Japanese Journal of Clinical Oncology

Division of Epidemiology, Aichi Cancer Center Research Institute, Nagoya, Japan

To investigate the change in adult T-cell leukemia incidence between 1983 and 1992 and to evaluate the sensitivity of the nationwide adult T-cell leukemia survey, we estimated adult T-cell leukemia incidence in the Kyushu district, southern Japan, where adult T-cell leukemia is endemic. The incidence of adult T-cell leukemia was calculated from the difference between Kyushu and the rest of Japan in mortality from malignant lymphoid neoplasms, i.e., Kyushu's excess rate was assumed to be due to adult T-cell leukemia. In Kyushu, average annual adult T-cell leukemia cases aged >= 20 years were estimated for men as 252 during the period 1983-87 and 341 during 1988-92, and for women as 201 and 246 respectively. The age-adjusted mortality rate tended to be higher in the latter period [6.29 per 100 000 (95% confidence interval 5.59-7.00) vs. 5.25 (4.60-5.90) in men, and 3.33 (2.85-3.80) vs. 3.18 (2.71-3.66) in women]. By contrast, the registered number of adult T-cell leukemia cases nationwide during 1988-93 was only 35% (203/587) of the estimated number, and the number of registered versus estimated cases decreased with age, especially when cases were >60 years old. In conclusion, the estimated adult T-cell leukemia incidence for 1983-92 increased in the latter half of the period. The estimation suggests that 65% of adult T-cell leukemia cases might be missed by a nationwide survey, and older cases were more likely than younger ones to be missed.

Key words: adult T-cell leukemia (ATL) - Japan - incidence - estimation - nationwide survey

INTRODUCTION

As human T-cell leukemia virus (HTLV-I) is the causative agent for adult T-cell leukemia (ATL) (1 ,2 ), the number of ATL cases depends on the geographical, age- and sex-specific distribution of HTLV-I (3 ). Kyushu, in southern Japan, is the most HTLV-I endemic district in Japan, and more than half of ATL cases determined by a nationwide survey are observed there (3 ).

Since 1980, biennial ATL surveys have been conducted in Japan, initially on a limited basis, and since the 1986-87 survey, on a nationwide comprehensive basis (3 -6 ). These regular hospital-based surveys continue to provide much useful information on the epidemiological features of ATL in Japan. As the sensitivity of these surveys depends primarily on the response of the participating hospitals throughout Japan, other measuring standards are needed to evaluate their sensitivity and to improve the quality of the nationwide survey, thus limiting this potential bias.

The number of ATL cases can be estimated from the incidence of ATL among HTLV-I carriers (7 ). HTLV-I carriers and ATL cases are more prevalent after 40 years of age (8 ). Moreover, it is suspected that there is a birth cohort effect for HTLV-I prevalence by age in Japan (8 -10 ). On HTLV-I prevalence in Japan and in the Kyushu district, the reported data are insufficient to investigate the time trend. Accordingly, it is difficult to estimate the time trend of ATL by its incidence among HTLV-I carriers. Because of this limited HTLV-I prevalence data, a model for its prediction may be necessary.

There is also limited information for the time trend of ATL, because ATL is not classified as an independent group under International Classification of Diseases (ICD), so the number of ATL deaths cannot be directly extracted from Vital Statistics Japan (11 ). Mortality by malignant lymphoid neoplasms (MLNs) in Kyushu district is much higher than in other districts in Japan, because of the high incidence of ATL (3 ). The population of Kyushu is 12% of Japan's total, but the incidence of ATL in Kyushu is more than 10 times higher than in other districts (3 ). It is, therefore, possible to estimate ATL incidence in Kyushu from Vital Statistics using the discrepancy of deaths due to MLNs between Kyushu and other districts of Japan.

To investigate the change of ATL incidence and to evaluate the sensitivity of the nationwide survey of ATL, we estimated the number of ATL cases in Kyushu from Vital Statistics 1983-92 Japan and compared them with the results of the 1988-93 nationwide surveys.

