Acta Pzdiatr Scand 67: 425432, 1978
CHILDHOOD CANCER IN SWEDEN. 1958-1974 I. Incidence and mortality J. L.-E. ERICSSON, L. KARNSTROM and BRITTA MATTSSON From the Central Laboratory for Clinical Pathology, University Hospital, University of Uppsala, Uppsala, and Stockholm-Gotland Oncologic Centre, Karolinska Hospital, Stockholm, Sweden
ABSTRACT. Ericsson, J. L.-E., Karnstrom, L. and Mattsson, B. (Central Laboratory for Clinical Pathology, University of Uppsala, Uppsala, and the Stockholm-Gotland Oncologic Centre, Karolinska Hospital, Stockholm, Sweden). Childhood Cancer in Sweden, 1958-1974. I. Incidence and Mortality. Acta Paediatr Scand, 67: 425, 1978.-All cases of tumours and tumour-like conditions in children &14 years reported to the Swedish cancer registry during the period 1958-74 have been studied. The material consists of 3 797 individuals on file in this registry. The most common cancer diagnoses in children &14 years are leukemia and tumours of the central nervous system (together constituting approximately 58 % of all cases). Almost half of the cancers affect children below five years of age. The lowest incidence occurs in the ages 7-8 years, and the highest during the first year of life. The types of tumours below one year of age show a different distribution than in other age groups. A significant increase in the incidence of childhood cancer occurred, while the mortality rates showed a slight decrease during the period studied. A remarkable increase in the incidence figures was noted concerning tumours of the nervous system, especially in boys. The decrease in the mortality rates was most obvious regarding Wilms’ tumour, and leukemia in children 0-4 years of age. KEY WORDS: Childhood cancer, incidence, mortality
Recent evidence stresses the importance of the epidemiologic approach to the study of etiologic factors in the causation of cancer in adults as well as in children. Earlier studies from the Swedish cancer registry have revealed a significant increase in the incidence of malignant tumours since the start of the national registration of incidence of cancer in 1958 (1, 11). Thus, the overall mean annual increases have been 2.3% for males and 1.5% for females, while the mortality rates-as revealed by mortality statisticshave been decreasing slightly over recent decades, with a decrease of 0.4% annually for males and 0.7 % for females. Great variability in the incidence trends of different types of tumours has been noted in Sweden. For instance, primary cancer of the liver has shown an increase of approximately 7 % per year, while cancer of the stomach has decreased by about 2.5 % annually. These re-
sults concern the population as a whole. Knowing that the pattern of cancer diagnoses in childhood differs very much from that in adults , no conclusions concerning childhood cancers can be drawn from the aforementioned studies. It is the purpose of this paper to supply data concerning the incidence and mortality of childhood cancer in Sweden since the inception of the national cancer registry, with special reference to analyses of changes of the rates (trend patterns). MATERIAL AND METHODS All cases of tumours and tumour-like conditions in children 0-14 years reported to the Swedish cancer registry during the period 1958-74 have been studied. The material consists of 3 797 individuals on file in this registry. In addition to histologically clearly malignant tumours and tumour-like conditions-such as leukemias-some histologically benign lesions are included (mainly intracranial and intraspinal meningiomas and neurinomas) (1 1). For Acta Paediatr Scand 67
426
J . L.-E. Ericsson et al.
Table 1 . Annual mean population, cancer cases, deaths and deaths from cancer in children 0-14 years, 1958-74 ~~
Cancers Sex
No. of children in population
Boys Girls
853 454 807 912
Deaths
No.
/I@
No.
/lo6
No.
