Radiation Therapy for Management of Patients with HTLV-1-associated Adult T-cell Leukemia/Lymphoma

Abstract

Adult T-cell leukemia/lymphoma (ATL) is a rare malignancy associated with chronic infection with human T-cell leukemia virus type 1. It is most often seen in Africa, the Caribbean basin, Southwestern Japan and African-Americans in Southeastern United States. Patients (pts) with acute or lymphomatous type ATL usually have survivals limited to a few months, whereas pts with chronic or smoldering ATL can achieve more prolonged survivals. ATL is typically managed with multi-drug chemotherapy. Only one prior series (Baba et al. 1994), however, has assessed the role of localized radiation therapy (RT) in the management of ATL. This retrospective study examined treatment courses of 10 consecutive pts with pathologically-confirmed ATL treated with RT at the National Institutes of Health from 1997 - 2010. Pts were Afro-Caribbean (9 Jamaican, 1 Haitian), predominantly female (n = 9) and a mean of 48.3 yrs old (range 31 - 65 yrs) at the time of RT. They had acute (n = 7), smoldering (n = 2) or lymphomatous (n = 1) type ATL. They failed an average of 2.5 prior courses of systemic chemotherapies (range 1 - 4) prior to receiving RT at a mean of 12.3 mo (range 5 - 24 mo) after their ATL diagnosis. In total, 17 lesions were treated, all of which were symptomatic. Pts received RT to lymph node masses (9 lesions) or cutaneous (7) or non-cutaneous extranodal (1) disease. Lesions were treated using two-field photon (12) or en face electron (5) RT to a mean dose of 32.2 Gy (range 12 - 60 Gy) in 2.5 Gy fractions (range 2 - 3 Gy). All pts reported symptomatic improvement. At a mean follow-up of 5.1 months (range 0.1 - 18.1 mo), radiographic or clinical response to RT was achieved in all 17 lesions, with partial response in 71% and complete response (CR) in 29% (nodal CR 33% vs. cutaneous CR 29%, p = 0.85). No pt experienced in-field disease progression (0/17 lesions). Four pts developed out-of-field progression, three developed new distant disease and four received multi-drug chemotherapy following RT. Three pts died from disease progression (two deaths within one month of RT completion). Pts experienced RTOG acute grade 1 (n = 1) or grade 2 (n = 2) toxicity. No pt suffered acute grade ≥3 or any RTOG/EORTC late grade ≥1 toxicity. Although multiple subtypes of ATL were evaluated and follow-up was limited due to pt deaths or pts lost to follow-up returning to Jamaica, this study is one of the largest assessing RT to treat or palliate pts with ATL. This study demonstrated that RT can achieve excellent local control and symptomatic improvement across lesion types and ATL subtypes. As ATL is often refractory to systemic therapy, multi-modality therapy is necessary. Radiation therapy in this pt population may be underutilized and should be considered for pts with local disease progression and symptoms.