APPLICATION of EUTOS SCORE IN CHRONIC Myeloid LEUKEMIA AFFECTING VERY Elderly (>75 years) PATIENTS
Authors: Sica Simona , Breccia Massimo , Autore Francesco , Latagliata Roberto , Abruzzese Elisabetta , Cambrin Giovanna Rege , Gozzini Antonella , Celesti Francesca , Ferrero Dario , Stagno Fabio , Luciano Luigia , Castagnetti Fausto , Annunziata Mario , Cavazzini Francesco , Musto Pellegrino , Pregno Patrizia , Rossi Antonella Russo , Tiribelli Mario , Visani Giuseppe , Rosti Gianantonio , Alimena Giuliana 
Published: October 2019

Abstract
Abstract 1686
The Eutos score has recently been published as a new prognostic score in CML because of its prognostic ability and its simplicity in the imatinib era. It maintains the percent of basophils and the spleen size and it eliminates three other laboratory values and the variable of the age, that is usually important in the prognosis of almost all the diseases. This score was able to predict the probability of achieving a complete cytogenetic response (CCgR) within 18 months, which is the most solid and confirmed surrogate marker of survival in CML treated with imatinib. Thus we reviewed the cases of CML affecting individuals > 75 years and we apply the Eutos score and compare results with classic Sokal risk. We collected 221 patients from 29 of the major Italian hematological centers for diagnosis and treatment of CML. Because of the lack of data for the calculation of the scores in 84 patients, 137 patients were evaluable. The M: F ratio was 70: 67, the median age was of 78 years (range 75–89). Patients aged >75 years as expected showed frequently comorbidities (cardiovascular, respiratory, renal, oncologic ones). The distribution according to the Sokal score was: 3 patients in the low risk group, 95 patients in the intermediate risk group and 39 patients in the high risk group. As expected, there were only few patients in the low Sokal risk group aged >75 years in demonstration of the importance of the age in this score. Calculating Eutos score we have identified only 6 patients with a high score, whereas the remaining 131 patients were in the low risk group. The group with high Eutos risk score included 5 males and 1 female; their median age was 77 years (range 75–78), at the onset their median white blood cell count was 33.840/mmc (range 29.500–300.000), platelet count was 1.443.000/mmc (range 453.000–4.849.000), their median level of hemoglobin was 8.8 g/dl (range 7.7–13.9). All of them showed percent of basophils>12%, whereas at physical examination splenomegaly was usually moderate with no hepatomegaly. Due to the small sample of patients in the high Eutos score statistical analysis was not feasible but we tried to correlate baseline informations to the outcome. Not all the high Eutos risk patients were in the high Sokal risk group (3 patients were in the high Sokal risk group and 3 were in the intermediate one) none was in the low Sokal risk group. All but one patients in the high risk Eutos score were treated with imatinib in early chronic phase of CML. Then we considered the complete cytogenetic response (CCyR) at 18 months, performed through conventional cytogenetic analysis on bone marrow cells by G-banding technique. This has been chosen for the validation of the Eutos score as a solid early surrogate marker of outcome. The overall rate of CCyR was 100% in the low Sokal risk group, 63% in the intermediate Sokal risk group and 69% in the high Sokal risk group; the same type of response was 67% in the low Eutos risk group and 50% in the high Eutos risk group (Table 1). In the high Eutos risk group, 2 patients achieved CCyR, 1 patient achieved MMR, 2 patients did not achieve it and 1 patient was not evaluable. Two patients died because of comorbidities (relapse of colon cancer and cardio-respiratory insufficiency) at 19 and 39 months of follow up. Resistance to imatinib was registered in 17 out of 131 patients (13%) in the low Eutos risk and in 3 out of 6 patients (50%) in the high Eutos risk. In our series of CML patients >75 years, high Eutos score was infrequent (4.38%). Moving from Sokal to Eutos score, patients were largely reallocated as low risk Eutos score. It is not clear whether the low frequency of high risk Eutos might be attributed to a early diagnosis of CML in this subset of patients with age-related comorbidities requiring frequent laboratory exams. In view of the ability to predict CCyR at 18 months, Eutos score validation in the setting of elderly patients with CML could be relevant to clinical practice.Table 1Distribution of patients according Sokal and Eutos scoreN° patients% CCyRSOKALLow risk3100%Intermediate risk9563%High risk3969%EUTOSLow risk13167%High risk650%

Disclosures:
Russo Rossi: Novartis: Honoraria; Bristol Myers Squibb: Honoraria. Rosti:Novartis: Consultancy; Bristol Myers Squibb: Consultancy; Novartis: Research Funding; Novartis: Honoraria; Bristol Myers Squibb: Honoraria.