1106
123
142 124
1225 861
1435 1 066
79 62
93 77
101
convenience of presentation all tumours and tumour-like conditions, which are to be reported to the registry and are included in the incidence figures, have been referred to as “cancers” in the following. Histological verification of the lesions was obtained in approximately 95% of the cases. Mortality figures have been obtained from the files of the National Central Bureau of Statistics (12). For the evaluation of incidence and mortality trends, a linear regression analysis based on the observed rates per one million population has been performed. The statistical significance of the trends has been checked by r-test. The linear regression equation used was of the form Y,=a+bX
Table 2. None of the most common childhood cancers are frequent in adults. Hence, leukemias account for about 3%, and tumours of the brain and spinal cord 3.5 %, among adults. Furthermore, Wilms’ tumour of the kidney and neuroblastomas are extremely rare among grown-ups. The frequency of the most common tumours
Table 2. The ten most common cancer sites in children 0-14 years in each sex 1958-74
where Y,=estimated annual incidence rate per one million population Y =observed annual incidence rate per one million population X =calendar year minus 1957, for death rates 1959 a =Y-bX and b =
Cancer deaths
8(x -2)( Y - F) 8(X-8)2
The regression coefficient b has been r-tested with 15 degrees of freedom for incidence rates and 13 degrees of freedom for mortality figures.
RESULTS
In Sweden the average number of new cancer cases in children amounts to approximately 220 annually. Table 1 shows the annual mean population at risk, number of primary cancer cases and number of deaths from cancer. It will be seen that such tumours are somewhat more common in boys than in girls. The most common diagnoses in children are leukemia and tumours of the nervous system which together constitute 58 % of the total. A summary of the ten most common cancer sites is given in Acra Paediatr Scand 67
Site Boys 1. Leukemia 2. Nervous system 3. Malignant non-Hodgkin lymphoma 4. Kidney 5. Bone 6. Eye 7. Connective tissue, muscle 8. Hodgkin’s disease 9. Endocrine glands (except thyroid gland) 10. Testis Other sites
Total Girls 1. Nervous system 2. Leukemia 3. Kidney 4. Eye 5. Bone 6. Connective tissue, muscle 7. Malignant non-Hodgkin lymphoma 8. Ovary 9. Colon (except rectum) 10. Endocrine glands (except thyroid gland)
Other sites Total
No.
%
614 30 581 28 152 7 121 6 115 6 93 4 6 6 3 63 3
48 182
2 2 9
2 086
100
51
504
29 29 7 5 9 0 5 61 4 6 0 4 36 2 32 2
494 126 91
31
2
186
11
1711
100
427
Childhood cancer in Sweden, 1958-1974. I
Table 3. The total number and frequency of the most common cancers with regard to localization and histopathological type in children 0-14 years 1958-1974
Diagnosis
Total number 1958-74
Average no./year 1958-62
Average no./year 1963-68
Average no./year 1969-74
Boys
Girls
Boys
Girls
Boys
Girls
Boys
Girls
28
3.4 2.0 6.0 3.6 16.6 3.2
1.6 0.8 4.0 3.2 16.4 3.2
0.7 0.5 3.5 7.7 22.8 1.8
0.7 I .o 3.2 6.8 16.0 2.2
1.2 0.3 4.3 12.3 16.8 1.3
0.3 0.3 4.0 9.5 11.8 2.2
Leukemia Chronic myelogenous Chronic lymphatic Acute myelogenous Acute lymphatic Acute blast-stem cell Other and unspecified
77 138 32 1 35
14 12 63 114 249 42
Central nervous system Astrocytoma, oligodendroglioma Ependymoma Medulloblastoma Other and unspecified
202 60 88 145
203 62 46 117
9.4 3.2 3.4 7.0
10.6 4.2 3.0 4.8
12.5 2.8 5.8 8.2
12.7 3.7 2.5 6.5
13.3 4.5 6.0 10.2
12.3 3.2 2.7 9.0
Peripheral nerves Neuroblastoma Neurofibrosarcoma Ganglioneuroblastoma Other and unspecified
94 8 7 5
70 12 I2 3
4.4 0.6 0.4 0,2
3.0 1.2 1.o 0.2
4.8 0.7 0.3 0.2
3.3 1.o 0.8 0.3
7.2 0.2 0.5 0.5
5.8 0.3 -
Malignant lymphoma Hodgkin Histiocytic Lymphocytic Other and unspecified
63 39 69 63
27 23 24 23
3.4 3.2 2.2 2.8
1.4 1.8 1.0 1.6
3.0 2.3 4.3 3.8
2.7 1.2 0.8
4.7 1.5 5.3 4.3
0.7 1.2 2.2 1.7
Kidney Wilms’ Other and unspecified
114 7
123 3
6.6 0.6
5.2 0.2
5.7 -
8.5 0.2
7.8 0.7
7.7 0.2
Eye Retinoblastoma Other and unspecified
65 28
52 39
4.4 I .4
2.6 1.6
3.3 I .2
3.2 1.7
3.8 2.3
3.3 3.5
Bone Ewing’s sarcoma Osteosarcoma Other and unspecified
25 51 39
20 37 33
2.0 2.8 3.2
0.6 2.6 1.4
1.7 2.3 1.7
1.3 1.8 1.3
0.8 3.8 2.2
1.5 2.2 3.0
15
and tumour-like conditions with regard to localization and histopathological type during the period under study is given in Tables 3 and 4. Table 3 also shows the changes in frequency during three intervals of this period. Among the leukemias, blast and stem cell forms dominate. The most common tumours in the central nervous system are astrocytomas and related forms (spongioblastomas, oligodendrogliomas), while neuroblastomas predominate in the peripheral nervous system.
