Pb1730: prognostic value of early t-all immunophenotypes in adults on the rall-2016 protocol

Topic: 2. Acute lymphoblastic leukemia - Clinical Background: T-ALL is 25% of all cases of ALL in adults. Since 2017, a new variant of T-ALL – early T-cell precursors (ETP) ALL has been selected. ETP is characterized by its unique immunophenotype (absence of CD1a and CD8 expression, low (<75%) CD5 expression with the obligatory presence of one or more several markers of stem cells or myeloid precursors), by an unfavorable prognosis and a high risk of relapse. Aims: To analyze the survival rate in patients with T-ALL receiving therapy according to the protocol RALL-2016, depending on the variant, as well as to evaluate the effect of the complex karyotype (CK) on the prognosis and risk of relapse. Methods: From December 2016 to June 2022, 94 patients with a diagnosis of T-ALL/lymphoblastic lymphoma were included. Of these, 67 (71%) were male, 37 (39%) were female. Distribution by variants: 19 (20%) - ETP, 8 (8.5%) – near-ETP, 22 (23.5%) – TI/II, 40 (42.5%) – TIII, 5 (5.5%) – TIV. Results: There was no significant difference in median age in all groups, it ranged from 30 (in the ETP) to 37 (in the near-ETP) years. The median of leukocytes was the highest in the TIII (109 × 109/L), and the lowest in the near-ETP (30 × 109/L). The median LDH value was highest in the TIII (2690 IU/L). The number of patients with mediastinal tumors in the group with earlier variants of the disease was lower (in the ETP – 44%, in the TIV – 75%), while they had a neuroleukemia much more often (in the ETP – in 5 patients (26%), in the TIV – was not found). Abnormal karyotype (AK) was most common in the ETP (13 patients – 72%) and TIII (17 patients – 56%) variants of diseases. At the same time, CK was detected only in 2 patients (11%) from TIII. The overall 3-year survival (OS) rate was ETP – 40 %, near-ETP – 71,5%, TI/II – 56%, TIII – 86%, TIV – 60%. The relapse-free survival rate was – ETP - 54%, near-ETP – 33%, TI/II – 79%, TIII – 89%, TIV – 75% (figure 1). OS in the group with AK was 62%, in the group with normal – 80% (p=0.097), in the group with CK was 30%, in the group with any other abnormal – 79% (p=0.00017). Figure 1Summary/Conclusion: ETP is an unfavorable variant of the disease that requires intensification of therapy with the inclusion of allogeneic transplantation in the first remission. Early variants of YALL are characterized by a high recurrence rate during standard chemotherapy. The data received incline to consider patients with near-ETP and CK as candidates for more intensive therapy used in patients with ETP. Keywords: Immunophenotype, T cell acute lymphoblastic leukemia, Acute lymphoblastic leukemia, Acute leukemia