Current urinary mass screening for catecholamine metabolites at 6 months of age may be detecting only a small portion of high-risk neuroblastomas: a chromosome and N-myc amplification study

Screening for neuroblastoma: a review of the evidence

Screening infants for the early detection of neuroblastoma is advocated by many paediatric oncologists and is practised in a limited number of places in the developed world, most notably in Japan where a national screening programme has been in operation since 1985. The screening test consists of measurements of the levels of vanillylmandelic acid and homovanillic acid in the urine; these metabolites of catecholamine are excreted in the urine of 92% of patients with clinically presenting neuroblastoma. The prognosis for children with symptomatic neuroblastoma is dependent both on age and stage, with children aged under 1 year and those with tumours of stages I, II, and IVS having a much better prognosis. Screening aims at detecting and treating during the first year those neuroblastomas which would otherwise present at an advanced stage in older children. Evidence from Japan shows that screening achieves the interim outcomes of a shift in the age distribution and stage distribution of neuroblastomas in populations for whom screening has been provided, and that survival of subjects detected by screening is over 90%, compared with around 50% for symptomatic subjects. However, there is not yet any clear evidence that screening results in a reduction in the incidence of advanced neuroblastoma in children over the age of 1, nor a reduction in mortality. Recent cross sectional analyses of age specific incidence and mortality suggest that screening may be having a limited effect, but as yet no analysis of these outcomes in cohorts for whom screening has been provided has been published. Other factors, such as improved chemotherapy, may also be contributing to lower mortality. A number of missed (interval) cancers have been diagnosed in children who screened negative both in the Japanese programme and in Canadian and English studies, indicating that there is a problem with the sensitivity of screening. But the screening test is highly specific with less than 0.1% of infants having false positive results requiring investigation. The natural history of neuroblastoma ranges from highly malignant tumours to biologically benign variants that regress without active treatment, the prevalence of the latter being inversely related to age. Serial measurements of biological markers, including ploidy, chromosome 1p deletion, and N-myc amplification, performed within the same patient at different times indicate that malignant potential does not progress over time. The distribution of these markers in cases detected by screening shows that they are inherently tumours with a good prognosis, whereas the reverse is true of interval cases. Thus screening is differentially picking up the tumours that are least likely to progress and failing to detect at least some tumours of those destined to die from the disease. Comparison of the yield of cancers detected by screening and the expected cumulative incidence of neuroblastoma throughout childhood suggest that screening "overdiagnoses" many non-progressive cases, with consequent physical and psychological morbidity. On balance present evidence suggests that the number of deaths that could be prevented by screening is small and the potential for overdiagnosis is great. Unless further evidence from Japan or the results of a current North American trial conclude otherwise, screening cannot be recommended.

How to deal with advanced cases of neuroblastoma detected by mass screening: a report from the Pediatric Oncology Study Group of the Kyushu area of Japan

Since 1985, a nationwide program of mass screening (MS) for neuroblastoma has been underway for 6-month-old infants throughout Japan. As a result, the number of patients with stage I or II disease has obviously increased, and this has resulted in overall improvement of the prognosis for neuroblastoma. Some cases detected by MS were already in an advanced stage and have also had a good prognosis. In such cases, no definitive treatment protocol has been developed. Therefore, the authors investigated (1) the clinical and biological features of the advanced neuroblastoma cases detected by MS and (2) the best way to deal with such cases. The authors analyzed 94 cases of advanced-stage neuroblastoma registered in the Kyushu area (population, 15 million) between 1985 and 1990. Eighteen cases (16 stage III, 2 stage IV) were found by MS, and the others (23 stage III, 53 stage IV) were diagnosed clinically. The following results were obtained: (1) No N-myc amplifications were observed in cases detected by MS, whereas 16 of the 45 examined patients in the non-MS group had high amplifications of N-myc. (2) With regard to Shimada's classification, DNA content, and S-100 protein positivity, most of the advanced tumors found by MS showed characteristics indicating a good prognosis. (3) The 5-year survival rate for the non-MS group is less than 25%, whereas all of the patients whose tumors were detected by MS are alive, even after undergoing mild chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