1.o
Teratoma is a comparatively common histopathological diagnosis in children (Table 4). Age distribution Almost half of the cancers affect children below 5 years of age (Fig. 1). This is most conspicuous regarding leukemia, Wilms’ tumour and neuroblastoma. Leukemias show a peak between the age of 2 and 4 years. The lowest incidence is noted in the ages 7 to 8 years. Then a slight increase occurs with increasing Acta Paediatr Scand 67
428
J . L.-E. Ericsson et al.
Table 4. The total number of selected histopathological types in children 0-14 years 1958-1 974
Number of cases
Q
Total number 1958-74 Diagnosis Other selected histologicul types Granulosa-theca cell turnour of ovary Teratoma, testis Malignant teratoma (excl. testis) Adenoma of endocrine glands Rhabdornyosarcorna Fibrosarcoma Angiosarcoma Adenocarcinoma Squamous carcinoma Carcinoma, unspecified Malignant mesenchyrnal turnour Carcinoid Malignant melanoma (excl. skin)
Boys
Girls
11 35
15 7 22 17 11 19 3 8
27 8
31 3 10
18 9 51 1
5 20 29 3
10 11 12 13 14 age
Fig. 1 . Age distribution at the time of diagnosis for all cases and selected, large groups. Total number 1958-74.
age dependent on the addition of other forms of tumours, for example those of the skeleton (Fig. 1). A slightly higher incidence is shown for boys than for girls for all ages (Table 1). The sites and cancer forms illustrated in Fig. 1 do not account for the high incidence in the age group 0-1 year. Analysis of this group shows that a number of special turnour forms occur very frequently during the first year of life (Table 5). For instance, slightly over 40% of all malignant tumours of the liver in children were diagnosed in this group. Other malignant tumours with an early predominance include reticuloses and related forms of malignant lymphomas, and malignant tumours of the vulval-vaginal sites.
although considerably less significant (0.7 % annually). The mortality rates during the corresponding period show a decrease, which is most remarkable for girls. Table 6 shows the average annual change in per cent. The trends in incidence and mortality for the three most
Trends in incidence and mortality Year The trends in incidence and mortality for 1958 all cancers during the period 1958-74-as Girls -Boys ,"C - - - - tnc revealed by linear regression analysis-are --- m o l t molt shown in Fig. 2. A significant increase in the Fig. 2. Trends in incidence and mortality for all cancers in incidence rates is noted for boys (2.3% an- the age group 0-14 years during the period 1958-74, as nually). There is also an increase for girls, revealed by linear regression analysis. Acta Paediatr Scund 67
Childhood cancer in Sweden, 1958-1974. I
429
Table 5. Number and per cent distribution of cases diagnosed before the age of one f o r a selected group of sites Boys
Site Liver Vulva, vagina Testis Eye Endocrine glands (except thyroid gland) Connective tissue, muscle Reticuloses and related forms of malignant lymphoma
Girls
No. &I year
Per cent of total 0-14 years
0-1 year
Per cent of total 0-14 years
12 11 26
44 23 28
10 5
42 56
-
-
21
23
10 11
20 17
4 13
13 21
11
58
4
40
No.
