Neuroblastomas in Denmark 1943-80. Epidemiological and clinical studies

The epidemiology of neuroblastoma: a review

Neuroblastoma is the most common tumour in children less than 1 year of age. The goal of this review was to summarise the existing epidemiological research on risk factors for neuroblastoma. A comprehensive search of the literature was undertaken using PubMed for epidemiological studies on neuroblastoma risk factors. We ascertained 47 articles which examined the risk factors. Ten studies employed population-based case-control designs; six were hospital-based case-control studies; two were cohort studies; and five employed ecological designs. Studies ranged in size from 42 to 538 cases. Three studies showed evidence of an increased risk of disease with use of alcohol during pregnancy (OR range 1.1, 12.0). Protective effects were seen with maternal vitamin intake during pregnancy (OR range 0.5, 0.7) in two studies, while risk of disease increased with maternal intake of diuretics (OR range 1.2, 5.8) in three studies. Three studies reported a decrease in risk for children with a history of allergic disease prior to neuroblastoma diagnosis (OR range 0.2, 0.4). The rarity of neuroblastoma makes this disease particularly challenging to study epidemiologically. We review the methodological limitations of prior research and make suggestions for further areas of study.

Unchanged incidence and increased survival in children with neuroblastoma in Denmark 1981-2000: a population-based study

Treatment results for neuroblastoma in Denmark have been poorer than in other Nordic countries, so we investigated whether a change in incidence, stage distribution and survival had occurred between 1981 and 2000. Clinical data were retrieved from the medical charts of 160 children <15 years of age with extra-cranial neuroblastoma (n=139) or ganglioneuroblastoma (n=21) diagnosed in Denmark between 1981 and 2000. The minimal follow-up time was 52 months. Statistical analyses were performed in STATA. The incidence was 8.55 per million children below 15 years of age (world standard 9.6) and 42.6 per million children below 12 months of age, and it has remained unchanged since 1970. The median age at diagnosis was 27 months. In all, 32% of the children were aged below 12 months at diagnosis, 53% had metastatic disease and in 12% the diagnosis was made incidentally. Prognostic factors such as age, stage and site of primary tumour were the same as in other studies and did not change. During the study period, the mortality rate decreased steadily, and the 5-year survival rate increased from 38% in 1981–1985 to 59% in 1996–2000, corresponding to the level found in other Western countries. Increased survival was also seen in children with metastatic disease. Participation in international studies, better supportive care and possibly postoperative autologous stem cell transplantation may have contributed to the increased survival.

High-risk neuroblastoma in Ontario: a report of experience from 1989 to 1995

PURPOSE

We did a population-based study of children with high-risk neuroblastoma to determine their survival and look for factors that had an impact on survival.

METHODS

We carried out a retrospective cohort study of patients diagnosed in Ontario from 1989 to 1995. 162 cases of neuroblastoma were diagnosed in the province with 70 (43%) considered high-risk: all were older than one year of age, with 15 patients classified as International Neuroblastoma Staging System (INSS) stage 3, and 55 INSS stage 4.

RESULTS

Stage 3 patients did significantly better than Stage 4 patients with a 5-year overall survival of 67.7% and 22.7% respectively (P = 0.015). In stage 4 patients achieving at least a partial response to up-front therapy and surviving for at least 9.5 months after diagnosis (the median time to transplant), there was no difference in survival between the 19 transplant patients and the 17 treated with chemotherapy alone (P = 0.75). However, patients transplanted by peripheral stem cell (PSC) collection did significantly better than both the bone marrow transplantation (P = 0.002) and chemotherapy-alone group (P = 0.047). There was a significant difference in up-front chemotherapy and use of radiation in the three groups (P < 0.001 and P = 0.01 respectively), but no difference in the incidence of bone and bone marrow metastases, MYCN amplification or unfavorable histology.

CONCLUSIONS

In this nonrandomized study, we found that stage 4 neuroblastoma patients alive more than 9.5 months after diagnosis, with at least a partial response to initial therapy, did significantly better with PSC transplant compared with bone marrow transplantation or chemotherapy alone.

Prognostic discrimination among neuroblastomas according to Ha-ras/trk A gene expression: a comparison of the profiles of neuroblastomas detected clinically and those detected through mass screening

BACKGROUND

Neuroblastomas (NBs) exhibit a wide variety of clinical behavior. It is important to determine the biology of NB before treatment is instituted.

METHODS

One hundred six NBs detected clinically (clinical NBs) were classified according to immunohistochemical expression of the Ha-ras and trk A genes. Association of the two-gene expression with patient outcome was examined retrospectively, and the possibility of prognostic prediction was evaluated. The profile of the expression of the two genes in 85 NBs detected through mass screening (mass NBs) was compared with that in clinical NBs.

RESULTS

Ha-rasltrk A expression in clinical NBs was associated with disease free survival, even when the NBs had no amplification of the N-myc gene. Multivariate analysis demonstrated that the expression of Ha-rasl/trk A was a significant prognostic factor that was independent of stage, age at diagnosis, and N-myc amplification. Favorable outcomes of patients with advanced NB were distinguished by high Ha-ras and high trk A expression, and unfavorable outcomes were distinguished by low Ha-ras and low trk A expression. A profile of the two genes in mass NBs was different from that in clinical NBs. Greater than 50% of the mass NBs were detected as localized tumors with high Ha-ras and high trk A expression. The mass screening detected NBs with favorable and unfavorable biology.

