The impact of acute lymphoblastic leukemia treatment on central nervous system results in Bogota, Colombia

A Comprehensive Review of Neuropsychologic Studies Supports the Concept That Adequate Folinic Acid Rescue Prevents Post Methotrexate Neurotoxicity

PURPOSE

To review all studies providing evidence of the correlation between folinic acid (FA) rescue inadequacy and long-term cognitive damage in neuropsychological studies of children with acute lymphoblastic leukemia or osteogenic sarcoma treated under protocols using high-dose methotrexate and FA rescue.

METHODS

A comprehensive literature search was performed of all databases of the Web of Science Citation Index, during 1990-2020, for the terms: neuropsychological, neurocognitive, and cognitive, together with acute lymphoblastic (and lymphocytic) leukemia and osteogenic sarcoma. English-language peer-reviewed articles on neuropsychological assessments of children who had been treated with high-dose methotrexate without irradiation, and which included details of methotrexate and FA schedules, were selected. In addition, a personal database of over 500 reprints of articles from over 130 journals was reviewed on the subjects of methotrexate and FA and their side effects.

RESULTS

Three groups of studies were found and analyzed, with (1) no evidence of cognitive deterioration, (2) evidence of cognitive deterioration, and (3) more than 1 protocol grouped together, preventing separate analysis of any protocols, Protocols without cognitive deterioration reported adequate FA rescue, and those with cognitive deterioration reported inadequate FA rescue.

CONCLUSION

Neuropsychological evaluation supported inadequate FA being the cause of neurocognitive damage after high-dose methotrexate and that adequate FA rescue prevents this complication.

Neurotoxicity after high-dose methotrexate (MTX) is adequately explained by insufficient folinic acid rescue

PURPOSE

To challenge the view that the dose of folinic acid rescue after high-dose methotrexate (MTX) has no significance in the prevention of neurotoxicity and to present the minority view that neurotoxicity can be prevented by an adequate dose of folinic acid, without compromising treatment results. Several fallacies that led to the misunderstanding of post MTX neurotoxicity are presented.

METHODS

Data mining using search engines was used to find relevant publications, and an e-mail survey of more than 60 authors of articles in this field was performed. All relevant articles identified were read in their entirety.

RESULTS

Examples of clinical studies with neurotoxicity following inadequate rescue are given. Some studies demonstrated no neurotoxicity when adequate doses of folinic acid rescue were started 24-36 h after the start of HDMTX rescue even after mega doses of MTX. Rescue started after 42 h was associated with neurotoxicity except in patients with low serum MTX levels after 24 and 36 h. ALL protocols with neurotoxicity, especially BFM-like protocols, are presented. Protocol is reported in which single protocol changes prevented neurotoxicity.

CONCLUSIONS

From the published data, when folinic acid rescue is given in a sufficiently high enough dose and is started 24-36 h after the beginning of the methotrexate exposure, and virtually all forms of post MTX neurotoxicity can be prevented without compromising therapeutic results.

How long can folinic acid rescue be delayed after high-dose methotrexate without toxicity?

To determine the optimal time of folinic acid rescue after methotrexate (MTX) treatment in patients with ALL, we selected and evaluated relevant studies that included doses, rescue delay, and side effects. Rescue at 42-48 hours resulted in considerable toxicity, except when low doses of MTX were used (1 g/m(2)) or serum MTX levels remained consistently low at 24, 30, and 36 hours. Rescue started at 30-36 hours was safe. In the absence of evidence that later rescue improves prognosis, we suggest that folinic acid rescue (105 mg/m(2)) be started no later than 36 hours from the start of MTX (5-6 g/m(2)).

ALL-BFM 95 treatment in Turkish children with acute lymphoblastic leukemia--experience of a single center

Little is known about the likelihood of curing children with high-dose chemotherapy regimens for treatment of childhood acute lymphoblastic leukemia (ALL) in Turkey. The authors here report their 13 years' experience with original ALL-BFM (Berlin-Franfurt-Münster) 95 protocol in a cohort of 140 Turkish children with ALL. Complete remission rate was 97.7% with a relapse rate of 12.9% and death rate 17.9% during a median follow-up of 69 months. The event-free survival (EFS), disease-free survival (DFS), and overall survival (OS) in these patients at 12 years were 75.0%, 87.1%, and 80.6%, respectively. These results show that ALL-BFM 95 protocol is equally applicable in the experienced centers, even in developing countries without substantial treatment-related toxicity. High rate of infection deaths are to be reduced with correct policies.