Early mortality and contemporary survival in intravascular large B-cell lymphoma: A population-based SEER study.

Abstract

e19089 Background: Intravascular large B-cell lymphoma (IVLBCL) is a rare and aggressive extranodal lymphoma that frequently presents with nonspecific symptoms, often leading to delayed diagnosis and poor outcomes. Prior population-based SEER analyses described survival through 2013; however, outcomes in the modern treatment era and prognosis among longer-term survivors remain incompletely characterized. We evaluated contemporary survival, early mortality, temporal patterns, and clinical presentation in a national cohort. Methods: We conducted a retrospective study of adults with IVLBCL in SEER (17 registries, 2000–2022) using ICD-O-3 histology code 9712/3. Demographic and clinical variables, including age, sex, stage, and receipt of systemic therapy per the SEER chemotherapy recode, were collected. Cutaneous phenotype was defined as primary skin involvement. Early mortality was assessed at 30 and 90 days. Overall survival was estimated using Kaplan–Meier methods. Survival was compared by diagnosis era (2000–2013 vs 2014–2022). Conditional survival was calculated at 12- and 24-month landmarks. Results: A total of 123 patients were included. Median age was 66 years, and 46% were male. Sixty-five percent received systemic therapy, and 16% had localized disease at diagnosis. Early mortality was substantial, with 30- and 90-day mortality rates of 29% and 32%. Median overall survival was 22 months, with 1- and 2-year survival of 56% and 49%. Survival appeared longer in the contemporary era (median 35 vs 17 months). Conditional 1-year survival was 88% among patients alive at 12 months and 95% among those alive at 24 months. Cutaneous-limited disease represented 6% of cases and showed longer survival, although estimates were exploratory, and cutaneous presentations may be undercaptured in SEER. Conclusions: IVLBCL remains associated with substantial early mortality despite modern therapy. Outcomes appear more favorable in recent years, and patients who survive the first 1–2 years have an improved subsequent prognosis. These findings provide contemporary population-level benchmarks to guide counseling and risk stratification and should be interpreted in the context of potential registry misclassification and coding limitations. Patient characteristics and outcomes in IVLBCL (SEER 2000 to 2022). Characteristic Value Patients, n 123 Median age, years 66 Male sex, % 46 Received systemic therapy, % 65 Localized stage at diagnosis, % 16 30-day mortality, % 29 90-day mortality, % 32 Median overall survival, months 22 Conditional 1 year survival among 12-month survivors, % 88 OS, overall survival. Systemic therapy includes chemotherapy or chemoimmunotherapy per SEER coding.