Treatment of Low-Risk Neuroblastoma
Low-risk neuroblastoma represents nearly one-half of all newly diagnosed patients. The success of prior Children's Oncology Group (COG) clinical trials has contributed to the continued reduction in therapy for select patients with neuroblastoma.
The COG low-risk group assignment criteria are described in Table 6.Table 6. Children’s Oncology Group (COG) Neuroblastoma Low-Risk Group Assignment Schema Used for COG-P9641 and COG-A3961 Studiesa
|INSS Stage||Age||MYCN Status||INPC Classification||DNA Ploidyb|
|≥365 d–21 y||Nonamplified||Any||-|
|≥365 d–21 y||Amplified||Favorable||-|
|INPC = International Neuroblastoma Pathologic Classification; INSS = International Neuroblastoma Staging System.|
|aThe COG-P9641 and COG-A3961 trials established the current standard of care for neuroblastoma patients in terms of risk group assignment and treatment strategies.|
|bDNA Ploidy: DNA Index (DI) > 1 is favorable, = 1 is unfavorable; hypodiploid tumors (with DI < 1) will be treated as a tumor with a DI > 1 (DI < 1 [hypodiploid] to be considered favorable ploidy).|
|cINSS stage 2A/2B symptomatic patients with spinal cord compression, neurologic deficits, or other symptoms are treated with immediate chemotherapy for four cycles.|
|dINSS stage 4S infants with favorable biology and clinical symptoms are treated with immediate chemotherapy until asymptomatic (2–4 cycles). Clinical symptoms include the following: respiratory distress with or without hepatomegaly or cord compression and neurologic deficit or inferior vena cava compression and renal ischemia; or genitourinary obstruction; or gastrointestinal obstruction and vomiting; or coagulopathy with significant clinical hemorrhage unresponsive to replacement therapy.|
(Refer to the Treatment of Stage 4S Neuroblastoma section of this summary for more information about the treatment of stage 4S neuroblastoma.)Standard Treatment Options for Low-Risk Neuroblastoma
For patients with localized disease that appears to be resectable based on the absence of image-defined risk factors (L1), the tumor should be resected by an experienced surgeon. If the biology is confirmed to be favorable, residual disease is not considered a risk factor for relapse. Several studies have shown that patients with favorable biology and residual disease have excellent outcomes with event-free survival (EFS) in excess of 90% and overall survival (OS) of 99% to 100%.[1,2]
Standard treatment options for low-risk neuroblastoma include the following:
- Observation without biopsy (for infants younger than 6 months and disease limited to the adrenal gland that is less than 3 cm in diameter).
- Chemotherapy (for symptomatic disease or unresectable progressive disease after surgery).
Treatment for patients categorized as low risk (refer to Table 6) may be surgery alone, which is curative for most patients with low-risk neuroblastoma. Patients need not undergo complete resection of disease to be cured by surgery alone.
There is controversy about the need to attempt resection, whether at the time of diagnosis or later, in asymptomatic infants aged 12 months or younger with apparent stage 2B and 3 MYCN-nonamplified disease. In a German clinical trial, some of these patients were observed after biopsy or partial resection without chemotherapy or radiation, and many did not progress locally and never received additional resection.Observation without biopsy
Studies suggest that selected small adrenal masses, presumed to be neuroblastoma, detected in infants younger than 6 months by screening or incidental ultrasound may safely be observed without obtaining a definitive histologic diagnosis and without surgical intervention, thus avoiding potential complications of surgery in the newborn.
Evidence (observation without biopsy):
- COG-ANBL00P2 reported that expectant observation is safe, with 81% of patients demonstrating spontaneous regression while avoiding surgical intervention.
- Eighty-three of 87 eligible patients were observed without biopsy or resection and only 16 (19%) ultimately underwent surgery.
- Three-year EFS (for a neuroblastoma event) was 97.7% and OS was 100%.
