Persistent positive metaiodobenzylguanidine scans after autologous peripheral blood stem cell transplantation may indicate maturation of stage 4 neuroblastoma

Clinical implication of residual MIBG-positive disease in the follow-up of high-risk neuroblastoma treated with tandem high-dose chemotherapy and autologous stem cell transplantation

BACKGROUND

The implication of residual metaiodobenzylguanidine (MIBG)-positive disease in the era of tandem high-dose chemotherapy (HDCT) with autologous stem cell transplantation (auto-SCT) has not yet been established in neuroblastoma. Moreover, most published studies have not evaluated the long-term prognosis of patients with residual MIBG-positive disease following treatment completion. Therefore, we investigated the prognostic significance of residual MIBG-positive disease at each treatment phase and after treatment completion.

METHODS

We assessed MIBG scans labeled with either iodine-123 (¹²³ I) or ¹³¹ I from 150 patients with MIBG-avid and high-risk neuroblastoma enrolled in the NB-2004, -2009, and -2014 trials at postinduction, posttandem HDCT/auto-SCT, and completion of treatment.

RESULTS

The residual MIBG-positive disease at postinduction and posttandem HDCT/auto-SCT evaluation was highly correlated with the risk of progression. However, at treatment completion, there was no significant difference in survival and risk of progression between patients with residual MIBG-positive disease and MIBG-negative patients. Patients with persistent MIBG-positive disease at the end of treatment were more likely to have indolent tumor characteristics, such as favorable histology at diagnosis, lower incidence of MYCN amplification, and slow response to chemotherapy.

CONCLUSION

Residual MIBG-positive disease during treatment predicted unfavorable outcomes for patients with high-risk neuroblastoma, even under tandem HDCT/auto-SCT. However, persistent MIBG uptake at the completion of all treatments may not always indicate an active disease.

Factors of Recurrence After Complete Response in Children with Neuroblastoma: A 16-Year Retrospective Study of 179 Cases

Background

It is not clear which known adverse prognostic factors of neuroblastoma are closely associated with tumor recurrence after complete response. We analyzed the factors for post-remission recurrence in children with neuroblastoma through a retrospective study.

Methods

A total of 179 children with neuroblastoma who achieved initial complete response were included in this study. Kaplan–Meier method and multivariate Cox regression model were used to assess the factors that may have impact on tumor recurrence after complete response.

Results

The 5-year overall survival rates of the entire cohort (n = 179), recurrence group (n = 86) and non-recurrence group (n = 93) were 81.9%, 66.2%, and 98.7%, respectively. The 5-year recurrence-free survival (RFS) rates of the entire cohort and the high-risk cohort were 47.3% and 31.2%, respectively. RFSs were significantly reduced in children with age ≥18 months, INSS stage 4, unfavorable histology, bone marrow metastasis, osseous metastasis, serum NSE level ≥100 ng/mL, and serum LDH level ≥1400 U/L (P < 0.05). The independent risk factors for post-remission recurrence in the entire cohort were age ≥18 months, unfavorable histology, and serum LDH level ≥1400 U/L (P < 0.05). In the high-risk cohort, the independent risk factor for recurrence was serum LDH ≥1400 U/L (P < 0.05). Based on a new recurrence risk stratification, the 5-year RFSs of the children were 93.5%, 66.4%, and 22.5% in the low-risk, intermediate-risk, and high-risk groups, respectively. The area under the ROC curve of the new stratification was 0.773 (95% CI: 0.704−0.842).

Conclusion

Age ≥18 months, unfavorable histology, and serum LDH level ≥1400 U/L are independent risk factors for post-remission recurrence in children with neuroblastoma. A newly established recurrence risk stratification has diagnostic advantages in predicting risk of recurrence, which is especially suitable for low- and middle-income countries or regions.

Residual meta-iodobenzyl guanidine (MIBG) positivity following therapy for metastatic neuroblastoma: Patient characteristics, imaging, and outcome

BACKGROUND

Meta-iodobenzylguanidine(MIBG) scans are used to detect neuroblastoma metastatic lesions at diagnosis and during posttreatment surveillance. MIBG positivity following induction chemotherapy correlates with poor outcome; however, there are reports of patients with progression-free survival despite MIBG positivity at the end of therapy. The factors distinguishing these survivors from patients who progress or relapse are unclear. FDG-positron-emission tomography (PET) scans can also detect metastatic lesions at diagnosis; however, their role in posttherapy surveillance is less well studied.

METHODS

We performed a retrospective analysis of International Neuroblastoma Staging System (INSS) stage 4 patients to identify those with residual MIBG-avid metastatic lesions on end-of-therapy scans without prior progression. Data collected included age, disease sites, histopathology, biomarkers, treatment, imaging studies, and response.

RESULTS

Eleven of 265 patients met inclusion criteria. At diagnosis three of 11 patients were classified as intermediate and eight of 11 high risk; nine of 11 had documented marrow involvement. Histologic classification was favorable for four of 10 and MYCN amplification was detected in zero of 11 cases. The median time with persistent MIBG positivity following treatment was 1.5 years. Seven patients had at least one PET scan with low or background activity. Biopsies of three of three MIBG-avid residual lesions showed differentiation. All patients remain alive with no disease progression at a median of 4.0 years since end of therapy.

CONCLUSION

Persistently MIBG-avid metastatic lesions in subsets of patients following completion of therapy may not represent active disease that will progress. Further studies are needed to determine whether MYCN status or other biomarkers, and/or PET scans, may help identify patients with residual inactive MIBG lesions who require no further therapy.

Long-term analysis of children with metastatic neuroblastoma treated in the ENSG5 randomised clinical trial

BACKGROUND

The European Neuroblastoma Study Group 5 (ENSG5) trial showed that time-intensive "rapid" induction chemotherapy (COJEC) was superior to "standard" 3-weekly chemotherapy for children with high-risk metastatic neuroblastoma. Long-term outcomes of the ENSG5 trial were analysed.

PROCEDURE

Patients with metastatic neuroblastoma aged ≥12 months were randomly assigned to "standard" or "rapid" induction, receiving the same chemotherapy drugs and doses. Event-free survival (EFS) and overall survival (OS) were analysed and prognostic factors evaluated. Amongst patients surviving >5 years, a population of children with persistent metastatic disease after the end of treatment was identified and described.

RESULTS

Ten-year EFS was 18.2% (95% confidence interval: 12.2-25.2) for the "standard" arm and 26.8% (19.5-34.7) for the "rapid" arm (hazard ratio [HR] 0.85, P = 0.28). Ten-year OS for the "standard" arm was 19.7% (13.4-26.8) and 28.3% (20.8-36.2) for the "rapid arm" (HR 0.83, P = 0.19). There was a trend for worse EFS and OS for patients having MYCN amplification (HR 1.37 and 1.40, respectively) and those with partial and mixed response to induction (HR 1.69 and 1.75 for EFS and 1.66 and 2.00 for OS, respectively). Among 69 patients who survived >5 years, six had persistent metastatic disease after the end of treatment.

CONCLUSION

The benefit of the "rapid" induction regimen seems to be maintained in the long term, although the small number of survivors could justify the lack of statistical significance. MYCN amplification and poor metastatic response to induction could be associated with worse outcomes. A small group of patients with persistent metastatic disease that survived long term has been described.