Introduction

Chemotherapy treatments in the pediatric population have shown high survival rates (80% to 90%) in Acute lymphoblastic leukemia (ALL), but in adolescents and young adults, success has been significantly lower, with survival rates of 30% to 40%. it has been proposed that in the AYA population (15 to 45 years of age), the effective chemotherapy regimens used in the pediatric population should be modified in dose and frequency.

Methodology

A historical cohort study was conducted from the patient registry of the Adult Hematology Service of a referral hospital. Patients between the ages of 15 and 45, with phenotype B, who received first-line treatment with modified pediatric chemotherapy regimens were selected. Most patients received the LALÍN institutional regimen, which consists of 5 induction medications applied as follows: daunorubicin 120 mg / m2 for 48 hours on days 0 and 1, cyclophosphamide 1200 mg / m2 on day 2, vincristine 1.4 mg / m2 weekly for 4 weeks, prednisone 60 mg / m2 on day 2 to day 23. Philadelphia-positive patients were managed with dasatinib and negative patients with L-asparaginase 4,000 IU / m2, 3 times a week until consolidation, followed by intensification with cytarabine 1.5 g / m2 for 8 doses, consolidation with methotrexate 1 g / m2 and vincristine, and then early and subsequent maintenance.

Results

A descriptive, cross-sectional, observational, and retrospective study was conducted from 2017 to 2023, targeting the AYA population. 143 records were analyzed, of which only 98 met the full criteria. 55.1% were men and 44.9% were women. The age range was 17 to under 34 years, 67.3%, and 32.6% were 35 or older, with a mean of 29.3 years.

Weight and body mass index, it was found that 1% were underweight, 40% were normal weight, 36.7% were overweight, and 21.4% were obese.

It was observed that the majority of patients presented with grade II and III anemia (35.7% and 28.5%, respectively), 27.5% with grade I anemia, and only 8% did not present any anemia at diagnosis.

The risk associated with the leukocyte count at diagnosis, 68.3% had leukocyte counts below 30,000. 80.5% presented some degree of thrombocytopenia, with severe thrombocytopenia occurring in 50% of patients at diagnosis. 72.4% presented elevated lactate dehydrogenase. 47.9% did not present any type of organomegaly.

45.9% had a normal karyotype, 63% had a negative translocation panel, and 75% had a negative RT-PCR for BCR ABL::ABL. 23.4% were Philadelphia chromosome positive, primarily associated with the p190 breakpoint, and 18.3% had a complex karyotype. 57.2% were morphologically classified as L2 according to the Fab classification, and only 33.3% had CNS infiltration at diagnosis.

Within the risk group, 74.4% of patients were at high risk.

Regarding post-induction response assessment, the median time for evaluation was 33 days. Complete response was achieved in 93.8% of patients, induction failure occurred in 9.8%, and response assessment was not possible in 17.3% due to death during induction or undocumented outcomes.

Regarding MRD measurement, the median time was 35 days. MRD was documented in 81 patients; 48.1% (39) were positive post-induction, and 51.8% (42) were negative.

The median survival rate for deceased patients was 47 months, while for those still alive, it was 66 months.

Among the variables associated with overall survival, the only one that presented statistical significance was the presence of negative MRD after induction, as a predictor of good prognosis. With a p < 0.011. 37.7% were still alive at the time of study analysis.

Only 19 patients did not experience any events, with a median survival rate of 70 months.

Univariate analysis showed no significant differences in sex, presence of the Philadelphia chromosome, risk status at diagnosis, morphology, or weight.

Conclusions

Patients treated with protocols inspired by pediatric regimens demonstrated a higher complete remission rate compared to traditional intensive adult regimens.

Our institutional LALÍN regimen demonstrated induction response rates greater than 90%, with a 3-year overall survival rate of 32.5% and a survival rate of 44 months during the evaluation period. Therefore, our institutional regimen represents a good therapeutic option for patients in the AYA population, combined with immunotherapy management and transplantation in patients who relapse.

key word: Acute lymphoblastic leukemia, adolescents and young adults, Overall survival

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2025
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