There may be two tumor suppressor genes on chromosome arm 1p closely associated with biologically distinct subtypes of neuroblastoma

We studied loss of heterozygosity (LOH) on chromosome arm 1p in 108 neuroblastomas using 14 polymorphic DNA markers. One-hundred and four tumors with one or more informative loci; 21 (20%) of the 104 tumors showed LOH on 1p, and were classified into three groups on the basis of interstitial or terminal allelic loss, and presence or absence of LOH on 1p. Seven of the 21 tumors showed an interstitial deletion which encompassed a small region in 1p36 (group A), and the other 14 showed a terminal deletion which encompassed the region from 1pter to 1p32 (group B). Eighty-three tumors without LOH on 1p were classified as group C. The group A patients were mostly less than 12 months of age (6/7), were frequently found by a mass screening program for infants (5/7), had a tumor of non-adrenal origin, and rarely progressed to stage IV (1/7). Most group B patients were 12 months or older (11/14), were found clinically (11/14), had tumors of adrenal origin, and progressed to stage IV (10/14). Analysis of biologic characteristics in group C tumors suggested that they may comprise group A and B tumors. While all group A tumors were in the triploid range (3n) (4/4), most group B tumors were diploid (2n) or tetraploid (4n) (7/10). MYCN amplification was found in 8 group B tumors, but in none of group A tumors. Event-free survivals of groups A, B, and C patients at 3 years were 86, 49, and 74%, respectively (P = 0.0287). These findings suggest that there may be two tumor suppressor genes on 1p which are closely associated with two biologically distinct subtypes of neuroblastoma.

DNA flow cytometric analysis of neuroblastoma: distinction of tetraploidy subset

Neuroblastoma has several characteristics that differentiate it from other adult malignancies. The ploidy pattern of neuroblastoma has been shown to be related to prognosis. Specifically, a DNA diploidy pattern is associated with a poorer outcome, and an aneuploidy pattern is associated with a better outcome. A tetraploidy pattern has also been identified; however, there is little information regarding this pattern. To examine the properties of neuroblastoma according to these DNA ploidy patterns, the authors performed flow cytometric analysis (retrospectively) for 61 neuroblastoma cases, using paraffin-embedded tissues. Fifty-six of the cases had analyzable results. Calculated DNA indices (DI) ranged from 1.0 to 2.30. The 56 cases were divided into three groups according to DI: diploid (DI = 1.0 to 1.17, n = 19), aneuploid (DI = 1.25 to 1.75, n = 26), and tetraploid (DI = 1.81 to 2.30, n = 11) groups. Compared with the aneuploid group, the diploid group had a stronger correlation with older patient age (> or = 1 year) (P < .01), more advanced clinical stage (III, IV) (P < .01), and poorer prognosis (P < .001). The tetraploid group had properties that were statistically similar to those of the diploid group (P < .05, P < .05, P < .001, respectively). These findings indicate that a subset of DNA tetraploid is present in neuroblastoma, and this subset, which may have clinical and biological characteristics similar to those of the DNA diploid group, should be distinguished from DNA aneuploidy.

Neuroblastoma with a distinct organoid pattern: a clinicopathologic, immunohistochemical, and ultrastructural study

