Side Effects of Adjuvant Therapy in Intermediate- and High-Risk Neuroblastoma
Children with intermediate- or high-risk neuroblastoma receiving multimodal adjuvant therapy face significant acute and long-term toxicities, with high-risk patients—especially those receiving myeloablative therapy—experiencing the most severe complications including hearing impairment, endocrine deficiencies, growth retardation, chronic kidney disease, impaired fertility, cardiotoxicity, neurocognitive impairment, and second malignancies. 1
Risk Stratification of Side Effects
The severity and spectrum of side effects directly correlate with treatment intensity:
High-Risk Disease (Most Severe Toxicity Profile)
Particularly high risk for:
- Hearing impairment (ototoxicity from platinum-based chemotherapy)
- Endocrine deficiencies (thyroid dysfunction, growth hormone deficiency)
- Growth retardation
- Chronic kidney disease
- Impaired fertility (near-universal gonadal insufficiency after busulfan: 40/43 females, 33/35 males) 2
- Cardiotoxicity (from anthracyclines)
- Neurocognitive impairment
- Second malignant neoplasms 1
Intermediate-Risk Disease (Moderate Toxicity Profile)
Patients receive lower cumulative chemotherapy doses and limited/no external beam radiation, resulting in lower risk of long-term toxicities compared to high-risk disease. However, this remains a heterogeneous group with variable chemotherapeutic exposures and still face significant risks for second malignancies and chronic health conditions. 1
Acute Toxicities by Treatment Modality
High-Dose Chemotherapy with Autologous Stem Cell Transplantation
Post-transplant complications include:
- Bloodstream infections (17%)
- ICU admission (20%)
- Respiratory failure requiring intubation (12%)
- Pulmonary hypertension (4%)
- Acute kidney injury (18%, with 5% requiring dialysis)
- Veno-occlusive disease (VOD) (9% post-tandem ASCT)
- Transplant-associated thrombotic microangiopathy (TA-TMA) (16% post-tandem ASCT) 3
Critical pitfall: Endothelial toxicities (VOD and TA-TMA) can prevent progression to tandem transplant and contribute significantly to morbidity and mortality. Early screening and intervention are essential. 3
Anti-GD2 Immunotherapy (Dinutuximab Beta)
Common adverse events:
- Pain (most challenging to manage)
- Fever
- Hypersensitivity reactions
- Capillary leak syndrome
- Hearing loss (13% experience new or worsening hearing loss) 1, 4
These adverse events are considered manageable but require proactive management strategies. 4
Radiation Therapy
Total body irradiation (TBI) significantly impacts:
- Growth hormone deficiency (more severe than non-TBI regimens)
- Bone outcomes (increased skeletal complications)
- Cataracts 5
Contemporary protocols have removed TBI from conditioning regimens due to these significant long-term toxicities, though patients treated without TBI still experience substantial morbidity from high-dose chemotherapy and local radiation. 5
Long-Term Late Effects Profile
73% of survivors have between 5-10 late effects. 5 The most clinically significant include:
Ototoxicity
- Platinum-based chemotherapy causes sensorineural hearing loss
- Critical intervention: Immediate referral to audiology/otolaryngology for impaired hearing to prevent delays in speech/language development, which impacts academic performance and social development 1
Endocrine Dysfunction
- Thyroid disease (11%)
- Growth hormone deficiency (particularly with TBI exposure)
- Gonadal insufficiency (near-universal with busulfan-based regimens) 2
Cardiovascular Toxicity
- Anthracycline-related cardiotoxicity requires echocardiogram monitoring every 2-5 years (if normal at end of therapy) 1
Renal Complications
- Chronic kidney disease (7% in long-term survivors)
- Hepatic focal nodular hyperplasia (14%) 2
Second Malignant Neoplasms
- 11% incidence in long-term survivors
- Median onset: 20 years post-treatment
- Types include: carcinoma (5), sarcoma (2), acute myeloid leukemia (2), melanoma (1), malignant glioma (1)
- Standardized mortality ratio: 19 compared to general population 2
- Risk elevated in both high-risk and intermediate-risk disease 1
Other Significant Late Effects
- Dental maldevelopment (60%)
- Severe hearing loss (20% cumulative probability at 15 years)
- Growth retardation (height-for-age z-score ≤ -2 in 21%) 2
Mortality Impact
Survivors of high-risk neuroblastoma face significantly higher all-cause mortality and grade 3-5 chronic health conditions compared to siblings. The absolute excess risk of death is 37.6 per 1000 person-years compared to the general population. 1, 2
Essential Clinical Management Points
A personalized survivorship care plan must be developed for each patient—generalized recommendations are inappropriate given the heterogeneity of treatment exposures. 1
Fertility preservation referral should occur before chemotherapy initiation when possible for high-risk patients. 1
Monitoring for late effects should begin at each follow-up visit, with formal survivorship follow-up typically starting 2+ years after systemic therapy completion. 1
Consult COG Survivorship Guidelines for comprehensive screening protocols addressing thyroid, cardiac, pulmonary, renal, bone, and reproductive health. 1