Evidence for an age cutoff greater than 365 days for neuroblastoma risk group stratification in the Children's Oncology Group.

PURPOSE: In the Children's Oncology Group, risk group assignment for neuroblastoma is critical for therapeutic decisions, and patients are stratified by International Neuroblastoma Staging System stage, MYCN status, ploidy, Shimada histopathology, and diagnosis age. Age less than 365 days has been associated with favorable outcome, but recent studies suggest that older age cutoff may improve prognostic precision. METHODS: To identify the optimal age cutoff, we retrospectively analyzed data from the Pediatric Oncology Group biology study 9047 and Children's Cancer Group studies 321p1-p4, 3881, 3891, and B973 on 3,666 patients (1986 to 2001) with documented ages and follow-up data. Twenty-seven separate analyses, one for each different age cutoff (adjusting for MYCN and stage), tested age influence on outcome. The cutoff that maximized outcome difference between younger and older patients was selected. RESULTS: Thirty-seven percent of patients were younger than 365 days, and 64% were > or = 365 days old (4-year event-free survival [EFS] rate +/- SE: 83% +/- 1% [n = 1,339] and 45% +/- 1% [n = 2,327], respectively; P < .0001). Graphical analyses revealed the continuous nature of the prognostic contribution of age to outcome. The optimal 460-day cutoff we selected maximized the outcome difference between younger and older patients. Forty-three percent were younger than 460 days, and 57% were > or = 460 days old (4-year EFS rate +/- SE: 82% +/- 1% [n = 1,589] and 42% +/- 1% [n = 2,077], respectively; P < .0001). Using a 460-day cutoff (assuming stage 4, MYCN-amplified patients remain high-risk), 5% of patients (365 to 460 days: 4-year EFS 92% +/- 3%; n = 135) fell into a lower risk group. CONCLUSION: The prognostic contribution of age to outcome is continuous in nature. Within clinically relevant risk stratification, statistical support exists for an age cutoff of 460 days.

Detection of MYCN gene amplification in neuroblastoma by fluorescence in situ hybridization: a pediatric oncology group study.

To assess the utility of fluorescence in situ hybridization (FISH) for analysis of MYCN gene amplification in neuroblastoma, we compared this assay with Southern blot analysis using tumor specimens collected from 232 patients with presenting characteristics typical of this disease. The FISH technique identified MYCN amplification in 47 cases, compared with 39 by Southern blotting, thus increasing the total number of positive cases by 21%. The major cause of discordancy was a low fraction of tumor cells (< or =30% replacement) in clinical specimens, which prevented an accurate estimate of MYCN copy number by Southern blotting. With FISH, by contrast, it was possible to analyze multiple interphase nuclei of tumor cells, regardless of the proportion of normal peripheral blood, bone marrow, or stromal cells in clinical samples. Thus, FISH could be performed accurately with very small numbers of tumor cells from touch preparations of needle biopsies. Moreover, this procedure allowed us to discern the heterogeneous pattern of MYCN amplification that is characteristic of neuroblastoma. We conclude that FISH improves the detection of MYCN gene amplification in childhood neuroblastomas in a clinical setting, thus facilitating therapeutic decisions based on the presence or absence of this prognostically important biologic marker.

Residential pesticide exposure and neuroblastoma.

Neuroblastoma is the most common neoplasm in children under 1 year of age. We examined the relation between residential exposure to pesticides and neuroblastoma, using data from a case-control study of risk factors for neuroblastoma. Incident cases of neuroblastoma (N = 538) were identified through the Pediatric Oncology Group and the Children's Cancer Group. One age-matched control was identified for each case by random digit dialing. Telephone interviews with each parent collected information on residential exposure to pesticides. Pesticide use in both the home and garden were modestly associated with neuroblastoma [odds ratio (OR) = 1.6 (95% confidence interval [95% CI] = 1.0-2.3, and OR = 1.7 (95% CI = 0.9-2.1), respectively]. Compared with infants [OR = 1.0 (95% CI = 0.6-2.0)], stronger associations were found for garden pesticides in children diagnosed after 1 year of age [OR = 2.2 (95% CI = 1.3-3.6)], which suggests that pesticides may act through a mechanism more common for neuroblastomas in older children. There was no evidence of differential pesticide effects in subgroups of neuroblastoma defined by MYCN oncogene amplification or tumor stage.

Natural history and biology of stage A neuroblastoma: a Pediatric Oncology Group Study.

