Medical and Pediatric Oncology 20:84-85 (1992)

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Letter to the Editor: “Decrease in Childhood Neuroblastoma Death in Japan,” Hanawa et al. (1990)

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The pioneering work of the Japanese in the field of neuroblastoma screening has been reported in a series of papers over the past decade. Apparent improvements have been shown in the survival rate of children with neuroblastoma detected by screening. However, for a variety of reasons, including screening picking up cases that might otherwise have remained “silent” and re- gressed spontaneously, length and lead time bias, the only satisfactory way to evaluate a screening programme is to observe changes in mortality rate. Professor Hanawa and colleagues present the first report of neuroblastoma deaths in Japan and show a striking fall in mortality rate from 1984 to 1985 in 1 - to 4-year-old children [ I ] . This coincides with the introduction of screening on a nation- wide basis in Japan in 1985. The paper suggests that the two events may be linked, i.e., that mass screening has resulted in the fall in mortality although the authors do recognise that there may be other reasons for this. We

would like to comment on their paper and produce figures for mortality rate in the United Kingdom, where screen- ing has not been carried out.

The data presented takes no account of screening which was taking place in parts of Japan before 1985. Using the data presented by Takeda [2] on the number of cases identified by screening and population estimates from the Japanese Statistical Year Book 131 it is possible to estimate the proportion of children born in any year who were screened. From the percentage of screened child years amongst all 1- to 4-year-old children in any

Accepted for publication April 18, 1991.

Address reprint requests to Dr. Louise Parker, Children’s Cancer Unit, Department of Child Health, University of Newcastle upon Tyne, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom.

NEUROBLASTOMA : Mortality in Japan 1979 - 1987

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Fig. 1. Neuroblastoma. Mortality in Japan 1979-1987. 0 1992 Wiley-Liss, Inc.

Letter to the Editor 85

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NEUROBLASTOMA : Mortality in Great Britain 1968 - 1987

the steadily increasing survival rate recently reported from the United States [4].

It seems likely that improvements in treatment in Japan, as evidenced by a recent publication from the Japanese Neuroblastoma Study Group, may well be largely responsible for the dramatic fall in mortality from 1984 to 1985. It is unlikely that screening had much part to play as there was only a 3% increase in the proportion of child years screened at the time of this dramatic 4 1 % fall in mortality. In addition despite an increasing pro- portion of the target population screened in 1986 and 1987 the mortality does not change appreciably.

It is clear that it is too early to identify the impact of screening at 6 months of age on mortality in the 1- to 4-year-old group and it will be of paramount importance to continue to observe these important figures from Japan over the next few years.

0 0 Michael Cole, MSC, 6 7 6 9 7 1 7 3 7 5 7 7 7 9 8 1 8 3 8 5 8 7 89 Louise Parker, PhD, and Alan Craft, MD Children’s Cancer Unit Department of Child Health University of Newcastle upon Tyne The Medical School Framlington Place Newcastle upon Tyne, NE2 4HH, United Kingdom

YEAR OF DEATH

Fig. 2. Neuroblastoma. Mortality in Great Britain 1968-1987.

year can be calculated. In 1984, only 2% of the child years at risk of the 1- to 4-year-old population were screened, rising to 5% in 1985, to 18% in 1986, and to 35’ in 1987. These figures are plotted with the mortality rates from the I-hawa Paper in Figure 1 which also includes a correction to the 1987 mortality rate in the 1- to 4-year-olds which was incorrectly shown by Ha- nawa and colleagues.

rate for neuroblastoma in the UK has also fallen as shown in Figure 2. The steady fall is most probably attributable to improvements in treatment as is

REFERENCES

1. Hanawa Y, Sawada T, Tsunoda A: Decrease in childhood neuro- blastoma death in Japan. Med Pediatr Oncol 18:472, 1990.

2. Takeda T: History and current status of neuroblastoma screening in Japan. Med Pediatr Oncol 17:361-363, 1989.

3. Japan Statistical Year Book: Statistics Bureau. Management and Co-ordination Agency, Japan.

4. Seer R: Trends in survival for children under the age 15, selected sites of cancer, 1960-1985 data from the Cancer Statistics Branch, NCI. Ca 40:25, 1990.

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