Incidence of secondary malignancies (SM) in patients (pts) with germ cell tumors (GCT) who received high-dose chemotherapy (HDCT): A retrospective study from the European Society for Blood and Marrow Transplantation (EBMT) database.

Abstract

4549 Background: Little is still known about the incidence of SM in young adult pts with GCT after HDCT, owing to the rarity of the disease, and the need for registries with long term follow-up (FUP) data. In Europe, the EBMT may provide a suitable platform for such retrospective analyses. Methods: Criteria for patient selection included diagnosis of GCT, adult male gender, ≥2yr of FUP after the administration of HDCT. Summary statistics were used to describe pt characteristics and outcomes. χ2 tests were used to compare groups according to the length of FUP. Kaplan-Meier estimates were used to estimate overall survival (OS). Univariable Cox regression analyses examined clinical factors potentially associated with OS. Survival times were calculated from the HDCT administration date. To estimate the probability of developing SM, the cumulative incidence of SM was calculated for all pts. Results: From 1981 to 2014, 9,153 autografts, accounting for 5,100 pts, have been registered. Of them, 1,855 had ≥2yr of FUP. Among the latter, a total of 56 cases of SM were identified (3.0%). 28 (50%) had solid SM, 22 (39.3%) hematologic (hem) SM (5 had uncoded SM). Median age at first HDCT was 34 years (IQR: 30-42), median age at development of SM was 42 (37-51). 26 pts (46.4%) received single HDCT cycle, 22 (39.3%) multiple HDCT cycles (8 unknown). 31 pts had ≥5 yr FUP, 25 pts 2-5 yr FUP. The median latency of SM was 3.3yrs (IQR: 1.8-6.1) for hem SM and 5.6yrs (IQR: 1.2-10.8) for solid SM. Median FUP was 6.4yrs. Univariably, the type of SM (solid vs. hem) was significantly associated with OS. Hem vs solid SM: HR: 2.17 (95%CI: 1.19-4.97, p = 0.020). Median OS of pts who developed solid SM was 13.3yrs compared to 4.1yrs of those with hem SM. The retrospective nature of the data is the major limitation. Conclusions: In the largest European database of SM in GCT pts, we observed different trends for SM development according to the SM type. This information may be important for FUP guidelines of these pts. Dataset implementation is ongoing and we will compare the SM incidence from EBMT database with SM rates in the general EU population.