PURPOSE: To prospectively analyze the outcome of patients with Stage A neuroblastoma (NB) treated with surgery alone, especially with regard to the prognostic significance of age, tumor site, MYCN copy number, tumor cell ploidy, and histology. PATIENTS AND METHODS: The clinical course of 329 patients with Stage A disease registered on the POG NB Biology Study #9047 between February, 1990 and October, 1997 were evaluated. Age, tumor site, MYCN copy number, tumor cell ploidy, and histology were analyzed for their impact on event-free survival (EFS) and survival (S). RESULTS: The 5-year estimated EFS and S rates for the 329 patients were 91% (+/-3%) and 96% (+/-2%), respectively. The EFS rate was similar for infants younger than 12 months and children age 12 months or older, but age older than 12 months was predictive of lower S rates (P = 0.044). Patients with adrenal, abdominal non-adrenal, thoracic, and cervical tumors had similar S rates. The majority of patients had tumors with favorable biologic features, and only 3% had MYCN amplification. For infants with diploid tumors, the EFS rate was 82% (+/-16%), but effective therapy yielded an S rate of 100%. Rate of S was 80% (+/-26%) and 64% (+/-27%) for patients with unfavorable tumor histology and MYCN-amplified tumors, respectively. CONCLUSION: The outcome for patients with Stage A NB treated with surgery alone is excellent. Although EFS and S rates were significantly worse for patients with MYCN-amplified tumors, a subset achieved long-term remission after surgery alone. For patients with Stage A and MYCN amplification, additional factors are needed to distinguish the patients who will achieve long-term remission with surgery alone from those who will develop recurrent disease.

Genetic analysis of childhood endodermal sinus tumors by comparative genomic hybridization.

Childhood endodermal sinus tumors (CEST) are a distinct category of germ cell tumors that involve the testis and extragonadal sites of young children. Recurrent deletions of 1p and 6q have been reported by classic cytogenetic analysis of a small number of cases. Comparative genomic hybridization, a technique that screens the entire genome for genetic abnormalities, is applied to additionally define the genetic changes present in CESTs. Sixteen frozen CESTs (10 testicular, 6 extragonadal) obtained from Pediatric Oncology Group-affiliated institutions or from the Cooperative Human Tissue Network were analyzed. The most common changes were gain of 20q (10 tumors), 1q (6 tumors), 11q and 22 (4 tumors each), and loss of 6q (8 tumors with common deleted region of 6q24-qter), 16q (4 tumors), and 1p (4 tumors). Localized regions of gain were identified at 8q24 (2 tumors both showing c-myc amplification by fluorescence in situ hybridization). Gain of 12p, characteristic of adolescent germ cell tumor, was present in one testicular tumor. Comparative genomic hybridization was useful in defining genetic differences between adult and childhood tumors, in determining the common regions deleted on chromosome 6, and in identifying other involved loci to be correlated with clinical parameters in future studies.

Inhibition of juvenile myelomonocytic leukemia cell growth in vitro by farnesyltransferase inhibitors.

Juvenile myelomonocytic leukemia (JMML) is an early childhood disease for which there is no effective therapy. Therapy with 13-cis retinoic acid or low-dose chemotherapy can induce some responses, but neither mode is curative. Stem cell transplantation can produce lasting remissions but is hampered by high rates of relapse. The pathogenesis of JMML involves deregulated cytokine signal transduction through the Ras signaling pathway, with resultant selective hypersensitivity of JMML cells to granulocyte-macrophage colony-stimulating factor (GM-CSF). A JMML mouse model, achieved through homozygous deletion of the neurofibromatosis gene, confirmed the involvement of deregulated Ras in JMML pathogenesis. With this pathogenetic knowledge, mechanism-based treatments are now being developed and tested. Ras is critically dependent on a prenylation reaction for its signal transduction abilities. Farnesyltransferase inhibitors are compounds that were developed specifically to block the prenylation of Ras. Two of these compounds, L-739,749 and L-744, 832, were tested for their ability to inhibit spontaneous JMML granulocyte-macrophage colony growth. Within a dose range of 1 to 10 micromol/L, each compound demonstrated dose-dependent inhibition of JMML colony growth. An age-matched patient with a different disease and GM-CSF-stimulated normal adult marrow cells also demonstrated dose-dependent inhibitory effects on colony growth, but they were far less sensitive to these compounds than JMML hematopoietic progenitors. Even if the addition of L-739,749 were delayed for 5 days, significant inhibitory effects would still show in JMML cultures. These results demonstrate that a putative Ras-blocking compound can have significant growth inhibitory effects in vitro, perhaps indicating a potential treatment for JMML. (Blood. 2000;95:639-645)

Complete surgical excision is effective treatment for children with immature teratomas with or without malignant elements: A Pediatric Oncology Group/Children's Cancer Group Intergroup Study.

