Secondary malignancies among mantle cell lymphoma patients.

PURPOSE: With modern treatments, mantle cell lymphoma (MCL) patients more frequently experience long-lasting remission resulting in a growing population of long-term survivors. Follow-up care includes identification and management of treatment-related late-effects, such as secondary malignancies (SM). We conducted a population-based study to describe the burden of SM in MCL patients.

METHODS

All patients with a primary diagnosis of MCL, aged ≥ 18 years and diagnosed between 2000 and 2017 in Sweden were included along with up to 10 individually matched population comparators. Follow-up was from twelve months after diagnosis/matching until death, emigration, or December 2019, whichever occurred first. Rates of SM among patients and comparators were estimated using the Anderson-Gill method (accounting for repeated events) and presented as hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age at diagnosis, calendar year, sex, and the number of previous events.

RESULTS

Overall, 1 452 patients and 13 992 comparators were followed for 6.6 years on average. Among patients, 230 (16%) developed at least one SM, and 264 SM were observed. Relative to comparators, patients had a higher rate of SM, HRadj= 1.6 (95%CI:1.4-1.8), and higher rates were observed across all primary treatment groups: the Nordic-MCL2 protocol, R-CHOP, R-bendamustine, ibrutinib, lenalidomide, and R-CHOP/Cytarabine. Compared to Nordic-MCL2, treatment with R-bendamustine was independently associated with an increased risk of SM, HRadj= 2.0 (95%CI:1.3-3.2). Risk groups among patients were those with a higher age at diagnosis (p < 0.001), males (p = 0.006), and having a family history of lymphoma (p = 0.009). Patients had preferably higher risk of melanoma, other neoplasms of the skin and other hematopoietic and lymphoid malignancies.

CONCLUSIONS

MCL survivors have an increased risk of SM, particularly if treated with R-bendamustine. The intensive treatments needed for long-term remissions are a concern, and transition to treatment protocols with sustained efficacy but with a lower risk of SM is needed.