Predictive value of clinical characteristics and baseline ¹⁸F-FDG PET/CT quantization parameters in primary adrenal...

Primary adrenal diffuse large B-cell lymphoma (PA-DLBCL) is a rare occurrence, has a very poor prognosis, and is marked by a high risk of relapse. Accurate prediction of patient prognosis before treatment initiation, along with timely adjustment of the treatment plan, holds paramount importance. 2-Deoxy-2-[fluorine-18]-fluoro-D-glucose (¹⁸F-FDG) positron emission tomography combined with computed tomography (PET/CT) imaging techniques are conventionally performed prior to treatment initiation in DLBCL patients, offering indispensable functional and metabolic insights into lymphoma lesions.

We conducted a retrospective case-control study using data collected from January 2014 to December 2022, including 24 patients diagnosed with PA-DLBCL. Clinical information of patients was collected based on inpatient medical records, including age, gender, B symptoms, adrenocorticotropic hormone (ATCH), lactate dehydrogenase (LDH), β₂-microglobulin, albumin (Alb), ferritin (Fe), blood calcium, Eastern Cooperative Oncology Group performance status (ECOG-PS), International Prognostic Index, Ann Arbor staging, number of involved organs, and Hans' algorithm. Prior to treatment, all patients underwent baseline ¹⁸F-FDG PET/CT, and the metabolic parameters of the tumor were calculated using a threshold of 41% of maximum standardized uptake value (SUVmax), including metabolic tumor volume (MTV) and total lesion glycolysis (TLG). Prognostic analysis of overall survival (OS) was performed using Kaplan-Meier survival analysis, as well as univariate and multifactor Cox proportional hazards regression models.

The 24 enrolled patients comprised 16 men and 8 women (median age 65 years, range 51-90 years). The median follow-up period was 17.5 months (range, 1-107 months). In univariate analysis, Ann Arbor stage, β₂-microglobulin, ATCH, number of involved organs, regions of lymph node involvement, treatment, chemotherapy cycles, SUVmax, MTV, and TLG showed association with OS (P<0.1). In multivariate analysis, Ann Arbor stage, β₂-microglobulin, ATCH, number of involved organs, and treatment were shown to be independent prognostic factors for OS. We found that SUVmax, MTV, and TLG correlated with Ann Arbor staging (P<0.05), mean standardized uptake value (SUVmean) and TLG correlated with the number of involved organs (P<0.05).

PA-DLBCL is characterized by a low incidence and a poor prognosis. Baseline ¹⁸F-FDG PET/CT quantization parameters showed correlations with Ann Arbor staging and number of involved organs. Increasing the sample size or prolonging the follow-up period may reveal the predictive value of PET/CT quantization parameters.