The role of radiotherapy in patients with refractory Hodgkin’s lymphoma after treatment with brentuximab vedotin and/or immune checkpoint inhibitors

Background:Approximately 10%–30%of patients with Hodgkin’s lymphoma(HL)experience relapse or refractory(R/R)disease after first-line standard therapy.Brentuximab vedotin(BV)and immune checkpoint inhibitors(ICIs)have important roles in the salvage treatment of R/R HL.However,subsequent treatment for HL refractory to BV and/or ICI treatment is challenging.Methods:We retrospectively analyzed patients in two institutions who had R/R HL,experienced BV or ICI treatment failure,and received radiotherapy(RT)thereafter.The overall response rate(ORR),duration of response(DOR),progression-free survival(PFS),and overall survival(OS)were analyzed.Results:Overall,19 patients were enrolled.First-line systemic therapy comprised doxorubicin,bleomycin,vinblastine,and dacarbazine(ABVD,84.2%);AVD plus ICIs(10.5%);and bleomycin,etoposide,doxorubicin,cyclophosphamide,vincristine,procarbazine,and prednisone(BEACOPP,5.3%).After first-line therapy,15(78.9%)and four patients(21.1%)had refractory disease and relapsed,respectively.After R/R HL diagnosis,six(31.6%),two(10.5%),and 11(57.9%)patients received BV and ICIs concurrently,BV monotherapy,and ICI monotherapy,respectively.All patients received intensity-modulated RT(n=12,63.2%)or volumetric modulated arc therapy(VMAT;n=7,36.8%).The ORR as well as the complete response(CR)rate was 100%;the median DOR to RT was 17.2 months(range,7.9–46.7 months).Two patients showed progression outside the radiation field;one patient had extensive in-field,out-of-field,nodal,and extranodal relapse.With a median follow-up time of 16.2 months(range,9.2–23.2 months),the 1-year PFS and OS were 84.4%and 100%,respectively.PFS was associated with extranodal involvement(P=0.019)and gross tumor volume(P=0.044).All patients tolerated RT well without adverse events of grade≥3.Conclusion:RT is effective and safe for treating HL refractory to BV or ICIs and has the potential to be part of a comprehensive strategy for HL.