Effect of consolidation radiation therapy on treatment outcomes of early-stage favorable Hodgkin lymphoma

   Background. Early (stage I–II) classical Hodgkin lymphoma is a highly treatable malignant neoplasm. For many years, the standard treatment of early Hodgkin lymphoma has been combination therapy: polychemotherapy with subsequent consolidating radiation therapy.

   Aim. To retrospectively evaluate the results of treatment of stage I–II classical Hodgkin lymphoma in a favorable prognosis group using monotherapy and combination therapy (chemotherapy followed by consolidating radiotherapy).

   Materials and methods. The study included 58 patients aged 19–81 years (median age 36 years) diagnosed with stage I–II classical Hodgkin lymphoma with favorable prognosis; 23 (39.7 %) patients were men, 35 (60.3 %) were women. Depending on the treatment received, the patients were divided into two groups: 40 (69 %) patients received ABVD polychemotherapy, and 18 (31 %) patients received polychemotherapy followed by consolidating radiation therapy to the initial lesion zones with standard fractionation regimen (total dose 30 Gy). The Kaplan–Mayer method was used to evaluate overall, progression-free, recurrence-free, and event-free survival. Odds ratios and their 95 % confidence intervals were also calculated. The statistical significance of differences in survival was assessed using the log-rank test. The level of statistical significance was 0.05. Statistical data processing was carried out using the IBM SPSS Statistics 27 software and Microsoft Excel.

   Results. According to the results of our study, while in the total patient group a clear numerical advantage in survival (overall, progression-free, relapse-free and event-free survival) was observed in the combination therapy group compared to chemotherapy group (5.5, 13.2, 9.2 and 23.9 %, respectively), no preferred tactics were identified in the total patient group. However, considering a subgroup of patients with mediastinum involved in the tumor process, a statistically significant advantage of combined treatment over single-mode chemotherapy was determined for 2-year event-free survival (92.9 ± 6.9 % vs. 62.5 ± 9.9 %, respectively, p = 0.046). The risk of an adverse event is reduced by >80 % (odds ratio 0.197; 95 % confidence interval 0.036–0.977) when using consolidating radiation therapy after chemotherapy.