PURPOSE: To determine whether the 3-year event-free survival (EFS) of children with completely resected immature teratomas is greater than 85%. PATIENTS AND METHODS: Patients with immature teratomas treated at Pediatric Oncology Group or Children's Cancer Group institutions were eligible. Pathology was centrally reviewed to confirm diagnosis and tumor grading. Follow-up included physical examination, measurement of tumor markers (alpha fetoprotein and human chorionic gonadotropin), and imaging. All patients were monitored for events, defined as tumor recurrence, second malignancy, or death. RESULTS: Seventy-three children (median age, 7.8 years) with extracranial immature teratomas were enrolled on study. Primary tumor sites included ovarian (n = 44), testicular (n = 7), and extragonadal (n = 22). However, on review, 23 patients had foci of yolk sac tumor (n = 21) or primitive neuroectodermal tumor (n = 2), whereas 50 had pure immature teratomas. Twenty-five patients had increased alpha fetoprotein (n = 18), human chorionic gonadotropin (n = 5), or both (n = 2); nine had foci of yolk sac tumor on review. Pathology review identified 23 patients with grade 1, 29 with grade 2, and 21 with grade 3 immature teratomas. With a median follow-up of 35 months, the overall 3-year EFS was 93% (95% confidence interval, 86% to 98%), with 3-year EFS of 97.8%, 100%, and 80% for patients with ovarian, testicular, and extragonadal tumors, respectively. Only four of 23 patients with immature teratoma and malignant foci developed recurrence, suggesting that surgical resection followed by close observation are effective treatment. Overall, five patients had disease recurrence 4 to 7 months from diagnosis, and four (80%) are disease free after platinum-based therapy. The fifth patient has residual tumor after cisplatin, etoposide, and bleomycin treatment requiring further therapy. CONCLUSION: Surgical excision is safe and effective treatment for 80% to 100% of children with immature teratoma.

Hormone and fertility drug use and the risk of neuroblastoma: a report from the Children's Cancer Group and the Pediatric Oncology Group.

Previous epidemiologic studies have suggested an association between maternal sex hormone use during pregnancy, including infertility medication, and an increased risk of neuroblastoma in the offspring. The authors conducted a case-control interview study from 1992 to 1996 that included 504 children less than 19 years of age whose newly diagnosed neuroblastoma was identified by two national collaborative clinical trials groups in the United States and Canada, the Children's Cancer Group and the Pediatric Oncology Group. Controls, matched to cases on age, were identified by random digit dialing. No association was found for use of oral contraceptives before or during pregnancy (first trimester odds ratio (OR) = 1.0, 95% confidence interval (CI): 0.5, 2.1). The odds ratio was slightly elevated for history of infertility (OR = 1.4, 95% CI: 0.9, 2.1) and ever use of any infertility medication (OR = 1.2, 95% CI: 0.7, 2.2). Specifically, ever use of clomiphene was associated with a 1.6-fold increased risk (95% CI: 0.8, 3.0) but not periconceptionally or during the index pregnancy. A suggestive pattern was found for gender of the offspring, with an increased risk for males but not for females after exposure to oral contraceptives or clomiphene. This study did not find consistent and large increased risks for maternal use of hormones, but the suggestion of an association for male offspring requires further consideration.

Surgical resection alone is effective treatment for ovarian immature teratoma in children and adolescents: a report of the pediatric oncology group and the children's cancer group.

