Nonfluorodeoxyglucose-Avid Persistent Splenomegaly at Time of Transplantation Delays Neutrophil and Platelets Engraftment without Affecting Survival in Patients with Lymphomas Undergoing Allogeneic Hematopoietic Cell Transplantation

Abstract

It is unclear if persistent splenomegaly in the presence of a negative positron emission tomography (PET) scan before allogeneic hematopoietic cell transplantation (HCT) influences post-transplantation outcomes in patients with lymphoma. We retrospectively reviewed records of 152 patients who underwent allogeneic HCT for various lymphomas. Centralized review of pretransplantation computed tomography (CT) and PET images was performed. Spleen volume (SV) was measured using the freehand volume segmentation tool in AW Workstation software (General Electric, Waukesha, WI). Splenic index (SI) was calculated as a product of width, thickness, and length of the spleen. Normal SV was defined as SV < 314.5 cm³ and normal SI was defined as SI ≤ 480 cm³, as described in the literature. Among the study population, 42.8% received an allogeneic HCT from an HLA-matched related donor, 36.2% from a matched unrelated donor, 12.5% from a mismatched unrelated donor, and 8.6% received a double umbilical cord blood transplantation. Most (61.8%) received myeloablative conditioning. Median age at transplantation was 52 (range, 21 to 68) years. Pre-allogeneic HCT spleen CT and PET images were available on 88% and 70.3% patients, respectively. SV ranged from 90 cm³ to 4684 cm³ with a median of 290.5 cm³ and a mean of 400.3 cm³. SI calculation showed a range from 50.3 cm³ to 8276.4 cm³ with a median of 582.1 cm³ and a mean of 771.2 cm³. The majority of patients (83.1%) had PET-negative spleen before allogeneic transplantation. Engraftment was delayed in PET-negative patients with persistent splenomegaly, with median days to neutrophil engraftment of 17 versus 16 (P = .03) and median days to platelet engraftment of 16 versus 14 (P = .04) when using SV. However, persistent splenomegaly did not appear to impact progression-free survival (P = .11) or overall survival (P = .37). Splenomegaly in the setting of a PET-negative study before allogeneic HCT delays neutrophil and platelet engraftment but does not appear to affect survival. Future studies using registry data or larger multicenter studies would be required to evaluate the impact of splenomegaly and its fluorodeoxyglucose avidity on allogeneic HCT outcomes in specific subtypes of lymphomas.

Keywords: Engraftment; Hematopoietic cell transplantation; Spleen index; Spleen volume; Survival.