Outcomes of Infants and Young Children With Relapsed Medulloblastoma After Initial Craniospinal Irradiation-Sparing Approaches: An International Cohort Study

PURPOSE

Infant and young childhood medulloblastoma (iMB) is usually treated without craniospinal irradiation (CSI) to avoid neurocognitive late effects. Unfortunately, many children relapse. The purpose of this study was to assess salvage strategies and prognostic features of patients with iMB who relapse after CSI-sparing therapy.

METHODS

We assembled a large international cohort of 380 patients with relapsed iMB, age younger than 6 years, and initially treated without CSI. Univariable and multivariable Cox models of postrelapse survival (PRS) were conducted for those treated with curative intent using propensity score analyses to account for confounding factors.

RESULTS

The 3-year PRS, for 294 patients treated with curative intent, was 52.4% (95% CI, 46.4 to 58.3) with a median time to relapse from diagnosis of 11 months. Molecular subgrouping was available for 150 patients treated with curative intent, and 3-year PRS for sonic hedgehog (SHH), group 4, and group 3 were 60%, 84%, and 18% (P = .0187), respectively. In multivariable analysis, localized relapse (P = .0073), SHH molecular subgroup (P = .0103), CSI use after relapse (P = .0161), and age ≥ 36 months at initial diagnosis (P = .0494) were associated with improved survival. Most patients (73%) received salvage CSI, and although salvage chemotherapy was not significant in multivariable analysis, its use might be beneficial for a subset of children receiving salvage CSI < 35 Gy (P = .007).

CONCLUSION

A substantial proportion of patients with relapsed iMB are salvaged after initial CSI-sparing approaches. Patients with SHH subgroup, localized relapse, older age at initial diagnosis, and those receiving salvage CSI show improved PRS. Future prospective studies should investigate optimal CSI doses and the role of salvage chemotherapy in this population.

Persistent Child Poverty and Mortality in a Cohort of Children with Cancer in Alabama

BACKGROUND

One-fifth of U.S. counties are designated persistent child poverty counties (≥20% of children in poverty since 1980). The association between a persistent child poverty environment and mortality in children with cancer is unknown.

METHODS

Our cohort includes 2,089 children with cancer (2000-2016) in Alabama. We used multivariable Cox proportional hazards modeling (adjusted for sociodemographics/clinical characteristics) to assess mortality by persistent child poverty designation at 1, 5, and 10 years from diagnosis. Distance to treatment was subsequently explored.

RESULTS

Forty-two percent of the cohort lived in a persistent child poverty county; they were more likely to be African American (P < 0.0001), have public/no insurance (P = 0.0009), and live >100 miles to treatment (P < 0.0001). Children in persistent child poverty counties were 30% more likely to die by 5 years [95% confidence interval (CI) = 1.06-1.59; P = 0.012]. Distance (per 20-mile increase) to treatment was associated with a 9% increased mortality risk (P < 0.0001). Children with both exposures (distance >100 miles and persistent child poverty) faced the highest mortality risk at 5 years (HR = 1.80; 95% CI = 1.39-2.33; P < 0.0001). In subanalysis, children exposed to persistent child poverty were at higher risk for cancer-related mortality. However, the risk of health-related mortality did not differ.

CONCLUSIONS

Among children with cancer from the Deep South, persistent child poverty was a prevalent exposure associated with inferior overall survival. Distance to treatment was independently associated with inferior survival. Children with both exposures had the highest risk of mortality.

IMPACT

Persistent child poverty is associated with inferior survival among children with cancer; mechanisms underlying this disparity warrant investigation. See related commentary by Orjuela-Grimm and Beauchemin, p. 295.

Body mass index during maintenance therapy and relapse risk in children with acute lymphoblastic leukemia: A Children's Oncology Group report

BACKGROUND

Obesity at diagnosis of childhood acute lymphoblastic leukemia (ALL) is associated with greater risk of relapse; whether this association extends to obesity during maintenance is unstudied.

METHODS

This study used data from AALL03N1 to calculate median body mass index (BMI) for 676 children over 6 consecutive months during maintenance therapy; BMI percentile (BMI%ile) were operationalized as normal/underweight (<85%ile), overweight/obese (85%-98%ile), and extreme obesity (≥99%ile). Hazard of relapse was estimated using multivariable proportional subdistributional hazards regression after adjusting for all relevant demographic and clinical predictors.

RESULTS

Median age at study enrollment was 6 years and median length of follow-up was 7.9 years. Overall, 43.3% of the cohort was underweight/normal weight, 44.8% was overweight/obese, and 11.8% had extreme obesity. Cumulative incidence of relapse at 4 years from study enrollment was higher among those with extreme obesity (13.6% ± 4.5%) compared to those with underweight/normal weight (9.0% ± 2.1%). Multivariable analysis revealed that children with extreme obesity had a 2.4-fold (95% confidence interval [CI], 1.1-5.0; p = .01) greater hazard of relapse compared to those who were underweight/normal weight. Overweight/obese patients were at comparable risk to those who were underweight/normal weight (hazard ratio, 0.8; 95% CI, 0.4-1.6). Erythrocyte thioguanine nucleotide (TGN) levels were significantly lower among children with extreme obesity compared to those with underweight/normal weight (141.6 vs. 168.8 pmol/8 × 108 erythrocytes; p = .0002), however, the difference in TGN levels did not explain the greater hazard of relapse among those with extreme obesity.