common cancers have been studied sepa- the mortality rates appear. On the contrary, there is an increase for boys. Furthermore, rately. For the largest group-leukemia-there is an approximately constant incidence during death rates for both boys and girls are higher the whole period (Fig. 3), while a significant than the incidence rates. In the oldest age decrease in the mortality rates is noted for group studied (10-14 years), there is a tengirls. dency to an overall decrease both in the morLooking at the three age-groups 0-4, 5-9 tality and incidence rates. Again mortality and 10-14 years separately, remarkable dif- rates exceed the incidence rates at the end of ferences are noted in the trends, especially for the period. For figures regarding the different submortality (Figs. 4-6). In the age group 0-4 years there is a significant decrease in the groups of leukemia, reference is made to Tadeath rates, while the incidence rates show a ble 6. slight increase (Fig. 4). In the following age In order to be able to compare the rates of group (5-9 years) no corresponding change in incidence and mortality for tumours of the
Table 6. Mean annual change in incidence and mortality f o r different sites in children 0-14 years, 1958-74 M M
Site All sites Leukemia Nervous system
incid. mort. incid. mort. incid. mort.
Central nervous system
incid.
Neuroblastoma
incid.
Wilms' tumour
incid. mort.
10-14
5-9 F
2.5** 2.0 -2.3*** -2.3* I .2 2.2* -3.8*** -4.4*** 11.9*** 7.0** 4.3*** 1.1
0-14
M
F
M
F
M
2.7 3.1* 3.3*** 6.4** 2.3* 2.3'
-1.0 -0.3 -1.4* -0.4 -2.3 -1.3
1.5 -0.8 -2.4** -1.5 3.0
0.I -1.9 -1.8 -1.0 2.8 -1.1
2.3*** -0.6 0.8 -0.8 6.1*** 2.5***
0.1
F 0.7* -1.5***
-0.5 -2.2*** 2.2*** -0.3
4.l*** 1.0* 3.4*** 11.9*** 1.2** 2.4*** -4.7*** -3,7***
* p
CHILDHOOD CANCER IN SWEDEN. 1958-1974 I. Incidence and mortality J. L.-E. ERICSSON, L. KARNSTROM and BRITTA MATTSSON From the Central Laboratory for Clinical Pathology, University Hospital, University of Uppsala, Uppsala, and Stockholm-Gotland Oncologic Centre, Karolinska Hospital, Stockholm, Sweden
ABSTRACT. Ericsson, J. L.-E., Karnstrom, L. and Mattsson, B. (Central Laboratory for Clinical Pathology, University of Uppsala, Uppsala, and the Stockholm-Gotland Oncologic Centre, Karolinska Hospital, Stockholm, Sweden). Childhood Cancer in Sweden, 1958-1974. I. Incidence and Mortality. Acta Paediatr Scand, 67: 425, 1978.-All cases of tumours and tumour-like conditions in children &14 years reported to the Swedish cancer registry during the period 1958-74 have been studied. The material consists of 3 797 individuals on file in this registry. The most common cancer diagnoses in children &14 years are leukemia and tumours of the central nervous system (together constituting approximately 58 % of all cases). Almost half of the cancers affect children below five years of age. The lowest incidence occurs in the ages 7-8 years, and the highest during the first year of life. The types of tumours below one year of age show a different distribution than in other age groups. A significant increase in the incidence of childhood cancer occurred, while the mortality rates showed a slight decrease during the period studied. A remarkable increase in the incidence figures was noted concerning tumours of the nervous system, especially in boys. The decrease in the mortality rates was most obvious regarding Wilms’ tumour, and leukemia in children 0-4 years of age. KEY WORDS: Childhood cancer, incidence, mortality
Recent evidence stresses the importance of the epidemiologic approach to the study of etiologic factors in the causation of cancer in adults as well as in children. Earlier studies from the Swedish cancer registry have revealed a significant increase in the incidence of malignant tumours since the start of the national registration of incidence of cancer in 1958 (1, 11). Thus, the overall mean annual increases have been 2.3% for males and 1.5% for females, while the mortality rates-as revealed by mortality statisticshave been decreasing slightly over recent decades, with a decrease of 0.4% annually for males and 0.7 % for females. Great variability in the incidence trends of different types of tumours has been noted in Sweden. For instance, primary cancer of the liver has shown an increase of approximately 7 % per year, while cancer of the stomach has decreased by about 2.5 % annually. These re-
sults concern the population as a whole. Knowing that the pattern of cancer diagnoses in childhood differs very much from that in adults , no conclusions concerning childhood cancers can be drawn from the aforementioned studies. It is the purpose of this paper to supply data concerning the incidence and mortality of childhood cancer in Sweden since the inception of the national cancer registry, with special reference to analyses of changes of the rates (trend patterns). MATERIAL AND METHODS All cases of tumours and tumour-like conditions in children 0-14 years reported to the Swedish cancer registry during the period 1958-74 have been studied. The material consists of 3 797 individuals on file in this registry. In addition to histologically clearly malignant tumours and tumour-like conditions-such as leukemias-some histologically benign lesions are included (mainly intracranial and intraspinal meningiomas and neurinomas) (1 1). For Acta Paediatr Scand 67
426
J . L.-E. Ericsson et al.
