EFS at 24 Months May Predict Overall Survival in PTCL

Andrew L. Feldman, MD

Patients with peripheral T-cell lymphoma (PTCL) are more likely to have superior overall survival (OS) if they have previously demonstrated event-free survival at 24 months (EFS24), according to findings published in the Journal of Clinical Oncology.

In an analysis of 775 patients with PTCL, 36% achieved EFS24 and 64% did not. Median OS was not reached, with a 5-year OS of 78% (95% CI, 73%-84%) for those who had EFS24. In contrast, among patients who progressed within the first 24 months, median OS was 4.9 months and 5-year OS was 11%, with a standardized mortality ratio (SMR) of 46.4 (95% CI, 41.8-51.3).

The 5-year risk of subsequent lymphoma relapse was 23% in patients who achieved EFS24. Survival after late relapse was poor, with a median OS of 10.3 months (95% CI, 5.7-19.1).

“Assessment of EFS24 stratifies subsequent outcome in PTCL. Patients with early relapse of PTCL have extremely poor subsequent survival,” study author Andrew L. Feldman, MD, Department of Laboratory Medicine and Pathology, Mayo Clinic, and coinvestigators wrote. “However, more than one-third of patients with PTCL remain in remission 2 years from diagnosis after initial chemotherapy and have encouraging OS rates, although survival remains significantly worse than the matched general population and risk of subsequent progression persists.

“The marked differences in OS in patients with PTCL who did and did not achieve EFS24 suggest that this endpoint may be useful for patient counseling and as an endpoint to assess novel biomarkers for risk stratification,” added the researchers.

Investigators prospectively enrolled patients diagnosed with PTCL at University of Iowa/Mayo Clinic Specialized Program of Research Excellence Molecular Epidemiology Resource (MER) from 2002 to 2012 (n = 138). Researchers also collected data in the Swedish Lymphoma Registry (SLR) on patients diagnosed with T-cell lymphomas from January 2000 to December 2009 (n = 422). Results in those cohorts were validated with data from 215 patients collected in the BCCA Lymphoid Cancer Database.

EFS was defined as the time from the date of pathologic diagnosis to progression after primary treatment, retreatment, or death from any cause. EFS24 was defined as being alive and event free 24 months after diagnosis. Subsequent OS was defined as time from achieving EFS24 (24 months after diagnosis) or time from progression in patients who did not achieve EFS24 to death from any cause. OS rates were compared with the age-, sex-, and country-matched general population.

The initial analysis from the MER and SWE cohorts included 560 patients. As in the combined cohort, 36% achieved EFS24 and 64% did not. Median OS after progression within the first 24 months was 5.3 months (95% CI, 3.8-6.2), with a 5-year OS of 10% and SMR of 44.7 (95% CI, 39.4-50.6). In contrast, median OS after achieving EFS24 was not reached, with a 5-year OS of 77% (95% CI, 71%-84%). Expected 5-year OS was 91% in the age-, sex-, and country-matched population (SMR, 3.40; 95% CI, 2.58-4.47).

Investigators added data from the BCCA cohort to increase sample size and confirm findings from the MER and SWE cohorts. As with MER and SWE cohorts, 36% of patients achieved EFS24. Median OS after progression within the first 24 months was 4.5 months (95% CI, 2.2-5.7), with a 5-year OS of 14% and SMR of 50.3 (95% CI, 42.1 to 60.1). Median OS after achieving EFS24 was not reached, with a 5-year OS of 81% (95% CI, 73%-91%). Expected 5-year OS was 92% in the age-, sex-, and country-matched population (SMR, 2.72; 95% CI, 1.79-4.13).

The researchers noted that patients aged 60 or younger (n = 137) had the most favorable outcomes after achieving EFS24, with a 5-year OS of 91% (versus 98% expected [control population]). Patients who received autologous stem cell transplantation (SCT) in first remission (n = 72) had a 5-year OS of 88% (vs 96% expected). Patients who did not receive autologous SCT who achieved EFS24 (n = 189) had a 5-year OS of 74% (vs 90% expected).

Maurer MJ, Ellin F, Srour L, et al. International assessment of event-free survival at 24 months and subsequent survival in peripheral t-cell lymphoma. J Clin Oncol [published online October 26, 2017]. doi: 10.1200/JCO.2017.73.8195.