PS1097 ADULT T‐CELL LEUKEMIA/LYMPHOMA: EPIDEMIOLOGY, CLINICAL FEATURES AND OUTCOME OF A CARIBBEAN COHORT FROM GUADELOUPE
Authors: P. Hélias, W. Lafrance, T. Chalabi, O. Hippomène, D. Clavier, S. Gaumond, M. Saliège, M. Berdou, B. Garin, M. Laruelle, J. Deloumeaux, M. Parrens, V. Baccini
Journal: HemaSphere (2019)

Background: Adult T‐cell leukemia/lymphoma (ATLL) is a rare mature T‐cell malignancy first described in Japan in 1977. The causative agent of ATLL has been identified as the human T cell lymphotropic virus type 1 (HTLV‐1) which is endemic in Japan, Caribbean area, Central and South America and parts of sub‐Saharan Africa. Whereas Japanese cohorts of ATLL are commonly described, the studies gathering ATLL in the Caribbean islands are less frequently provided. ATLL is an unfrequent and subsequently unknown in Europa in opposite to the French overseas departments of the caribbean area. Aims: To report and describe ATLL in the lesser Antilles at the modern area of zidovudine and interferon treatment. Methods: We identified ATLL patients diagnosed in our institution between 2014 and 2018. Charts were reviewed to report clinicopathologic features, treatment patterns and outcomes of this Caribbean cohort exclusively diagnosed in Guadeloupe (French West Indies). ATLL diagnosis is based for all patients on the presence of a clonal T cells proliferation along with positivity for HTLV‐1 serology. Results: Among 309 patients positive for HTLV‐1 in this period, 24 developed an ATLL (7.76%). The median age at presentation is of 59 years (27–92). The sex ratio M/F was 11/13 (0.84). Based on the Shimoyama classification, 14 patients (58,9%) had acute subtype, 9 (37,5%) had lymphomatous and 1 (4,1%) chronic/smoldering disease. 22/24 had lymphadenopathy or deep tumoral syndrom at diagnosis whereas 2 patients presented splenomegaly. LDH was elevated in 23 patients (mean rate is 4.36N (0.94 – 28.03)). Hypercalcemia was present in half of the cases (mean value of 2,69 mg/dL (1.46 – 4.22)). Lymphocytosis was present in 7 patients (29%) and typical flower cells in 14 cases. Circulating lymphocyte phenotyping, performed for 19 patients, showed clonal T‐cells in 15 cases. Two third of the available karyotype were complex with abnormalities of the chromosome 14 in 50% of the cases. Most of the patients (n = 22, 91.6%) received first‐line treatment, whereas 8.3% (n = 2) quickly passed away before initiating any specific medication. As first line, 11 patients were treated by zidovudine and pegylated interferon +/‐ corticosteroid, 10 patients received a polychimiotherapy only or associated with zidovudine and peg‐interferon and one received corticosteroid only. Among the 15 patients with relapse or refractory diseases, 6 were able to receive a second line treatment. One patient benefits from haploidentical bone marrow transplantation. Five patients are still alive at last follow‐up : 3 patients in complete response (including the transplanted patient), 2 in partial response. Among them, 4 are still treated with interferon and zidovudine. Mean overall survival is 10.1 months (0.2–58.4). Among the 18 death with available data: 10 were related to ATLL progression, 6 related to infections and 2 patients died with acute respiratory distress syndrome. Summary/Conclusion: We report the first description of ATLL in Guadeloupe island. Compared to Japanese cohorts, we have younger patients and dominance of acute and lymphomatous ATLL subtypes. Cytologic detection of flower cells needs trained biologists and Shimoyama classification requires a very low blood cell count (&lt;1%) for lymphomatous category. Nevertheless, this detection can be improved by immunophenotyping which might be worthly introduced in this classification. Despite large and early use of zidovudine and interferon, with or without chemotherapy, ATLL remains a very poor prognostic disease confirming that innovative therapies are still needed.