Thin-layer chromatography of urinary homovanillic acid and vanillylmandelic acid for large-scale neuroblastoma mass screening

Quebec neonatal mass urinary screening programme: from micromolecules to macromolecules

The Quebec Mass Urinary Screening Programme, initiated in 1971, has resulted in the screening of more than 2,500,000 newborns in the province of Quebec for 25 inherited Mendelian disorders divided into two groups. The first group concerns urea cycle disorders (citrullinaemia, hyperargininaemia, argininosuccinic aciduria), ketotic hyperglycinaemia, and organic acidurias (methylmalonic aciduria, glutaric aciduria type I, etc.); the second group relates to disorders of amino acid metabolism (cystathioninuria, prolidase deficiency, etc.) and transport (Fanconi syndrome, cystinurias, Hartnup syndrome, etc.). The main goal of the Programme is to detect and prevent these genetic diseases, some detectable only in urine, before the onset of clinical symptoms. A multiplex thin-layer chromatography methodology was developed, in which metabolites in urine are resolved and visualized by the sequential application of four different reagents to detect aminoacidopathies and organic acidurias. The technique is simple, reproducible, inexpensive and rapid, allowing the analysis of 500 samples daily by a single technician. The voluntary compliance of the parents is excellent, averaging 90% per year. Over the years, we have established a dynamic process, developing techniques or new reagents to detect as many treatable disorders as possible, now evaluating macromolecules associated with lysosomal storage disorders, mainly globotriaosylceramide (Gb3) for Fabry disease. We present here the methodology, infrastructure in place, results and recent statistics of the well-established Quebec Mass Urinary Screening Programme. We also report a study by tandem mass spectrometric analysis of urinary Gb3 in Fabry disease for the follow-up and monitoring of Fabry patients, as well as for its possible application to mass and high-risk screening programmes.

Treatment Complications in Children Diagnosed With Neuroblastoma During a Screening Program

Purpose

The Québec Neuroblastoma Screening Program was put in place to investigate the possibility of decreasing mortality from high-risk neuroblastoma through early screening. We assess treatment complications in the patients diagnosed during this screening program.

Patients and Methods

A total of 476,603 patients born during the screening period were eligible. Parents of 425,838 children (89%) agreed to participate in the 3-week screening, and 73% agreed to participate in the 6-month screening. Forty-five patients had neuroblastoma. We reviewed the medical and research charts for all patients diagnosed by screening. Follow-up was available from 8 to 13 years after screening.

Results

Forty-five patients were diagnosed by screening. All patients were treated according to the Pediatric Oncology Group recommendations of the time. All patients had surgery, and 29 patients received chemotherapy. No patient died from neuroblastoma. Eleven patients suffered complications from treatment. Two patients had life-threatening complications.

Conclusion

In view of the lack of impact of screening programs on neuroblastoma mortality, evidence that many of the tumors detected through screening can be observed without treatment and the serious complications that may arise from therapy, we do not support neuroblastoma screening programs for children.

Screening for neuroblastoma is ineffective in reducing the incidence of unfavourable advanced stage disease in older children

Neuroblastoma exhibits many characteristics which would suggest that preclinical detection may improve outcome. The Quebec Neuroblastoma Screening Project was initiated to determine whether mass screening could reduce mortality in a large cohort of infants. All 476,603 children born in the province of Quebec during a 5-year period of time (1 May 1989 to 30 April 1994) were eligible for determinations of urinary catecholamine metabolites at 3 weeks and 6 months of age. Children with positive screening were referred to one of four paediatric cancer centres in Quebec for uniform evaluation and treatment. Standardised incidence ratios (SIRs) were calculated for neuroblastoma in Quebec and two comparable population-based controls during the same period of time using similar ascertainment procedures. Compliance with screening in Quebec was 91% at 3 weeks (n = 425,816) and 74% at 6 months (n = 349,706). Up to 31 July 1995 with a follow-up of the birth cohort of 15-75 months, 118 cases of neuroblastoma were diagnosed, 43 detected preclinically by screening, 20 detected clinically prior to screening at 3 weeks of age and 55 detected clinically after 3 weeks of age having normal screens (n = 52) or never screened (n = 3). Based on data from concurrent control populations, 54.5 cases of neuroblastoma would have been expected in Quebec during the study period for an SIR of 2.17 (95% CI 1.79-2.57, P < 0.0001). For the two control groups, the overall SIR was 1.00 (NS). SIRs for Quebec by age at diagnosis in yearly intervals show a marked increased incidence under 1 year of age (SIR = 2.85, 95% CI 2.26-3.50), with no reduction in incidence in subsequent years. We conclude that screening for neuroblastoma markedly increases the incidence in infants without decreasing the incidence of unfavourable advanced stage disease in older children. It is unlikely that screening for neuroblastoma in infants will reduce the mortality of this disease.

A 5-year (1990-1994) neuroblastoma screening feasibility study in France. Methodology and preliminary observations

INTRODUCTION

Following the pioneering Japanese experience, several European and North American groups implemented pilot studies on screening infants for neuroblastoma, considering the possibility of demonstrating a decrease in mortality rate. In France, a 5-year (1990-1994) feasibility study on neuroblastoma screening at the age of 4 months was initiated in the Rhône district (1.5 M inhabitants, 26,000 births per year).

METHODS

Vanillylmandelic (VMA) and homovanillic (HVA) acids were measured by HPLC, and creatinine (Cr) by the Jaffé's kinetic method on Technicon RA-XT. VMA and HVA were expressed as microgram/mg of Cr. The method was assessed with both a daily intra-laboratory control and a sample of urine obtained from a national quality control organism.

RESULTS AND DISCUSSION

The overall participation rate for the 5-year period was 82.2%. Out of 105,293 infants tested from 128,126 births, 12 NB cases were discovered with screening (screened cases) and 1 case was discovered with a late performed test (at 13 months of age). Six neuroblastomas were found clinically before the age of 4 m. Two cases were missed because the parents did not perform the test. Three children with normal tests at screening were false-negative cases: two of them were found secreting at diagnosis, while one remained non-secretory at diagnosis and later on. Otherwise, thirty-five false-positive tests were found. Biochemical observations are discussed. It is too early to reach clinical conclusions from this screening program on neuroblastomas as it is presently being followed up.