In an analysis of data from SWOG studies reported in the Journal of Clinical Oncology, Stephens et al found as continued risk of relapse among patients with limited-stage diffuse large B-cell lymphoma (DLBCL) irrespective of whether they received CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) with or without radiotherapy or rituximab (Rituxan) plus CHOP with radiotherapy.
In the SWOG S8736 trial, 3 cycles of CHOP plus radiotherapy (CHOP3RT) improved 5-year progression-free and overall survival vs 8 cycles of CHOP (CHOP8) in patients with limited- stage DLBCL; however, subsequent analysis showed an overlap of the progression-free survival curves.
In the current analysis including 150 patients receiving CHOP8 and 158 receiving CHOP3RT in the trial, with a median follow-up of 17.7 years, median progression-free survival was 12.0 vs 11.1 years (P = .73), and median overall survival was 13.0 vs 13.7 years (P = .38). Progression-free survival was 69% vs 76% at 5 years, 55% vs 55% at 10 years, and 41% vs 40% at 15 years.
Rituximab and CHOP3RT
In an analysis of 56 patients with limited-stage DLBCL receiving rituximab and CHOP3RT in the SWOG S0014 study, with a median follow-up of 12 years, progression-free survival was 77% at 5 years and 58% at 10 years. Overall survival was 82% at 5 years and 67% at 10 years, with a persistent pattern of relapse being observed.
The investigators concluded: “Although 5-year [progression-free survival] and [overall survival] were improved after early analysis in patients with limited-stage DLBCL receiving CHOP3RT versus CHOP8, extended survival data showed similar [progression-free survival] and [overall survival], with continuous treatment failure. The addition of rituximab (S0014) to combined-modality therapy did not mitigate the continued relapse risk, underscoring the value of prolonged clinical trial patient observation and possible unique biology of limited-stage DLBCL.”
The study was supported by the National Institutes of Health (NIH)/National Cancer Institute (NCI)/National Clinical Trials Network grants and NIH/NCI Community Oncology Research Program grants.
Sonali M. Smith, MD, of the University of Chicago, is the corresponding author of the Journal of Clinical Oncology article.
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