Table 1. Population and number of deaths from malignant lymphoid neoplasms among residents of Kyushu and 39 other prefectures in Japan by sex and years between 1983-7 and 1988-92

	Men				Women
	Population*		Deaths[dagger]		Population*		Deaths[dagger]
	1985	1990	83-87	88-92	1985	1990	83-87	88-92
Fukuoka	1 557 851	1 615 876	131.4	267.8	1 771 522	1 858 374	103.8	191.2
Saga	286 462	290 545	38.8	68.8	336 540	343 811	25.8	37.8
Nagasaki	513 795	513 838	86.8	127.8	602 776	612 157	61.0	88.0
Kumamoto	609 575	618 545	69.4	136.8	713 920	732 412	54.2	82.6
Oita	412 896	417 236	50.6	76.2	485 736	493 954	35.2	64.2
Miyazaki	381 816	385 474	53.2	84.6	447 307	457 309	44.2	72.0
Kagoshima	595 361	596 371	120.4	170.4	709 544	716 985	88.4	118.4
Okinawa	365 356	385 765	54.4	79.6	391 414	419 534	40.0	52.2
Kyushu[Dagger]	4 723 112	4 823 650	605.5	1009.0	5 458 759	5 634 536	452.6	706.4
Othersw	36 559 554	38 669 904	2465.4	5137.0	35 823 907	40 984 368	2619.0	3416.6

^*Population >20 years of age; ^[dagger]Annual deaths on average over 5 year period from malignant lymphoid neoplasms (ICD9: 200-202,204), >20 years of age; ^[Dagger]Includes the 8 prefectures as follows: Fukuoka, Saga, Nagasaki, Kumamoto, Oita, Miyazaki, Kagoshima and Okinawa; ^wIncludes the 39 Japanese prefectures other than the 8 prefectures of Kyushu.

SUBJECTS AND METHODS

Age- and sex-specific deaths in people aged >= 20 years from MLNs (ICD, version 9: 200, 201, 202 and 204) between 1983 and 1992 were obtained from Vital Statistics Japan (11 ). This information was obtained from a copy of magnetic tape of Vital Statistics provided by the Ministry of Health and Welfare. The estimated number of ATL cases was calculated under the following assumptions: 1, the mortality rate due to MLNs other than ATL does not differ between Kyushu and other districts of Japan; 2, the mortality rate due to ATL contributed less to the total mortality rate from MLNs in districts other than Kyushu; 3, most ATL cases died within one year of onset; 4, excess death rate from MLNs in Kyushu over that of other districts was due to the high incidence of ATL (12 -15 ). As the annual number of ATL cases in each prefecture of Kyushu was expected to be small, deaths from MLNs were pooled during 1983-87 and 1988-92 to reduce random errors. The expected number of deaths from MLNs other than from ATL in Kyushu district were estimated from the age- and sex-specific death rate in other districts. Deaths from ATL were, then, estimated from the difference between actual and expected deaths from MLNs in Kyushu. The annual death rate from ATL was similar to the estimated incidence rate of ATL, because most ATL patients died within a year (4 ). The present study used Japanese census data from the years 1985 and 1990 and classified the group population by age and sex.

The age-adjusted mortality rate among the general population aged >= 20 years in Kyushu was standardized with the Japanese `model' population of 1985 as the denominator (16 ).

The details of the nationwide survey of ATL have been described elsewhere (3 -6 ,17 -19 ). In brief, seven biennial nationwide surveys were conducted from 1980 to 1993. The hospitals participating in the survey were selected from hospitals with >= 200 beds, and these hospitals were judged to possess the ability to care for ATL. The common diagnostic criteria of ATL, T cell malignancies with HTLV-I infection, and valid cases of ATL for the surveys were used. A common questionnaire for case registration was sent to the president, the hematologist and/or dermatologist of each hospital, and these people were requested to report any case of ATL (17 -19 ).

RESULTS

The male and female population of the 8 prefectures of Kyushu and of the 39 other Japanese prefectures increased between 1985 and 1990 (Table 1 ). Average annual number of deaths from MLNs in men both of Kyushu and of any of the other prefectures increased in the latter half of 1983-92. Similar trends were also observed in women. The population increase in Kyushu from 1985 to 1990 was 2.7% among those aged >= 20 years, and 18.6% among those aged >= 60 years (data not shown in the Table).

Age-adjusted mortality rate per 100 000 for the whole of Kyushu in 1988-92 showed an average increase of 19.8% among men [5.25 (95% confidence interval 4.60-5.90) in 1983-87 vs. 6.29 (5.59-7.00) in 1988-92], and of 4.7% among women [3.18 (2.71-3.66) in 1983-87 vs. 3.33 (2.85-3.80) in 1988-92] (Table 2 ). This increasing trend was shown in most prefectures of Kyushu, but none of the differences of age-adjusted mortality rates was statistically significant. A higher mortality rate from ATL was revealed in Okinawa, Kagoshima, Miyazaki and Nagasaki prefectures than in other prefectures. The mortality rate was higher in men than in women in every prefecture. The crude mortality rates for estimated ATL in Kyushu were 4.4 (4.0-4.9) in 1983-87 and 5.6 (5.2-6.1) in 1988-92 (data not shown in table).

