Omitting cranial irradiation from the treatment regimen for acute lymphoblastic leukemia (ALL) may help preserve global cognitive abilities. “Treatment with chemotherapy alone is not without risks,” however, noted researchers from St. Jude Children’s Research Hospital in Memphis. “The St. Jude Total Therapy XV study evaluated whether intensification of systemic drugs that affect control of ALL in the central nervous system, together with optimal intrathecal treatment, would allow for complete omission of prophylactic cranial irradiation without compromising overall survival,” the researchers explained. The treatment results “remain excellent with a 10-year overall survival 86.0% for standard/high-risk patients,” but cognitive outcomes had not been systematically investigated or reported.
Cognitive Outcomes Focus of Current Study
For the current study, patients were assessed 120 weeks after completion of consolidation therapy (n = 243).1 “The entire sample performed well on global measures of cognitive ability without evidence of excess impairment on measures of intellectual functioning, academic abilities, and learning and memory,” the researchers wrote. “Problems with sustained attention emerged as the most prominent deficit, with below-average performance in approximately 40% of the sample irrespective of sex, age at treatment, or treatment intensity.”
Compared with patients receiving lower-intensity therapy, those who got higher-intensity chemotherapy were at greater risk for below-average performance as measured by processing speed (27.14% vs 6.25%, P = .009) and academic abilities (math reasoning: 18.60% vs 3.90%, P = .008; word reading: 20.00% vs 2.60%, P = .007; spelling: 27.91% vs 3.90%, P = .001). In addition, higher-intensity chemotherapy was associated with a higher incidence of of parent-reported hyperactivity (23.00% vs 9.84%, P = .018) and learning problems (35.00% vs 16.39%, P = .005).
“These results warrant additional follow-up with potential therapeutic interventions,” according to the authors. They called for caregiver education and interventions to address both early attention deficits and cognitive late effects. ■
1. Conklin HM, et al: Cognitive outcomes following contemporary treatment without cranial irradiation for childhood acute lymphoblastic leukemia. J Natl Cancer Inst 104:1386–1395, 2012.