Results from the COG-P9641 study showed that surgery alone, even without complete resection, can cure nearly all patients with stage 1 neuroblastoma, and the vast majority of patients with asymptomatic, favorable biology, INSS stage 2A and 2B disease. The use of chemotherapy may be restricted to specific situations (e.g., children with MYCN-amplified stage 1 and 2 neuroblastoma and children with MYCN-nonamplified stage 2B neuroblastoma who are older than 18 months or who have unfavorable histology or diploid disease). These children have a less favorable outcome than other low-risk patients.[2,5]
Chemotherapy is also reserved for patients who are symptomatic, such as from spinal cord compression or, in stage 4S, respiratory compromise secondary to hepatic infiltration. The chemotherapy consists of carboplatin, cyclophosphamide, doxorubicin, and etoposide. The cumulative chemotherapy dose of each agent is kept low to minimize permanent injury (COG-P9641).
- The COG-P9641 study was one of the first COG studies to test risk stratification based on consensus-derived factors. In this phase III nonrandomized trial, 915 patients underwent an initial operation to obtain tissue for diagnosis and biology studies and for maximal safe primary tumor resection. Chemotherapy was reserved for patients with, or at risk of, symptomatic disease, with less than 50% tumor resection at diagnosis or with unresectable progressive disease after surgery alone.
- Stage 1: Patients with stage 1 disease achieved 5-year EFS of 93% and 5-year OS of 99%.
- Stage 2A and 2B: Asymptomatic patients with stage 2A and 2B disease (n = 306) who were observed after initial operation had a 5-year EFS of 87% and OS rate of 96%. EFS was significantly better for patients with stage 2A than for patients with 2B neuroblastoma (92% vs. 85%; P = .0321), but OS did not differ significantly (98% and 96%; P = .2867). The primary study objective (to achieve a 3-year OS of 95% for asymptomatic patients with stage 2A and 2B disease) was met. Patients with stage 2B disease had a lower EFS and OS for those with unfavorable histology (EFS, 72%; OS, 86%) or diploid tumors (EFS, 75%; OS, 84%) or for patients older than 18 months. Outcome for patients with stage 2B, diploid tumors, and unfavorable histology was particularly poor (EFS, 54%; OS, 70%), with no survivors in the few patients with additional 1p loss of heterozygosity and all deaths occurring in children older than 18 months.
- Asymptomatic patients at diagnosis who were observed after initial operation: Of the initial 915 patients, 800 were asymptomatic at diagnosis and observed after their initial operations. Within this group, 11% experienced recurrent or progressive disease. Of the 115 patients who received immediate chemotherapy (median, four cycles; range, one to eight), 81% of the patients had a very good partial response or better. After chemotherapy, 10% of the patients had disease recurrence or progression. For patients treated with surgery alone, the 5-year EFS rate was 89% and the overall survival estimate was 97% and for patients treated with surgery and immediate chemotherapy, the 5-year EFS rate was 91% and the overall survival estimate was 98%.
- MYCN amplification: The impact of MYCN-amplified tumors was analyzed in stage I disease. For patients with MYCN-nonamplified tumors the 5-year EFS was 93% and the OS was 99% and for MYCN-amplified tumors the 5-year EFS was 70% (P = .0042) and OS was 80% (P < .001).
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with neuroblastoma. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.
General information about clinical trials is also available from the NCI Web site.References
- Matthay KK, Perez C, Seeger RC, et al.: Successful treatment of stage III neuroblastoma based on prospective biologic staging: a Children's Cancer Group study. J Clin Oncol 16 (4): 1256-64, 1998. [PUBMED Abstract]
- Strother DR, London WB, Schmidt ML, et al.: Outcome after surgery alone or with restricted use of chemotherapy for patients with low-risk neuroblastoma: results of Children's Oncology Group study P9641. J Clin Oncol 30 (15): 1842-8, 2012. [PUBMED Abstract]
- Hero B, Simon T, Spitz R, et al.: Localized infant neuroblastomas often show spontaneous regression: results of the prospective trials NB95-S and NB97. J Clin Oncol 26 (9): 1504-10, 2008. [PUBMED Abstract]
- Nuchtern JG, London WB, Barnewolt CE, et al.: A prospective study of expectant observation as primary therapy for neuroblastoma in young infants: a Children's Oncology Group study. Ann Surg 256 (4): 573-80, 2012. [PUBMED Abstract]
- Bagatell R, Beck-Popovic M, London WB, et al.: Significance of MYCN amplification in international neuroblastoma staging system stage 1 and 2 neuroblastoma: a report from the International Neuroblastoma Risk Group database. J Clin Oncol 27 (3): 365-70, 2009. [PUBMED Abstract]