement (P-value = 0.003). Conclusion: When the study population includes two susceptible and non-susceptible (safe or healed) subgroups in regard to recurrence of Hodgkin's lymphoma, use of cure models for separate evaluation of the variables associated with the long and short term survival and cure rates is appropriate.