Impact of Splenomegaly in the Presence of Negative PET FDG Avidity on Allogeneic Hematopoietic Cell Transplant Outcomes in Patients with Lymphoid Malignancies
Authors: Khimani Farhad , Jeong Daniel K. , Nishihori Taiga , Ayala Ernesto , Pidala Joseph A , Locke Frederick L. , Kenneth Gage , Chavez Julio C. , Anasetti Claudio , Kharfan-Dabaja Mohamed A. 
Published: October 2019

Abstract
Background: It is unclear if persistent splenomegaly prior to allogeneic hematopoietic cell transplant (allo-HCT) influences post-transplant outcomes for lymphoid malignancies. Our study explores the significance of splenomegaly along with splenic PET avidity and its impact on allogeneic HCT outcomes in patients with lymphoid malignancies.
Methods: We retrospectively reviewed records of patients who underwent allo-HCT for lymphoid malignancies (n=152) between 2008 and 2013 at the Moffitt Cancer Center. Clinical data were captured through our research database and were supplemented with individual patient electronic medical record review. Pre-transplant CT and PET images of all patients were reviewed. Spleen volume (SV) was measured using the freehand volume segmentation tool in AW Workstation software (General Electric, Waukesha, WI, USA) on CT images. Splenic index (SI) was calculated as a product of width (W), thickness (Th) and length (L) of the spleen. Normal SV and SI was defined as SV < 314.5 cm3 and SI ≤ 480 cm3 as described in the literature. Spleen and liver mean standardized uptake value (SUV) s were calculated to document spleen PET avidity using region of interest measurements over the spleen and liver with standard radiology techniques. Spleens with mean SUV of lower value than liver were considered negative. Statistical analysis was performed using SPSS v.21.0.
Results: Among the study population 42.8% received an allo-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 transplants. Most patients (61.8%) received myeloablative conditioning. Median age at transplantation was 52(range 21-68) years. Pre-HCT spleen CT and PET images were available on 88% (n=134) and 70.3% (n=107) patients, respectively. Spleen volumes ranged from 90 cm3 to 4684 cm3 with a median of 290.5 cm3 and a mean of 400.3 cm3. SI calculation showed SI ranging from 50.3 cm3 to 8276.4 cm3 with a median of 582.1 cm3 and a mean of 771.2 cm3. Majority of patients (83.1%) had PET negative spleen pre-HCT. Stratified analysis and survival plots were obtained based on pre-transplant SV, SI and spleen PET status. The 2-year overall survival (OS) and progression-free survival (PFS) were 57.3% and 44.9%, respectively for all patients. 2-year OS and PFS for patients with SV ≥ 314.5 cm3 was 57.6% (95%CI 44.2-68.8) and 43.2% (95%CI 30.7-55.1), respectively, whereas for patients with SV < 314.5 cm3 was 58.1% (95%CI 45.8-68.5) and 48.4% (95%CI 36.4-59.3), respectively, with no significant differences in OS (p=0.82) or PFS (p=0.63). There were no differences among higher SV or SI vs. normal SV or SI in PET positive population but among PET negative group there was a suggestion of a favorable OS and PFS with normal SV and SI. (Figures 1&2).
Conclusions: There were no significant associations between spleen size or spleen PET status and allo-HCT outcomes (PFS or OS) in patients with lymphoid malignancy. Sample size is limited in our study. Future studies using registry data or larger prospective studies are required to evaluate the impact of splenomegaly and its PET avidity on allo-HCT outcomes in lymphoid malignancies.
Figure 1. Figure 1. Figure 2. Figure 2.

Disclosures
Locke: Kite Pharma: Other: Scientific Advisory Boards.