Survival Rates of Adults With Acute Lymphoblastic Leukemia in a Low-Income Population: A Decade of Experience at a Single Institution in Mexico

Abstract Background The therapeutic progress for adults with acute lymphoblastic leukemia (ALL) has been slow, with a 5-year survival of 30% to 45% in developed countries. Scarce information is available regarding the treatment and survival rates from nonindustrialized populations. In the present study, the characteristics of adults with ALL at a single institution were documented. Patients and Methods The clinical files of patients aged ≥ 18 years who had been diagnosed with ALL from 2005 to 2015 at a reference center in Mexico were scrutinized. Overall survival (OS) and event-free survival (EFS) were determined using the Kaplan-Meier method. The hazard ratios for death and relapse were estimated using Cox regression analysis. Results A total of 94 adults were included. Their median age was 33 years; 69 (73.4%) had high-risk and 25 (26.6%) had standard-risk ALL. Of the 94 patients, 67 (71.3%) achieved complete remission (CR), 20 (21.3%) experienced disease resistance, and 7 (7.4%) died early during induction to remission, mainly of sepsis. The 5-year EFS and OS was 23.4% and 31.1% for the whole group and 24.9% and 38.9% for patients who achieved CR, respectively. Of the 94 patients, 50 (43.9%) died of sepsis or disease progression. Relapse developed in 43 patients (45.7%). The median survival after relapse was 6.93 months. Bone marrow was the most frequent site of relapse (21 patients [48.8%]) and conferred a significantly lower 5-year OS of 16.4%. Conclusion Adults with ALL in Mexico had high-risk characteristics and an increased relapse rate; however, the OS after CR was similar to the greatest achieved in developed countries, suggesting that a threshold for curing adult ALL with current therapeutic strategies has been reached.