Clinical characteristics and treatment outcomes of Chinese diffuse large B-cell lymphoma patients in the era of rituximab (2005–2018)

Background

Rituximab combined with cyclophosphamide, doxorubicin hydrochloride, vincristine, and prednisone (R–CHOP) regimen has improved the survival of diffuse large B-cell lymphoma (DLBCL) patients worldwide, compared with CHOP alone. Several limitations were seen in previous studies of Chinese DLBCL patients treated with R–CHOP or R-CHOP-like regimens. This study aimed to investigate the clinical characteristics and treatment outcomes of Chinese DLBCL patients treated with the standard first-line treatment.

Methods

Clinical data were collected from DLBCL patients who received frontline R–CHOP or R-CHOP–like regimens at the Cancer Hospital Chinese Academy of Medical Sciences & Peking Union Medical College (CHCAMS) between January 1, 2005, and December 31, 2018. The treatment outcomes were compared with those of patients diagnosed with DLBCL between 2004 and 2017 and who received immunochemotherapy from the United States Surveillance, Epidemiology, and End Results (SEER) database. Survival rates were estimated using the Kaplan–Meier method and compared using the log-rank test. Multivariate analysis of progression-free survival (PFS) and overall survival (OS) was performed using Cox proportional hazard regression.

Results

Overall, 1084 patients from the CHCAMS and 4013 patients from the SEER database were included in the study. As of April 30, 2022, the median follow-up period for the CHCAMS group was 87.3 (range: 0.5–195.4) months. For the CHCAMS group, the 5-year PFS and OS rates were 61.7% (95% confidence interval [CI]: 58.8–64.7%) and 70.6% (95% CI: 67.8–73.4%), respectively. For the SEER group, the 5-year OS rate was 66.5% (95% CI: 65.0–68.0%), which was inferior to that of the CHCAMS group (P ​< ​0.001). After adjusting for clinical factors and treatment, no significant difference was observed in the OS between the CHCAMS and SEER groups (P ​= ​0.867). In the CHCAMS group, multivariate analysis showed that an Eastern Cooperative Oncology Group performance status score ≥2, presence of B symptoms, Ann Arbor stage III–IV, elevated serum β2-microglobulin levels, and bulky mass were independent adverse prognostic factors affecting PFS and OS (P ​< ​0.05). Additionally, patients aged over 60 years, elevated lactate dehydrogenase levels, and more than two extranodal sites were independent adverse prognostic factors for OS (P ​< ​0.05). Local radiotherapy was significantly associated with better PFS (P ​< ​0.001) and OS (P ​= ​0.001).

Conclusion

After adjusting for clinical and treatment-related factors, no significant difference was observed in the 5-year OS rate between Chinese DLBCL patients treated with standard first-line treatment and those from the SEER database.