OBJECTIVE: In both adult women and children the potential for malignant recurrence from ovarian immature teratoma has prompted the standard use of chemotherapy after complete resection of the primary tumor. The efficacy of postoperative chemotherapy in children and adolescents with ovarian immature teratoma, however, has not been established. A pediatric intergroup trial (INT 0106) was designed to determine the need for postoperative chemotherapy in patients with ovarian immature teratoma after management with surgical resection only. STUDY DESIGN: Between 1990 and 1995, 44 patients with completely resected ovarian immature tumor and without postoperative chemotherapy, who were able to undergo assessment, were accrued. Tumor tissue was evaluated by central pathology review to confirm diagnosis and determine tumor grading of immature neural elements. Patients were followed carefully for recurrence of disease with appropriate diagnostic imaging and serum marker studies. RESULTS: Thirty-one patients had pure ovarian immature teratoma with a tumor grade of 1 (n = 17), 2 (n = 12), or 3 (n = 2). Age at diagnosis ranged between 1.5 and 15 years (median, 10). Of the 29 patients studied, the serum alpha-fetoprotein level was elevated in 10 (34%); the median level was 25 ng/ml. Thirteen patients had ovarian immature teratoma plus microscopic foci of yolk sac tumor. Tumor grade was 1, 2, or 3 in 1, 6, and 6 patients, respectively. Age ranged between 6 and 20 years (median, 12). In the 12 patients evaluated for serum alpha-fetoprotein, 10 (83%) had elevated levels; the median level was 262 ng/ml. The 4-year event-free and overall survival for the ovarian immature teratoma group and for the ovarian immature teratoma plus yolk sac tumor group was 97.7% (95% confidence interval, 84.9%-99.7%) and 100%, respectively. The only yolk sac tumor relapse occurred in a child with ovarian immature teratoma and yolk sac tumor who was then treated with chemotherapy and is alive and free of disease 57 months after recurrence. CONCLUSION: The results of this study suggest that surgery alone is curative for most children and adolescents with resected ovarian immature teratoma of any grade, even when elevated levels of serum alpha-fetoprotein or microscopic foci of yolk sac tumor are present. This experience strongly supports avoiding the long-term effects of chemotherapy in most children with ovarian immature teratoma by reserving postoperative therapy for cases with relapse.

The International Neuroblastoma Pathology Classification (the Shimada system).

BACKGROUND: The International Neuroblastoma Pathology Committee, which is comprised of six member pathologists, was convened with the objective of proposing a prognostically significant and biologically relevant classification based on morphologic features of neuroblastic tumors (NTs) (i.e., neuroblastoma, ganglioneuroblastoma, and ganglioneuroma). METHODS: A total of 227 cases were reviewed. Consensus diagnoses from morphologic features (criteria described separately) based on five of six or six of six agreements by the reviewer pathologists were used for prognostic analysis. Prognostic effects of morphology, both individual and in combination, taken in conjunction with age (Shimada classification, histologic grade, and risk group), were analyzed. RESULTS: Approximately 99% of cases (224 of 227) had consensus diagnoses for categorization: neuroblastoma (Schwannian stroma-poor), 190 cases; ganglioneuroblastoma, intermixed (Schwannian stroma-rich), 5 cases; ganglioneuroma (Schwannian stroma-dominant) maturing, 1 case; ganglioneuroblastoma, nodular (composite Schwannian stroma-rich/stroma-dominant and stroma-poor), 19 cases; and NT-unclassifiable, 9 cases. For the NTs, subtype (93% consensus: undifferentiated, 6 cases; poorly differentiated, 155 cases; and differentiated, 15 cases), mitosis-karyorrhexis index (90% consensus: low, 94 cases; intermediate, 40 cases; and high, 37 cases), mitotic rate (75% consensus: low, 89 cases; high, 50 cases; and not determined, 4 cases), and calcification (100% consensus: yes, 110 cases and no, 80 cases) were recorded. Statistical analysis demonstrated that the Shimada classification system (90% consensus; 3-year event free survival: 85% for the group with favorable histology and 41% for the group with unfavorable histology; P = 0.31 x 10(-9)) had a significantly stronger prognostic effect than individual features and other combinations. CONCLUSIONS: The International Neuroblastoma Pathology Classification, a system based on a framework of the Shimada classification with minor modifications, is proposed for international use in assessing NTs.

Lymph node sampling in localized neuroblastoma: a Pediatric Oncology Group study.

