Excellent outcomes and lack of prognostic impact of cell of origin for localized diffuse large B‐cell lymphoma in the rituximab era

Summary Therapeutic options for limited‐stage diffuse large B cell lymphoma ( DLBCL ) include short‐ or full‐course R‐ CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) ± radiotherapy. The optimal treatment remains unclear. The prognostic value of cell‐of‐origin ( COO ) in early stage DLBCL is unknown. Patients with limited‐stage DLBCL (stage I or stage II , non‐bulky) treated with R‐ CHOP  ± involved field radiotherapy ( IFRT ) from 1999 to 2012 were included. COO by the Hans algorithm was analysed in a subset of patients. Of 261 patients, 30% were stage I ( N  = 82), 37% stage IE ( N  = 96), <1% stage IXEE ( N  = 1), 18% stage II ( N  = 46) and 14% stage IIE ( N  = 37). The stage‐modified International Prognostic Index stratified patients into prognostically relevant groups. There was no significant difference in progression‐free survival ( PFS ) or overall survival ( OS ) for patients in the germinal centre B‐cell‐like ( GCB ; n  = 65) and non‐ GCB cohorts ( n  = 22). Seventeen patients received R‐ CHOP  × 3–4 cycles (Arm A), 147 received R‐ CHOP  × 3–4 cycles +  IFRT (Arm B), 48 received R‐ CHOP  × 6 cycles (Arm C), and 50 received R‐ CHOP  × 6 cycles +  IFRT (Arm D). The outcomes were excellent, with 5‐year PFS of 82% and 5‐year OS of 93%, and were similar across the 4 treatment groups. In the rituximab era, outcomes for limited‐stage DLBCL , regardless of treatment approach, were excellent. Baseline COO was not a significant prognostic factor in patients treated with short‐course R‐ CHOP  +  IFRT .