In a Danish population–based study reported in the Journal of Clinical Oncology, Jakobsen et al found that patients with diffuse large B-cell lymphoma (DLBCL) in first remission and event-free at 24 months after treatment have a low loss of residual lifetime compared with the general population.
The study included 1,621 patients aged ≥ 16 years from the Danish Lymphoma Registry who were newly diagnosed between 2003 and 2011 and who had complete remission or complete remission-unconfirmed after first-line R-CHOP (rituximab [Rituxan] plus cyclophosphamide, doxorubicin, vincristine, and prednisone) or R-CHOP–like therapy.
Reduction in Residual Lifetime
Overall survival at 5 years posttreatment was lower in patients with DLBCL vs the matched general population (78% vs 87%, standardized mortality ratio [SMR] = 1.75, P < .001). Standardized mortality ratios were reduced to 1.27 (P < .001) among patients with posttreatment event-free survival for 24 months and to 1.32 (P < .001) among those with 48-month event-free survival. For patients aged < 50 years who achieved 24-month event-free survival, 5-year overall survival was 99% vs 99% in the general population (SMR = 1.11, P = .99); patients aged ≥ 50 years had reduced survival, even among those with 60-month event-free survival (SMR = 1.36, P = .001).
Among all patients, residual lifetime was reduced by 1.07 months/year within the first 10 years after treatment compared with the general population. The average loss was 0.31, 0.29, and 0.29 months/year among those achieving 24-, 36-, and 48-month event-free survival, respectively. Competing risks analysis showed that excess mortality among patients decreased when death due to relapsed lymphoma was analyzed as a competing event vs death from other causes, suggesting that the excess mortality is explained by early and late relapse. The 5-year risks of relapse after achieving 24-month event-free survival were 4%, 7%, and 10% among patients aged < 50, 50 to 60, and > 60 years, respectively.
The investigators concluded: “Although this population-based study does not support complete normalization of survival for patients with DLBCL achieving [post-treatment event-free survival of 24 months], the estimated loss of residual lifetime was low for patients in continuous remission 2 years after ending treatment. Therefore, [post-treatment 24-month event-free survival] is an appealing and relevant milestone for patient counseling and could be a surrogate end point in clinical trials.”
The study was supported by the Danish Lymphoma Group.
Lasse Hjort Jakobsen, MSc, of Aalborg University Hospital, is the corresponding author of the Journal of Clinical Oncology.
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