Epidemiology, clinical features, and outcome of HTLV-1-related ATLL in an area of prevalence in the United States

Adult T-cell leukemia/lymphoma (ATLL) is a fatal disease caused by human T-cell leukemia virus type 1 (HTLV-1). We retrospectively analyzed 195 patients with ATLL (lymphomatous n = 96, acute n = 80, unfavorable chronic n = 7, chronic n = 5, smoldering n = 3, and unclassified n = 4) diagnosed between 1987 and 2016 (median age 52 years, 77% Afro-Caribbean). Hypercalcemia was associated with acute ATLL (65%, vs 23% lymphomatous) (P = .012). The median survival for patients treated with modern therapies between 2000 and 2016 was 4.1 months for acute, 10.2 months for lymphomatous, 72 months for chronic/smoldering, and not reached for unfavorable chronic type, with 4-year survival rates of 10%, 4%, 60%, and 83%, respectively. The overall response rate (ORR) after first-line multiagent chemotherapy was 78% (complete response [CR] 39%) for acute vs 67% (CR 33%) for lymphomatous ATLL. First-line zidovudine interferon-α (AZT-IFN) resulted in ORR of 56% (CR 23%) for acute (n = 43), 33% (CR 16.5%) for lymphomatous (n = 6), and 86% (CR 29%) for unfavorable chronic ATLL. The median progression-free survival (PFS) in patients with aggressive ATLL who achieved CR after AZT-IFN was 48 months vs 11 months after chemotherapy (P = .003). Allogeneic hematopoietic stem cell transplant (allo-HSCT) resulted in a PFS of 24 and 28 months in 2 patients with lymphomatous ATLL. Our results suggest high-dose AZT-IFN is a reasonable up-front option for patients with aggressive leukemic ATLL followed by chemotherapy switch in nonresponders, whereas chemotherapy should be used in lymphomatous type followed by allo-HSCT when feasible.