Table 1 . Annual mean population, cancer cases, deaths and deaths from cancer in children 0-14 years, 1958-74 ~~
Cancers Sex
No. of children in population
Boys Girls
853 454 807 912
Deaths
No.
/I@
No.
/lo6
No.
1106
123
142 124
1225 861
1435 1 066
79 62
93 77
101
convenience of presentation all tumours and tumour-like conditions, which are to be reported to the registry and are included in the incidence figures, have been referred to as “cancers” in the following. Histological verification of the lesions was obtained in approximately 95% of the cases. Mortality figures have been obtained from the files of the National Central Bureau of Statistics (12). For the evaluation of incidence and mortality trends, a linear regression analysis based on the observed rates per one million population has been performed. The statistical significance of the trends has been checked by r-test. The linear regression equation used was of the form Y,=a+bX
Table 2. None of the most common childhood cancers are frequent in adults. Hence, leukemias account for about 3%, and tumours of the brain and spinal cord 3.5 %, among adults. Furthermore, Wilms’ tumour of the kidney and neuroblastomas are extremely rare among grown-ups. The frequency of the most common tumours
Table 2. The ten most common cancer sites in children 0-14 years in each sex 1958-74
where Y,=estimated annual incidence rate per one million population Y =observed annual incidence rate per one million population X =calendar year minus 1957, for death rates 1959 a =Y-bX and b =
Cancer deaths
8(x -2)( Y - F) 8(X-8)2
The regression coefficient b has been r-tested with 15 degrees of freedom for incidence rates and 13 degrees of freedom for mortality figures.
RESULTS
In Sweden the average number of new cancer cases in children amounts to approximately 220 annually. Table 1 shows the annual mean population at risk, number of primary cancer cases and number of deaths from cancer. It will be seen that such tumours are somewhat more common in boys than in girls. The most common diagnoses in children are leukemia and tumours of the nervous system which together constitute 58 % of the total. A summary of the ten most common cancer sites is given in Acra Paediatr Scand 67
Site Boys 1. Leukemia 2. Nervous system 3. Malignant non-Hodgkin lymphoma 4. Kidney 5. Bone 6. Eye 7. Connective tissue, muscle 8. Hodgkin’s disease 9. Endocrine glands (except thyroid gland) 10. Testis Other sites
Total Girls 1. Nervous system 2. Leukemia 3. Kidney 4. Eye 5. Bone 6. Connective tissue, muscle 7. Malignant non-Hodgkin lymphoma 8. Ovary 9. Colon (except rectum) 10. Endocrine glands (except thyroid gland)
Other sites Total
No.