Table 2. Estimated number of adult T-cell leukemia (ATL) cases and age-adjusted mortality rate among residents of Kyushu in Japan by sex and 5 year period between 1983-7 and 1988-92

	Men				Women
	Annual number		Age-adjusted mortality rate* (95% confidence interval)		Annual number		Age-adjusted mortality rate* (95% confidence interval)
	83-87	88-92	83-87	88-92	83-87	88-87	83-87	88-92
Fukuoka	26	50	1.67 (1.03-2.32)	3.02 (2.17-3.87)	28	36	1.46 (0.89-2.02)	1.55 (0.98-2.11)
Saga	16	20	5.52 (2.80-8.25)	6.21 (3.35-9.08)	10	10	2.46 (0.79-4.14)	2.38 (0.75-4.01)
Nagasaki	47	63	8.75 (6.20-11.3)	10.32 (7.55-13.1)	33	39	4.69 (2.96-6.42)	4.67 (2.96-6.38)
Kumamoto	22	37	3.26 (1.83-4.69)	5.09 (3.31-6.87)	20	22	2.20 (1.11-3.29)	2.34 (1.23-3.45)
Oita	18	14	3.86 (1.97-5.76)	2.75 (1.16-4.34)	12	18	2.11 (0.82-3.41)	2.82 (1.34-04.30)
Miyazaki	24	33	6.01 (3.55-8.47)	7.27 (4.58-9.96)	24	33	4.74 (2.72-6.76)	5.53 (3.37-7.68)
Kagoshima	71	84	10.56 (7.95-13.2)	11.33 (8.63-14.0)	52	65	5.91 (4.12-7.70)	6.24 (4.41-8.06)
Okinawa	33	42	11.28 (7.84-14.7)	12.25 (8.76-15.7)	24	25	5.86 (3.46-8.26)	5.22 (3.03-7.40)
Kyushu	252	341	5.25 (4.60-5.90)	6.29 (5.59-7.00)	201	246	3.18 (2.71-3.66)	3.33 (2.85-3.80)

^*Age-adjusted mortality rate per 100 000 and year, standardized on the age distribution of the Japanese `model' population aged >= 20 years in 1985.

The estimated number of ATL cases in 1983-87 and in 1988-92 were highest at the age of 60-64 years in men. The age-specific mortality rate in men increased with age until 70 years. In 1983-87, it decreased after 70 years of age, but in 1988-92 it increased after 70 years of age (Fig. 1 ). In women, the estimated numbers of ATL cases in 1983-87 were highest in the age range 60-64 years, but in 1988-92 this shifted slightly to the older age group. The age-specific mortality rate in women increased with age until 80 years of age. Its rate in 1988-92 was higher than that in 1983-87 after 70 years of age (Fig. 2 ).

Figure 1. Men: age-specific distribution of number of estimated adult T-cell leukemia (ATL) cases and mortality rate for ATL in Kyushu district among men for 1983-87 and 1988-92. [squf], estimated cases for 1983-87; =, estimated cases for 1988-92; (-), mortality rate for 1983-87; [middot][middot][middot][middot][middot][middot][middot], mortality rate for 1988-92.

Figure 2.Women: age-specific distribution of number of estimated adult T-cell leukemia (ATL) cases and mortality rate for ATL in Kyushu district among women for 1983-87 and 1988-92. [squf], estimated cases for 1983-87; = estimated cases for 1988-92; (-), mortality rate for 1983-87; [middot][middot][middot][middot][middot][middot][middot], mortality rate for 1988-92.

The proportional distribution of estimated cases of ATL by age group was compared with registered cases from the 7th nationwide ATL survey in 1992-93. The age distribution of the nationwide surveyed cases shifted to younger age groups in both men and women (Fig. 3 ).

When the annual ATL cases in Kyushu district estimated from Vital Statistics in 1988-92 were compared with those registered from the 5th-7th nationwide surveys conducted between 1988-93 by sex and age groups, the registered rate versus the estimated cases decreased according to age in both men and women, especially after 60 years of age. The registered rate for 20-59 years showed a higher rate in women than in men (Table 0 ).

