A population-based comparison of patients with diffuse large B-cell lymphoma (DLBCL) in first complete remission indicated that routine imaging surveillance did not improve outcomes, researchers reported.
Overall survival was similar for Danish and Swedish populations who received similar follow-up care, except that routine imaging surveillance is the standard of care in Denmark, but not in Sweden. The 3-year overall survival for Danish and Swedish patients was 92% and 91%, respectively.
Outcomes grouped by international prognostic index (IPI) also showed no significant differences between populations (J Clin Oncol. 2015 Oct 5, doi:10.1200/jco.2015.62.0229.).
“An imaging-based follow-up strategy does not improve postremission [overall survival] for DLBCL,” wrote Dr. Tarec Christoffer El-Galaly, of Aalborg University Hospital, Denmark, and colleagues.
They observed that aside from using IPI as risk stratification, the study “also points to baseline [lactate dehyrogenase] as a single discriminator of patients with high versus low risk of progression,” (Hazard ratio, 3.12; 95% CI, 1.78-5.48; P less than .01).
The retrospective study examined records of patients with DLBCL from Sweden (n=696) and Denmark (n=525) who achieved first complete remission after first-line therapy with R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) and CHOP-like regimens from 2007 to 2012. The proportion of patients with IPI greater than two were similar for both groups, though more Danish patients received radiotherapy compared with their Swedish counterparts (35% v. 9%).
Standard follow-up care after first complete remission is similar in Denmark and Sweden and typically includes symptom assessment, clinical examination, and blood tests at 3- to 4-month intervals for 2 years, and 6-month intervals in the third year. After 3 years, Swedish patients are seen annually for 2 years and then follow-up is ended for most patients. In Denmark, 6-month checks are continued until 5 years and then follow-up is usually ended. However, in Denmark guidelines support routine computerized tomography (CT) scans of the neck, abdomen, and thorax every 6 months for 2 years, which is not encouraged by guidelines in Sweden.
Early relapse detection aims to improve survival, and although low disease burden is associated with durable survival in patients treated for relapsed DLBCL, most studies show similar outcomes for imaging versus non-imaging detection. Additionally, previous retrospective studies that have reported survival differences based on relapse detection method are prone to lead-time bias, according to the researchers.
Given that a majority of patients with recurrent DLBCL experience symptoms before relapse, that elevated lactate dehyrogenase or abnormal physical examination may raise suspicion, and that exposure to ionizing radiation from medical imaging can lead to radiation-induced cancers, “routine imaging for DLBCL in first [complete remission] is not recommended,” the authors wrote.
The research was supported in part by the North Denmark Region. Dr. El-Galaly and coauthors reported having no financial disclosures.