%
614 30 581 28 152 7 121 6 115 6 93 4 6 6 3 63 3
48 182
2 2 9
2 086
100
51
504
29 29 7 5 9 0 5 61 4 6 0 4 36 2 32 2
494 126 91
31
2
186
11
1711
100
427
Childhood cancer in Sweden, 1958-1974. I
Table 3. The total number and frequency of the most common cancers with regard to localization and histopathological type in children 0-14 years 1958-1974
Diagnosis
Total number 1958-74
Average no./year 1958-62
Average no./year 1963-68
Average no./year 1969-74
Boys
Girls
Boys
Girls
Boys
Girls
Boys
Girls
28
3.4 2.0 6.0 3.6 16.6 3.2
1.6 0.8 4.0 3.2 16.4 3.2
0.7 0.5 3.5 7.7 22.8 1.8
0.7 I .o 3.2 6.8 16.0 2.2
1.2 0.3 4.3 12.3 16.8 1.3
0.3 0.3 4.0 9.5 11.8 2.2
Leukemia Chronic myelogenous Chronic lymphatic Acute myelogenous Acute lymphatic Acute blast-stem cell Other and unspecified
77 138 32 1 35
14 12 63 114 249 42
Central nervous system Astrocytoma, oligodendroglioma Ependymoma Medulloblastoma Other and unspecified
202 60 88 145
203 62 46 117
9.4 3.2 3.4 7.0
10.6 4.2 3.0 4.8
12.5 2.8 5.8 8.2
12.7 3.7 2.5 6.5
13.3 4.5 6.0 10.2
12.3 3.2 2.7 9.0
Peripheral nerves Neuroblastoma Neurofibrosarcoma Ganglioneuroblastoma Other and unspecified
94 8 7 5
70 12 I2 3
4.4 0.6 0.4 0,2
3.0 1.2 1.o 0.2
4.8 0.7 0.3 0.2
3.3 1.o 0.8 0.3
7.2 0.2 0.5 0.5
5.8 0.3 -
Malignant lymphoma Hodgkin Histiocytic Lymphocytic Other and unspecified
63 39 69 63
27 23 24 23
3.4 3.2 2.2 2.8
1.4 1.8 1.0 1.6
3.0 2.3 4.3 3.8
2.7 1.2 0.8
4.7 1.5 5.3 4.3
0.7 1.2 2.2 1.7
Kidney Wilms’ Other and unspecified
114 7
123 3
6.6 0.6
5.2 0.2
5.7 -
8.5 0.2
7.8 0.7
7.7 0.2
Eye Retinoblastoma Other and unspecified
65 28
52 39
4.4 I .4
2.6 1.6
3.3 I .2
3.2 1.7
3.8 2.3
3.3 3.5
Bone Ewing’s sarcoma Osteosarcoma Other and unspecified
25 51 39
20 37 33
2.0 2.8 3.2
0.6 2.6 1.4
1.7 2.3 1.7
1.3 1.8 1.3
0.8 3.8 2.2
1.5 2.2 3.0
15
and tumour-like conditions with regard to localization and histopathological type during the period under study is given in Tables 3 and 4. Table 3 also shows the changes in frequency during three intervals of this period. Among the leukemias, blast and stem cell forms dominate. The most common tumours in the central nervous system are astrocytomas and related forms (spongioblastomas, oligodendrogliomas), while neuroblastomas predominate in the peripheral nervous system.
1.o
Teratoma is a comparatively common histopathological diagnosis in children (Table 4). Age distribution Almost half of the cancers affect children below 5 years of age (Fig. 1). This is most conspicuous regarding leukemia, Wilms’ tumour and neuroblastoma. Leukemias show a peak between the age of 2 and 4 years. The lowest incidence is noted in the ages 7 to 8 years. Then a slight increase occurs with increasing Acta Paediatr Scand 67
428
J . L.-E. Ericsson et al.