BACKGROUND/PURPOSE: Lymph node (LN) sampling was required by the Pediatric Oncology Group (POG) staging for neuroblastoma and currently is required as a part of the International Neuroblastoma Staging System (INSS). This retrospective study of planned lymph node sampling in patients with localized neuroblastoma was carried out with the intent of assisting surgeons in carrying out this procedure. The report documents the POG experience where LN, both uninvolved and involved with tumor, were found based on site of primary. METHODS: From 391 patients with localized neuroblastoma of the abdomen, chest, and neck, 238 patients had LN sampling at the primary operation, and these patients constitute the major part of the study. In addition, 89 patients had a carefully documented search for LN, and 64 had neither search nor biopsy. The operative note, pathology report, and surgical study sheet were used in the 238 patients based on the site of the primary tumor to determine which nodal groups or basins underwent biopsy, and in which groups tumor was found. RESULTS: The pattern of drainage, based on the primary site of abdominal tumors, favored an arterial rather than venous pathway. Primary tumors and metastatic LN were more numerous on the left side. The abdominal drainage followed three pathways: (1) infrarenal tumors from the left and midline were associated with paraaortic LN; (2) right infrarenal tumors were associated with LN in the paracaval basin; (3) with suprarenal primaries and with both adrenals, the superior mesenteric-portal-celiac basins were most productive for nodal sampling. Tumor was found most frequently in the left adrenal-renal basin and in the paraaortic basin. The actual number of LN sampled in a single case varied from 1 to 19 LN, with a mean number of LN based on stage and primary from one to seven LN. The tumor spread in LN was consistent with a "watershed" course, but this was not statistically significant. Patients for whom LN were sought had a better outcome, contrasting with the patients in whom LN were not sought or in whom nodal sampling was not possible. CONCLUSIONS: The experience in this study is consistent with previous descriptions of the lymphatic drainage of the retroperitoneal area. Delineation of the various basins as they relate to the site of the primary tumor should assist the surgeon in lymph node sampling. The role of LN involvement still remains unclear in the light of current studies of biological factors and histopathology as determinants of "risk groups." It is hoped that this study will enable ongoing and future studies to clarify this problem. The adult experience with breast cancer and with melanoma has indicated a continued importance of anatomic factors (including LN status) along with biological factors.

Neuroblastoma and parental occupation.

OBJECTIVES: We evaluated parental occupation and the risk of neuroblastoma using data from a large case-control study conducted by the Children's Cancer Group and the Pediatric Oncology Group. METHODS: We compared the distribution of 73 paternal and 57 maternal occupational groups among 504 newly diagnosed cases of neuroblastoma and individually matched controls obtained by telephone random digit dialing in the United States and Canada. RESULTS: An increased risk of neuroblastoma was found for fathers employed as broadcast, telephone and dispatch operators (odds ratio [OR] = 6.1; 95% confidence interval [CI] = 0.7-50.9), electrical power installers and power plant operators (OR = 2.7; CI = 0.9-8.1), landscapers and groundskeepers (OR = 2.3; CI = 1.0-5.2), and painters (OR = 2.1; CI = 0.9-4.8). Elevated odds ratios were found for mothers employed as farmers and farm workers (OR = 2.2; CI = 0.6-8.8), florists and garden store workers (OR = 2.4; CI = 0.6-9.9), hairdressers and barbers (OR = 2.8; CI = 1.2-6.3), electric power installers and power plant operators, and sailors, fishers, and railroad workers. No increase in risk was found for other paternal occupations previously associated, including electricians, electrical equipment assemblers and repairers (OR = 1.1; CI = 0.6-2.0), or welders (OR = 0.5; CI = 0.1-1.6). CONCLUSION: The study reinforced some prior evidence of increased risks in electrical, farming and gardening, and painting occupations, but failed to confirm other previously reported associations. Further analyses of exposure to electromagnetic fields, metals, solvents, and pesticides are currently under way.

Mutations of the NF1 gene in children with juvenile myelomonocytic leukemia without clinical evidence of neurofibromatosis, type 1.

Juvenile myelomonocytic leukemia (JMML) is a pediatric myelodysplastic syndrome that is associated with neurofibromatosis, type 1 (NF1). The NF1 tumor suppressor gene encodes neurofibromin, which regulates the growth of immature myeloid cells by accelerating guanosine triphosphate hydrolysis on Ras proteins. The purpose of this study was to determine if the NF1 gene was involved in the pathogenesis of JMML in children without a clinical diagnosis of NF1. An in vitro transcription and translation system was used to screen JMML marrows from 20 children for NF1 mutations that resulted in a truncated protein. Single-stranded conformational polymorphism analysis was used to detect RAS point mutations in these samples. We confirmed mutations of NF1 in three leukemias, one of which also showed loss of the normal NF1 allele. An NF1 mutation was detected in normal tissue from the only patient tested and this suggests that JMML may be the presenting feature of NF1 in some children. Activating RAS mutations were found in four patients; as expected, none of these samples harbored NF1 mutations. Because 10% to 14% of children with JMML have a clinical diagnosis of NF1, these data are consistent with the existence of NF1 mutations in approximately 30% of JMML cases.