Table 3. Annual number of adult T-cell leukemia (ATL) cases in Kyushu district by prefectures: estimate from Vital Statistics and registered rate from 5th-7th nationwide surveys, and the registered rate from the nationwide survey as % of estimate

		Annual number (%) of cases		Registered rate
Age group (years)		Estimate from Vital Statistics*	Registered from nationwide survey[dagger]	as % of estimate
Men
	20-39	11 (3%)	5 (4%)	45%
	40-59	95 (28%)	44 (39%)	46%
	60-74	151 (44%)	51 (45%)	34%
	75+	84 (25%)	14 (13%)	17%
	Total	341 (100%)	114 (100%)	33%
Women
	20-39	7 (3%)	5 (5%)	71%
	40-59	56 (23%)	40 (45%)	71%
	60-74	104 (42%)	33 (37%)	32%
	75+	79 (32%)	11 (12%)	14%
	Total	246 (100%)	89 (100%)	36%
Men & women
	20-39	18 (3%)	10 (4%)	56%
	40-59	151 (26%)	84 (40%)	56%
	60-74	255 (43%)	84 (42%)	33%
	75+	163 (28%)	25 (13%)	15%
	Total	587 (100%)	203 (100%)	35%

^*Annual number of estimated ATL cases from 1983-87 and 1988-92; ^[dagger]annual number of registered ATL cases from 5-7th nationwide surveys from 1988-93.

Table 4. Annual number of adult T-cell leukemia (ATL) cases in Kyushu district by prefectures: estimate from Vital Statistics and registered rate from 5th-7th nationwide surveys, and the response rate from hospitals in the 7th nationwide survey

	Estimate from Vital Statistics		Registration from nationwide surveys
	Number (%) of cases	Number (%) of cases	Number (%) of cases	Registered rate (% of estimate[dagger])	Response rate from hospitals[sect]
	1983-87*	1988-92*	1988-93[dagger]	1988-93	1992-93
Fukuoka	54 (12%)	86 (15%)	33 (16%)	38%	49%
Saga	26 (6%)	30 (5%)	8 (4%)	27%	56%
Nagasaki	80 (18%)	102 (17%)	44 (22%)	43%	58%
Kumamoto	42 (9%)	59 (10%)	11 (5%)	19%	44%
Oita	30 (7%)	32 (5%)	16 (8%)	50%	53%
Miyazaki	48 (11%)	66 (118)	30 (15%)	45%	57%
Kagoshima	123 (27%)	149 (258)	36 (18%)	24%	40%
Okinawa	57 (138)	67 (11%)	25 (12%)	37%	38%
Kyushu	453 (100%)	587 (100%)	203 (100%)	35%	49%

^*Annual number (% of Kyushu total) of estimated ATL cases from 1983-87 and 1988-92; ^[dagger]annual number of registered ATL cases from 5th-7th nationwide surveys between 1988-93; ^[Dagger]registered rate from 5th-7th nationwide survey as % of the estimated cases in 1988-92; ^[sect]response rate from 206 hospitals of Kyushu district from 7th nationwide survey in 1992-93.

The registered rate versus the estimated cases varied between prefectures in the Kyushu district, and the registered rate for Kyushu as a whole was 35% of the estimated rate. Higher response rates from hospitals were not always accompanied by higher registered rates in each prefecture (Table 0 ).

DISCUSSION

Several assumptions were made when ATL cases were estimated from Vital Statistics. The death rate due to malignant lymphomas in the Kyushu district is markedly higher in the over-40 age group than that in any of the other districts of Japan, where the death rates from malignant lymphomas are not very different from each other (12 ). A similar pattern is also observed in lymphocytic leukemia, but there is no difference in age-specific mortality rates for multiple myeloma and myelocytic leukemia between Kyushu and the rest of Japan (l2 ). The age-specific mortality rates of childhood malignant lymphomas and lymphocytic leukemia in Kyushu are very similar to those of the rest of Japan (12 ), and malignant lymphomas in children were not clustered in Kyushu (13 ). The ratio of T-cell lymphoma to B-cell lymphoma has been reported as being extremely high in Kyushu compared with the rest of Japan (13 ). The incidence of Hodgkin's disease in Kyushu was higher than that of the rest of Japan before 1972, but this difference was voided after 1977 when ATL was discovered (1 ,14 ). All of these Kyushu-specific findings can be explained by the excess incidence of ATL in Kyushu and is concordant with the present assumptions that the excess death rate for MLNs in Kyushu over that in other districts is due to the high incidence of ATL, and that the mortality rate due to MLNs other than ATL does not differ between Kyushu and other districts of Japan.