Table 4. The total number of selected histopathological types in children 0-14 years 1958-1 974
Number of cases
Q
Total number 1958-74 Diagnosis Other selected histologicul types Granulosa-theca cell turnour of ovary Teratoma, testis Malignant teratoma (excl. testis) Adenoma of endocrine glands Rhabdornyosarcorna Fibrosarcoma Angiosarcoma Adenocarcinoma Squamous carcinoma Carcinoma, unspecified Malignant mesenchyrnal turnour Carcinoid Malignant melanoma (excl. skin)
Boys
Girls
11 35
15 7 22 17 11 19 3 8
27 8
31 3 10
18 9 51 1
5 20 29 3
10 11 12 13 14 age
Fig. 1 . Age distribution at the time of diagnosis for all cases and selected, large groups. Total number 1958-74.
age dependent on the addition of other forms of tumours, for example those of the skeleton (Fig. 1). A slightly higher incidence is shown for boys than for girls for all ages (Table 1). The sites and cancer forms illustrated in Fig. 1 do not account for the high incidence in the age group 0-1 year. Analysis of this group shows that a number of special turnour forms occur very frequently during the first year of life (Table 5). For instance, slightly over 40% of all malignant tumours of the liver in children were diagnosed in this group. Other malignant tumours with an early predominance include reticuloses and related forms of malignant lymphomas, and malignant tumours of the vulval-vaginal sites.
although considerably less significant (0.7 % annually). The mortality rates during the corresponding period show a decrease, which is most remarkable for girls. Table 6 shows the average annual change in per cent. The trends in incidence and mortality for the three most
Trends in incidence and mortality Year The trends in incidence and mortality for 1958 all cancers during the period 1958-74-as Girls -Boys ,"C - - - - tnc revealed by linear regression analysis-are --- m o l t molt shown in Fig. 2. A significant increase in the Fig. 2. Trends in incidence and mortality for all cancers in incidence rates is noted for boys (2.3% an- the age group 0-14 years during the period 1958-74, as nually). There is also an increase for girls, revealed by linear regression analysis. Acta Paediatr Scund 67
Childhood cancer in Sweden, 1958-1974. I
429
Table 5. Number and per cent distribution of cases diagnosed before the age of one f o r a selected group of sites Boys
Site Liver Vulva, vagina Testis Eye Endocrine glands (except thyroid gland) Connective tissue, muscle Reticuloses and related forms of malignant lymphoma
Girls
No. &I year
Per cent of total 0-14 years
0-1 year
Per cent of total 0-14 years
12 11 26
44 23 28
10 5
42 56
-
-
21
23
10 11
20 17
4 13
13 21
11
58
4
40
No.
common cancers have been studied sepa- the mortality rates appear. On the contrary, there is an increase for boys. Furthermore, rately. For the largest group-leukemia-there is an approximately constant incidence during death rates for both boys and girls are higher the whole period (Fig. 3), while a significant than the incidence rates. In the oldest age decrease in the mortality rates is noted for group studied (10-14 years), there is a tengirls. dency to an overall decrease both in the morLooking at the three age-groups 0-4, 5-9 tality and incidence rates. Again mortality and 10-14 years separately, remarkable dif- rates exceed the incidence rates at the end of ferences are noted in the trends, especially for the period. For figures regarding the different submortality (Figs. 4-6). In the age group 0-4 years there is a significant decrease in the groups of leukemia, reference is made to Tadeath rates, while the incidence rates show a ble 6. slight increase (Fig. 4). In the following age In order to be able to compare the rates of group (5-9 years) no corresponding change in incidence and mortality for tumours of the
Table 6. Mean annual change in incidence and mortality f o r different sites in children 0-14 years, 1958-74 M M
Site All sites Leukemia Nervous system
incid. mort. incid. mort. incid. mort.
Central nervous system
incid.
Neuroblastoma
incid.
Wilms' tumour
incid. mort.
10-14
5-9 F
2.5** 2.0 -2.3*** -2.3* I .2 2.2* -3.8*** -4.4*** 11.9*** 7.0** 4.3*** 1.1
0-14
M
F
M
F
M
2.7 3.1* 3.3*** 6.4** 2.3* 2.3'
-1.0 -0.3 -1.4* -0.4 -2.3 -1.3
1.5 -0.8 -2.4** -1.5 3.0
0.I -1.9 -1.8 -1.0 2.8 -1.1
2.3*** -0.6 0.8 -0.8 6.1*** 2.5***
0.1
F 0.7* -1.5***
-0.5 -2.2*** 2.2*** -0.3
4.l*** 1.0* 3.4*** 11.9*** 1.2** 2.4*** -4.7*** -3,7***
* p
