IBCL-060: Incidence and Survival of Patients with Waldenström Macroglobulinemia Treated at The National Cancer Institute in Peru from 1999 to 2018

Abstract

Context Waldenstrom macroglobulinemia (WM) is a lymphoplasmacytic lymphoma (LPL) with a monoclonal immunoglobulin M. In Latin America, only two articles have been published, the first was of a Mexican population accounting for 0.18% of Hematological Malignancies (HM), and the second study was of Chileans. The incidence of WM in the Caucasian population according to the literature is 2% of HM. Objective To describe the incidence, clinical pathological characteristics, and survival of WM. Design Retrospective case series from 1999–2018. Setting National Cancer Institute in Peru. Patients All patients with diagnosis of WM (ICD-10 C880) and LPL (ICD-O 9671/3) to reclassify as WM if appropriate. Interventions RCHOP. Main Outcomes Measures Baseline characteristics (BCL), response rates, and survival; the latter was used in the Kaplan-Meier method for analysis. Results Thirteen patients with newly diagnosed WM were found during the study period. From 1999 to 2018, 24.744 patients were treated at the NCI. The incidence of WM was 0.052%, 38 times less frequent than in the Caucasian population. Eight patients had complete medical records and were evaluated for BCL and survival. However, the entire cohort had information for age and sex. The median age was 63 (range 24–76), and 62% (n=8) were male. B-symptoms were present in 50% of cases. Anemia was reported in 87.5% and thrombocytopenia in 38%. Fifty percent had B2 microglobulin >3 mg/dL, and 88% of patients had a high International Prognostic Scoring System for WM (IPSSWM). The most frequent front-line treatment was CVP with 38%, followed by R-CHOP and CHOP with 25% and 13%, respectively. No complete response was reported, and 88% achieved partial response. With a median follow-up time of 16 months, the median progression-free survival (PFS) time was 14 months. The 1-year PFS was 64.3% (95% CI, 15.2–90.2), and the 2-year PFS was 21.4% (95% CI, 8.9–60.5). The median overall survival (OS) time was not achieved. The 3- and 5-year OS was 71.4% (95% CI, 25.8–91.9). Conclusions WM is an extremely rare HM in the Peruvian population, 38 times less frequent than in Caucasians. Most patients have a high IPSSWM score. Although most patients did not use Rituximab, the OS was good considering the high IPSSWM score.