CONCLUSIONS

The expression of Ha-ras and trk A is an excellent predictor of both favorable and unfavorable biology in NBs. The information it provides can be important in determining the appropriate therapeutic intervention for each patient.

Prenatal exposure to metronidazole and risk of childhood cancer: a retrospective cohort study of children younger than 5 years

BACKGROUND

To evaluate the role of in utero exposure to metronidazole (a carcinogen in some animal models) and the risk of subsequent cancer, the authors conducted a retrospective cohort study of childhood cancer.

METHODS

The cohort included 328,846 children younger than 5 years born to women enrolled in Tennessee Medicaid at any time between the last menstrual period (LMP) and the date of delivery. The cohort was identified by linking files of Tennessee Medicaid mothers ages 15-44 years and children and the children's birth and death certificates for the period January 1, 1975 through December 31, 1992. Exposure data were obtained from Medicaid pharmacy records and exposure was defined as filling a metronidazole prescription that had at least a day's supply between the 30 days prior to the LMP and the date of delivery. Study cases were cohort children diagnosed with a first primary cancer before age 5 years, identified by linking the cohort with a statewide childhood cancer database for the study period.

RESULTS

Cohort members contributed 1,172,696 person-years of follow-up for analysis, with children exposed (8.1%) and not exposed (91.9%) in utero to metronidazole contributing 79,716 and 1,092,980 person-years, respectively. Of 952 children younger than 5 years in the statewide cancer database, 175 met study eligibility criteria. Of these, 42 had leukemia, 30 had central nervous system (CNS) tumors, 28 had neuroblastoma, and 75 had other cancers. Using Poisson regression modeling, children exposed to metronidazole in utero had no significant increase in adjusted relative risk (RR) for all cancers (RR: 0.81; 95% confidence interval [95% CI], 0.41-1.59), leukemia (no exposed case), CNS tumors (RR: 1.23; 95% CI, 0.29-5.21), neuroblastomas (RR: 2.60; 95% CI, 0.89-7.59), and other cancers (RR: 0.57; 95% CI, 0.18-1.82).

CONCLUSIONS

The authors conclude that although there was no increase in risk for all cancers associated with in utero exposure to metronidazole, the observed increased risk for neuroblastomas, although not significant, requires further evaluation.

Trends of survival in neuroblastoma and independent risk factors for survival at a single institution

To assess the progress of survival in neuroblastoma which varies with many risk factors and to evaluate the influence of these factors on survival as independent risk factors. The study subjects were 159 neuroblastoma patients seen from 1965-1994 at the oldest and largest children's hospital in Japan. Trends of survival in three treatment eras-1965-81, 1982-86, 1987-94-were assessed by the Kaplan-Meier method for different sex, age at diagnosis, the clinical stage, the site of onset, and the histological type. Then the influence on survival of these factors as independent prognostic variables was evaluated by the Cox proportional hazards regression analysis. Age at diagnosis, the clinical stage, the site of onset, the histological type, and the treatment era were independent risk factors in the order of their influence on survival. Unfavorable survival outcomes were obtained for patients with age at diagnosis above 1 year, the clinical stage of VI by the Evans classification, adrenal onset, and neuroblastoma rather than ganglioneuroblastoma. Survival improved from the first to the second and from the second to the third treatment era. Improvement of survival in neuroblastoma took place during the past 3 decades. Age at diagnosis, the clinical stage, and the histological type have still remained overwhelming prognostic factors over the progress in treatment.

The recurrence patterns of stages I, II and III neuroblastoma: experience with 77 relapsing patients

BACKGROUND

Recurrences of neuroblastoma Evans' stage I-III are infrequent events and the types of its progression have rarely been reported. Therefore, we investigated the patterns of progression in a large series of patients with long follow-up.

PATIENTS AND METHODS

The sites of relapse and time to progression and death of 381 consecutive patients in three cooperative trials (NB 79, 82, 85) with follow-up of 5-16 years were analysed. The Southern blot technique was used for N-myc investigation of tumor tissue.

RESULTS

Of the 77 relapsing patients, 41 (53%) had local and 36 (47%) systemic recurrences. The relapses occurred in 9 of 76 stage I patients (6 local/3 systemic), in 4 of 82 stage II (1 local/3 systemic) and 64 of 223 stage III neuroblastoma (34 local/30 systemic) patients. The main sites of distant metastasis were bone marrow (41%), lymph nodes (39%) and bone (37%). The median transition time from localised to metastatic neuroblastoma was 13 months and the outcome as poor (overall survival 9 +/- 5%) as that of the primary metastatic disease (14 +/- 3%). Fifty-three children died of tumor progression and 15 patients of treatment-related complications or other non-tumor conditions. The median age at diagnosis was 43 months for the group with systemic relapse compared to 19 months with only local and 10 months without recurrences (p < 0.001). Elevated serum LDH levels at first diagnosis were seen in 81% with metastatic, in 55% with local and in 33% with no tumor progression (p < 0.001). N-myc amplification was found in 4/14 with local and in 6/12 with metastatic recurrences.

CONCLUSION

The high incidence of systemic relapse and the long transition time suggest that transition from localised to metastatic neuroblastoma is not an uncommon pathway.