We studied the organoid pattern in neuroblastoma, defined here as a characteristic histologic feature of the thin fibrovascular meshwork regularly surrounding the individual nests of neuroblastic cells. Among 75 neuroblastomas in our files, 11 cases were qualified as having the recognizable organoid pattern by hematoxylin-eosin stain morphology. The patients comprised five girls and six boys with ages at diagnosis ranging from 1 to 60 months (mean age, 14 months). Nine of the tumors were adrenal and two were retroperitoneal primary. The stages were I (four cases), III (two cases), IV (two cases), and IVS (two cases). All eight patients younger than 1 year are alive and well, whereas two of three patients older than 1 year died of disease. Immunohistochemical staining of those tumors having an organoid pattern showed a considerable number of S-100 protein-positive spindle cells present, mainly in the meshwork areas. Putative Schwann cells were identified ultrastructurally in five of the six tumors examined. In conclusion, organoid pattern in neuroblastoma is easily recognizable, is an indicator of good prognosis in younger children, and may well represent a close relationship between neuroblasts and putative Schwann cells.

Retrospective study of prognostic value of DNA ploidy and proliferative activity in neuroblastoma

AIM

To assess the prognostic value of age and stage at diagnosis, site of primary tumour, cell ploidy and N-myc copy number in children with neuroblastoma.

METHODS

Flow cytometry was used to determine the cellular DNA content of paraffin wax embedded archival material from 69 cases of neuroblastoma and was successful in 52.

RESULTS

The age, stage, and survival distribution of the sampled cases was not significantly different from that in a larger population based series. There were seven diploid ("non-aneuploid") and 45 aneuploid (including two tetraploid and four triploid) tumours. The 10 year survival was significantly better for cases of aneuploid rather than diploid tumours (p < 0.05). An important new finding was that 10 year survival was also significantly better for tumours with a low percentage of cells in S phase (p < 0.03).

CONCLUSION

The percentage of cells in S phase, a measure of the proliferative activity of the tumour, correlated with prognosis in neuroblastoma. This should be measured with other biological features of the disease, such as N-myc copy number, when prognostic indicators are being assessed.

Trends in neuroblastoma in Great Britain: incidence and mortality, 1971-1990

Incidence and mortality rates for neuroblastoma in Britain from 1971 onwards were examined using data from the population-based National Registry of Childhood Tumours. Incidence throughout 1971-1990 was within the range previously reported from Europe, North America and Oceania. The age-standardised rate rose, however, by 26% between 1971-1975 and 1986-1990, and there were increases of 36% both among infants aged under one year and also among children aged 1-9. There was a pattern of increasing risk with more recent years of birth up to 1985. It is implausible that improved diagnosis could explain the increase in rates since 1971, though it may account for a marked decrease in recorded incidence at the age of 10-14. Age-standardised mortality fell by 27% between 1971-1975 and 1981-1985, but rose again during 1986-1990. This was the result of a halt in the improvement in survival rates for neuroblastoma combined with a substantial and as yet unexplained increase in incidence.

MYCN amplification by differential PCR

A method is described to estimate MYCN (N-myc) oncogene amplification in neuroblastoma by the technique of differential polymerase chain reaction (PCR). The technique is quicker than conventional Southern blotting techniques and does not require radioactive materials. The ability to measure MYCN amplification from smaller amounts of tumor DNA also permits measurement from Tru-cut biopsy samples and opens the possibility of retrospective measurement of MYCN status from single paraffin sections of archival material.

Neuroblastoma: a 32-year population-based study--implications for screening

This paper describes a retrospective population-based study of neuroblastoma in the West Midlands Health Authority Region--childhood population 1.12 million (OPCS, census 1981)--in which 239 cases were diagnosed between 1st January 1957 and 31st December 1988. The age standardised rate of tumour incidence has remained constant at 7.2 cases per million children per year. The median age at diagnosis was 2 years with 18% of children presenting before the age of 6 months. Fifty children (21%) presented before the age of one year, and for this group of children, the prognosis has improved significantly over the 32-year period (10 year survival increasing from 63% in 1957-67 to 87% in 1978-88), whereas for the 189 (79%) children who presented after one year of age, the prognosis has remained very poor during the study period (10 year survival 1957-67 = 9.5%, 1978-88 = 8.5%). This study supports the need for a prospective study of mass screening at several intervals rather than only at 6 months of age.