Second primary malignancy after rituximab-containing immunochemotherapy for diffuse large B cell lymphoma

Treatment-specific risk of subsequent malignant neoplasms in five-year survivors of diffuse large B-cell lymphoma

BACKGROUND

The introduction of rituximab significantly improved the prognosis of diffuse large B-cell lymphoma (DLBCL), emphasizing the importance of evaluating the long-term consequences of exposure to radiotherapy, alkylating agents and anthracycline-containing (immuno)chemotherapy among DLBCL survivors.

METHODS

Long-term risk of subsequent malignant neoplasms (SMNs) was examined in a multicenter cohort comprising 2373 5-year DLBCL survivors treated at ages 15-61 years in 1989-2012. Observed SMN numbers were compared with expected cancer incidence to estimate standardized incidence ratios (SIRs) and absolute excess risks (AERs/10 000 person-years). Treatment-specific risks were assessed using multivariable Cox regression.

RESULTS

After a median follow-up of 13.8 years, 321 survivors developed one or more SMNs (SIR 1.5, 95% CI 1.3-1.8, AER 51.8). SIRs remained increased for at least 20 years after first-line treatment (SIR ≥20-year follow-up 1.5, 95% CI 1.0-2.2, AER 81.8) and were highest among patients ≤40 years at first DLBCL treatment (SIR 2.7, 95% CI 2.0-3.5). Lung (SIR 2.0, 95% CI 1.5-2.7, AER 13.4) and gastrointestinal cancers (SIR 1.5, 95% CI 1.2-2.0, AER 11.8) accounted for the largest excess risks. Treatment with >4500 mg/m2 cyclophosphamide/>300 mg/m2 doxorubicin versus ≤2250 mg/m2/≤150 mg/m2, respectively, was associated with increased solid SMN risk (hazard ratio 1.5, 95% CI 1.0-2.2). Survivors who received rituximab had a lower risk of subdiaphragmatic solid SMNs (hazard ratio 0.5, 95% CI 0.3-1.0) compared with survivors who did not receive rituximab.

CONCLUSION

Five-year DLBCL survivors have an increased risk of SMNs. Risks were higher for survivors ≤40 years at first treatment and survivors treated with >4500 mg/m2 cyclophosphamide/>300 mg/m2 doxorubicin, and may be lower for survivors treated in the rituximab era, emphasizing the need for studies with longer follow-up for rituximab-treated patients.

Risk and outcome of acute myeloid leukaemia among survivors of primary diffuse large B-cell lymphoma: a retrospective observational study based on SEER database

OBJECTIVES

Survivors of diffuse large B-cell lymphoma (DLBCL) are at an increased risk of developing second primary malignancies. However, the risk of secondary acute myeloid leukaemia (sAML) has not been previously described in detail, and the outcomes of patients with sAML are also undiscovered compared with their de novo counterparts (de novo acute myeloid leukaemia, dnAML).

DESIGN

This study is a retrospective database study.

SETTING AND PARTICIPANTS

A total of 70 280 patients with primary DLBCL, diagnosed between 2000 and 2016, were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Another cohort with dnAML matching with sAML was also obtained from SEER database.

RESULTS

The standardised incidence ratio was 6.23 (95% CI: 5.50 to 7.03) for sAML among survivors of DLBCL. The estimated cumulative incidence of sAML was 0.61% 15 years after the diagnosis of DLBCL. Patients aged 60-74 years were more likely to have sAML than those <60 years (subdistribution HR (sHR)=1.417; 95% CI: 1.087 to 1.850), whereas patients aged ≥75 years were less likely to have sAML (sHR=0.648; 95% CI: 0.452 to 0.930). Patients with advanced-stage DLBCL were more prone to sAML than those with early-stage disease (sHR=1.307; 95% CI: 1.012 to 1.690). There was a significant difference of survival between patients with dnAML and those with sAML (HR=1.25; 95% CI: 1.01 to 1.53).

CONCLUSIONS

The risk of developing sAML after DLBCL is substantial. Patients aged 60-74 years and with advanced-stage are more prone to sAML. And, compared with their dnAML counterparts, patients with sAML have a worse prognosis.