Prognostic significance of age, MYCN oncogene amplification, tumor cell ploidy, and histology in 110 infants with stage D(S) neuroblastoma: the pediatric oncology group experience--a pediatric oncology group study.

PURPOSE: Although a high rate of spontaneous regression is observed in infants with stage D(S) neuroblastoma (NB), survival is not uniform. To determine the prognostic relevance of age at diagnosis, therapy, and tumor biology in infants with stage D(S) NB, we reviewed the Pediatric Oncology Group (POG) experience. PATIENTS AND METHODS: A review of patients diagnosed with stage D(S) NB registered on POG protocols was performed. Survival according to age at diagnosis, treatment, and tumor biology was determined. RESULTS: Between 1987 and 1996, 110 infants with stage D(S) NB had an estimated 3-year survival rate of 85% +/- 4%; survival rate was 71% +/- 8% for infants 2 months of age or younger, and 68% +/- 12%, 44% +/- 33%, and 33% +/- 19% for patients with diploid, MYCN-amplified, and unfavorable histology tumors, respectively. Survival rates were similar for patients who received adjuvant chemotherapy versus those who did not (82% +/- 5% v 93% +/- 6%, respectively; P = .187). Furthermore, there was no statistical difference in survival rate for patients who underwent complete resection of their primary tumor compared with those who underwent partial resection or biopsy only (90% +/- 5% v 78% +/- 7%, respectively; P = .083). CONCLUSION: Our review confirmed that the survival of infants with stage D(S) NB is excellent. However, subsets of patients with poor prognosis can be identified by young age and unfavorable biologic factors. More effective therapy is needed for the group of stage D(S) infants who show unfavorable clinical and biologic features.

The risk of nephrectomy during local control in abdominal neuroblastoma.

METHODS: Eight hundred sixty-eight children presenting from 1981 to 1991 were treated on five multiagent chemotherapy protocols by members of the Pediatric Oncology Group for advanced-stage neuroblastoma with large primary tumors crossing the midline or distant metastasis. Of these children, 696 had abdominal (adrenal or paravertebral) primary tumors. One hundred sixteen children underwent greater than 50% surgical resection of these abdominal primary tumors before chemotherapy, and 233 underwent similar surgery after induction chemotherapy. RESULTS: Among the 349 who underwent surgical resection, 52 children (14.9%) had nephrectomy or renal infarction during surgery for local control. There was a 25% incidence among those with initial resection (29 patients) and a 9.9% incidence in the postchemotherapy resections (23 patients). Reasons for nephrectomy given by the surgeons included direct involvement of the kidney by adjacent tumor (17 children), clinical impression that the tumor was a Wilms' tumor (11 children), renal vessels could not be separated from the tumor (10 children), extensive tumor surrounding the kidney (8 children), postoperative renal infarction (4 children), marked decrease in unilateral renal function after chemotherapy (1 child), and position of the tumor posterior to the kidney and vena cava making resection without nephrectomy impossible (1 child). Of the patients undergoing nephrectomy, four children had an upper pole nephrectomy in conjunction with their adrenalectomy and resection of the tumor. Pathological review of the resected tumor available in 47 cases demonstrated direct involvement of the renal parenchyma in 18 cases (38% of the nephrectomies) and in 5.2% of those undergoing resection. In children undergoing initial resection, the risk for nephrectomy (as calculated by the methods described by Gart) was more than twice compared with those undergoing resection after chemotherapy (P = .012; odds ratio, 2.32; 95% confidence interval of 1.23 to 4.42). CONCLUSIONS: This review confirms that renal parenchymal involvement does occur in a significant number of children with abdominal neuroblastoma. It also suggests that preoperative chemotherapy may decrease the number of nephrectomies required to achieve a total or subtotal resection.

Biology and treatment of neuroblastoma.

Neuroblastoma is an enigmatic tumor that has the highest rate of spontaneous regression of all human malignant neoplasms, yet has one of the poorest outcomes when occurring as disseminated disease in children. The emergence of neuroblastoma tumor biology, coupled with age and stage of diagnosis, has allowed more accurate routing of patients to risk-related therapy and refining of such therapy to minimize treatment for those with low risk for recurrent disease and searching out new treatment strategies for patients with high-risk disease. Continued assessment of tumor biologic features in all patients will provide new insights into tumorigenesis, cell differentiation, and death pathways, resulting in the potential for developing newer therapies for patients with high-risk disease.

