Chronic Lymphocytic Leukemia Treatment in México: Up to Half Patients May Not Requiere Treatment

Introduction Chronic lymphocytic leukemia (CLL) is a lymphoid neoplasm which represents the most frequent hematologic malignancy in Caucasians. Every year, there are15,000 new diagnoses and 5000 CLL deaths in the United States. Its prevalence in México and other non-Caucasian populations is substantially lower and the clinical course of CLL patients has been described to be less aggressive Methods All consecutive patients seeking medical care after 1983 in our institution as a result of CLL and followed for at least 3 months were entered in the study. The study was approved by the institutional review board. The treatment of patients was withheld in: (a) Persons with CLL Rai stage 0 or 1, until progression; (b) Persons with CLL Rai stage 2-4, with a negative expression of ZAP-70 until progression. Progression was defined by: Anemia, thrombocytopenia, massive symptomatic or progressive splenomegaly and or adenopathy, progressive lymphocytosis (>50% increase in two months or lymphocyte doubling timeless than 6 months), autoimmune hemolytic anemia not responding to standard therapies, or constitutional symptoms: Weight loss greater than 10% in 6 months, unexplained night sweats or unexplained fever for 2 or more weeks. Refractoriness of the disease was defined as progression despite treatment for a minimum of 3 months. Results Among 98 patients with CLL who were accrued in the study between 1983 and 2019, 49 (50%) were followed for three or more months and accordingly, entered in the study. Median follow up time of the patients is 61 months (95% CI 46.1-75.8). There were 15 females and 34 males, the median age was 65 years (range 23-86). According to the Rai staging system, there were 24 stage 0, 7 stage I, 8 stageII, 0 stage III and 10 stage IV; 80% of patients were identified in stages 0-II. In 28 patients a complete immune phenotype of the malignant cells was analyzed: 89% of patients were ZAP-70 negative (ZAP expression in less than 20% of malignant cells), 79% expressed CD5, 100% CD19 and 86% CD23. Three patients were born in European countries, whereas 6 had an immediate European ancestor, indicating that a Caucasian background was identified in 9/49patients (18%). There were no instances of T-cell CLL. Median OS for all the patients has not been reached, being above 247 months (20 years). The OS of patients given or not any treatment was not statistically different (p= 0.09). It is clear that patients who needed treatment did worse than those not needi