CONCLUSIONS

Extreme obesity during maintenance therapy is associated with greater hazard of relapse in children with ALL. Underlying mechanisms of this association needs further investigation.

LAY SUMMARY

Findings from this study demonstrate that extreme obesity during maintenance therapy is associated with a greater hazard of relapse among children with acute lymphoblastic leukemia. We show that children with obesity have lower levels of erythrocyte thioguanine nucleotides even after adjusting for adherence to oral chemotherapy. However, these lower levels do not explain the greater hazard of relapse, paving the way for future studies to explore this association.

Individual prediction of nonadherence to oral mercaptopurine in children with acute lymphoblastic leukemia: Results from COG AALL03N1

BACKGROUND

Poor mercaptopurine (6MP) adherence (mean adherence rate < 90%) increases the relapse risk among children with acute lymphoblastic leukemia (ALL). 6MP adherence remains difficult to measure in real time. Easily measured patient-level factors could identify patients at risk for poor adherence.

METHODS

The authors measured 6MP adherence via electronic monitoring for 6 months per patient. Using data from month 3, they created a risk prediction model for 6MP nonadherence in 407 children with ALL (mean age, 7.7 ± 4.4 years); they used receiver operating characteristic analyses in the training set (n = 250) and replicated this in the test set (n = 157).

RESULTS

Age, race/ethnicity, 6MP dose intensity, absolute neutrophil count, 6MP ingestion patterns, and household structure were retained in the prediction model. The model yielded areas under the receiver operating characteristic curve (AUCs) of 0.79 (95% confidence interval [CI], 0.71-0.85) and 0.74 (95% CI, 0.63-0.85) in the training and test sets, respectively. The model performed better for those who were ≥12 years old (AUC, 0.79; 95% CI, 0.59-0.99) than those <12 years old (AUC, 0.70; 95% CI, 0.58-0.81). Using the predicted probability of nonadherence based on receiver operating characteristic analysis, the authors developed a binary risk classifier to classify patients with a high or low probability of nonadherence. The sensitivity and specificity of the binary risk classifier were 71% and 76%, respectively. Adjusted for clinical prognosticators, the risk of relapse was 2.2-fold higher (95% CI, 0.94-5.1; P = .07) among patients with a high probability of nonadherence in comparison with those with a low probability, as identified by the risk prediction model.

CONCLUSIONS

The risk prediction model identified patients with a high probability of nonadherence and could be used in real time to personalize recommendations and interventions in the clinic.

LAY SUMMARY

The vast majority of children with acute lymphoblastic leukemia, the most common childhood cancer, are cured. The treatment of acute lymphoblastic leukemia includes taking an oral chemotherapy medicine (mercaptopurine) for approximately 2 years. Children who miss doses of this medicine (specifically children who take the medicine less than 90% of the time that it is prescribed) are more likely to suffer leukemia relapse. The authors of this article have measured mercaptopurine adherence with electronic bottle caps to determine characteristics of patients that predict nonadherence, and they have created a prediction tool that could allow physicians to identify and intervene with patients at high risk of nonadherence.

MBCL-24. CAN YOUNG CHILDREN WITH RELAPSED MEDULLOBLASTOMA BE SALVAGED AFTER INITIAL IRRADIATION-SPARING APPROACHES?

INTRODUCTION

Irradiation-sparing approaches are used in young children with medulloblastoma (MB) given the vulnerability of the developing brain to neurocognitive impairment. Limited data are available following relapse for these patients. We aimed to describe the management and outcomes of young children with MB who relapsed after initial treatment without craniospinal irradiation (CSI).

METHODS

International retrospective study including patients with MB diagnosed between 1995–2017, ≤ 72 months old, initially treated without CSI, who subsequently relapsed.

RESULTS

Data are available for 52 patients (32 male). Median age at initial diagnosis was 27 months (range, 6–72) with 24 being metastatic. Initial therapy included conventional chemotherapy alone or high-dose chemotherapy (HDC) in 21 and 31 subjects, respectively. Three received upfront focal irradiation. Molecular subgrouping, available for 24 tumors, included 9 SHH and 15 non-WNT/non-SHH. Median time to relapse was 13 months (range, 3–63). Relapse was local, disseminated or combined in 20, 15, and 16, respectively. Salvage therapy with curative intent was given in 42/52 patients, including CSI in 28 subjects (median dose 36Gy, 18–41.4) or focal irradiation in 5 others. Three received HDC only. At a median follow-up time of 46 months (range, 4–255), 25 (48%) were alive, including 7/9 SHH and 7/15 non-WNT/non-SHH. The 2- and 5-year OS was 67% and 56% (SE, 7%), respectively. Two of 3 patients with SHH who did not receive salvage radiotherapy are survivors.

CONCLUSION

A substantial proportion of young children who relapse following irradiation-sparing strategies can be salvaged. Neurocognitive and ototoxicity outcomes are being evaluated.