Neuroblastoma.

The neuroblastic tumours, derived from primordial neural crest cells which ultimately populate the sympathetic ganglia, adrenal medulla and other sites, (Brodeur GM and Castleberry RP. Neuroblastoma. In Pizzo PA, Poplack DG, eds, Principles and Practice of Pediatric Oncology. Philadelphia, J. B. Lippincott Co., 1997, 761-797) are an enigmatic group of neoplasms which have the highest rate of spontaneous regression of all human malignant neoplasms yet one of the poorest outcomes when occurring as disseminated disease in children. Significant advances in understanding and predicting the natural history of neuroblastoma have resulted from translational studies coupling tumour biology and clinical features to form prognostic strata and allowing more accurate routeing of patients to risk-related management. While this strategy has clarified the management for lower risk tumours, little improvement in survival for higher risk disease has been realised. Ironically, this latter patient subset, for which the most innovative therapeutic strategies are needed, is also the one from which the least tumour biology is gleaned owing to inadequate tissue sampling. This update will summarise the evolving biology of neuroblastoma and its relationship to current risk-related therapy and future management strategies. Throughout this report, prognostic grouping by age will be infants (< 1 year) versus children (> or = 1 year) since the change of risk according to age seems most distinct at this cut-off point.

Genetic staging of unresectable or metastatic neuroblastoma in infants: a Pediatric Oncology Group study.

BACKGROUND: Current staging systems for unresectable or metastatic neuroblastoma do not reliably predict responses to chemotherapy in infants under 1 year of age. Previous studies have indicated that the DNA content, or ploidy, of malignant neuroblasts can discriminate between good and poor responders in this group of patients, but the clinical utility of ploidy assessment has remained in question. PURPOSE: We tested, in a prospective nonrandomized study, the hypothesis that neuroblast ploidy could be used as the sole guide for treatment selection in infants with unresectable or metastatic tumors and could differentiate between those who would respond to our previous standard regimen and those who would benefit from an immediate switch to another therapy. METHODS: One hundred seventy-seven infants were enrolled in this trial. Five of these infants were subsequently excluded (two ineligible, two lacking ploidy information, and one protocol violation); therefore, 172 patients were included in the study. One hundred thirty infants with hyperdiploid tumors (DNA index > 1.0; better prognosis in retrospective studies) were treated with a well-tolerated regimen of cyclophosphamide (150 mg/m2 per day orally or intravenously on days 1-7) and doxorubicin (35 mg/m2 intravenously on day 8). Forty-two infants with diploid tumors (DNA index = 1.0; worse prognosis in retrospective studies) received cisplatin (90 mg/m2 intravenously on day 1) and teniposide (100 mg/ m2 intravenously on day 3) after an initial course of cyclophosphamide plus doxorubicin. Statistical end points were response and long-term survival. In addition, we assessed within each ploidy group (i.e., patients with hyperdiploid tumors and those with diploid tumors) the prognostic significance of NMYC gene copy number, tumor stage, and other variables commonly measured in this disease. RESULTS: Of the 127 assessable infants with hyperdiploid tumors, 115 (91%) had complete responses--85 after receiving five courses of cyclophosphamide plus doxorubicin and 30 after receiving further therapy including cisplatin plus teniposide. The 3-year survival estimate for the entire hyperdiploid group was 94% (95% confidence interval [CI] = 89%-98%). Nineteen (46%) of 41 assessable infants with diploid tumors were complete responders. The overall 3-year survival estimate for this group was 55% (95% CI = 39%-70%). Prognostic factor analysis indicated that NMYC gene amplification and an elevated serum lactate dehydrogenase level were statistically significant markers of higher risk disease within the diploid group (two-sided P values of .005 and .003, respectively). Only NMYC was predictive in the hyperdiploid group (P = .003). CONCLUSION: Use of a prognostic staging system based on tumor cell ploidy, augmented with the NMYC gene copy number and serum level of lactate dehydrogenase, would very likely improve the treatment of infants with unresectable or metastatic neuroblastoma. Patients with diploid tumors characterized by an amplified NMYC locus represent a particularly unfavorable risk group that may benefit from innovative new therapies.