Impact of Achieving Progression‐Free Survival 24 on Subsequent Overall Survival in Diffuse Large B‐Cell Lymphoma Patients

The impact of achieving progression-free survival at 24 months (PFS24) on subsequent survival in patients with diffuse large B-cell lymphoma (DLBCL) relative to the general population remains debatable. We assessed the impact of achieving PFS24 in newly diagnosed DLBCL patients using data from JCOG0601, a prospective study of DLBCL patients treated with R-CHOP. Among 409 eligible patients (median follow-up: 5.3 years), 334 (82%) achieved PFS24, whereas 66 (16%) did not. Patients who achieved PFS24 had significantly better overall survival (OS) than those who did not (median OS, not reached vs. 1.3 years; p < 0.001). Similar results were observed for PFS12 and PFS60. The OS for patients after achieving PFS24 or PFS60 was not markedly different from that of the age-, sex-, and calendar period-matched Japanese general population (PFS24: standardized mortality ratio [SMR] 1.29, 95% confidence interval [CI] 0.72-2.12, p = 0.39; PFS60: SMR 1.43, 95% CI 0.47-3.33, p = 0.55). Conversely, the OS for patients after achieving PFS12 was significantly worse than that of the general population (SMR 2.30, 95% CI 1.59-3.22, p < 0.001). The primary cause of death among patients who achieved PFS12 was DLBCL, whereas the mortality rate from DLBCL among those who achieved PFS24 or PFS60 was less than 5%. Multivariable analysis showed that having two or more extranodal involvements (OR 2.76 [95% CI 1.39-5.46], p = 0.004) was the only significant risk factor for failing to achieve PFS24. Our findings suggest that PFS24 can serve as an early endpoint of OS in patients with DLBCL.