Figure 3. Comparison of proportional sex-specific distribution between estimated adult T-cell leukemia (ATL) cases in Kyushu and registered cases on 7th Nationwide ATL Study.[middot][middot][middot][middot][middot][middot][middot], estimated cases for 1983-87; (-), estimated cases for 1988-92; (-), 7th nationwide study.

It has been estimated that there were 607 300 HTLV-I carriers in Kyushu and 553 200 in all other districts of Japan in 1986-87 (3 ). If the ATL incidence of 0.6 per l000 adult HTLV-I carriers is used, annual incidence of ATL in Kyushu and other districts are calculated to be 364 and 333 respectively (3 ). These numbers were 34% [364/(605.5+ 452.6)] of annual deaths from MLNs in Kyushu and 7% [333/(2465.4+2619.0)] of those in the rest of Japan between 1983 and 1987. From these facts, it can be assumed that the mortality for ATL contributes less to the total mortality for MLNs in districts other than Kyushu. However, the estimated ATL cases in the present study were slightly underestimated, because a small incidence for ATL was included in the expected rate for MLNs in the districts other than Kyushu.

Patients with acute- and lymphoma-type ATL who showed poor prognosis, and whose 50% survival time was <6 months (15 ), occupied 89% of total ATL cases (l9). Therefore, it could be assumed that most ATL cases died within one year of onset. Moreover, the mortality rate from ATL is close to the incidence rate of ATL.

The accuracy of death certificate for autopsy diagnosis has been evaluated among atomic bomb survivors (20 ). The sensitivity and the specificity of hematopoietic neoplasms were 68.4% and 99.7% respectively. If these results are applied to the present estimation, the estimated number of ATL cases may be underestimated, but would rarely be misclassified.

The risk of ATL among HTLV-I carriers has been calculated by Tokudome et al. (2l,22 ), Kondo et al. (23 ), Murphy et al. (24 ) and Tajima et al. (7 ). Tajima et al. have estimated from Vital Statistics that the number of deaths from ATL in the Kyushu district was 321 per year in 1978-82, although lymphocytic leukemia was not included and subjects were >40 years old (7 ). Some diagnostic difference between lymphoma and leukemia on death certificates for ATL might exist between the 1978-82 period and the 1983-92 period because diagnostic procedures for ATL were not yet commonplace among clinicians during 1978-82. It is therefore difficult to compare the time trend of ATL between 1978-82 and 1983-92.

The number of estimated ATL cases for 1983-92 increased in the latter half of the period. The increment in age-adjusted mortality rate was not statistically significant, but the age-specific mortality rate markedly increased among the older groups. The general population aged >60 years in Kyushu in 1990 was 18.6% higher than in 1985. It is suggested that this increase in the older population, including HTLV-I carriers, influenced the recent increase in ATL cases. Furthermore, the improvement in diagnostic procedures for ATL, especially among the older groups, could also play a minor role in this recent increase. It is possible that older HTLV-I carriers may have a higher risk of developing ATL because of their improved life spans. As the number of annual ATL cases is small, longer investigation is required to get a more stable time trend.

The discrepancy between registered cases from nationwide survey and the estimated cases from Vital Statistics showed that 65% of ATL cases in the Kyushu district might have missed registration in the nationwide surveys during 1988-93. The registered rate for the estimated cases decreased with age, especially after 60 years of age. This suggests that older cases were more likely to be missed from the nationwide survey. Therefore, to increase the sensitivity of a nationwide survey, it will be effective to focus a more sensitive survey on older cases. Detailed comparison of the cases between nationwide survey and cancer registry or death certificates will provide useful information on such problems.

In conclusion, the estimated ATL incidence from 1983-92 tended to increase in the latter half of the period. The estimation suggests that 65% of ATL cases might be missed by a nationwide survey, and older cases were more likely than younger cases to be missed.

Acknowledgements

This work was supported in part by a Grant-in-Aid for Cancer Research from the Ministry of Education, Science and Culture.

References

1. Takatsuki K, Uchiyam;a J, Sagawa K, Yodoi J. Adult T-cell leukemia in Japan. In: Sano S, Takaku F, Irino S, editors. Topics in Hematology. Amsterdam: Excerpta Medica, 1977:73-7.

2. Hinuma Y, Nagata K, Hanaoka M, Nakai M, Matsumoto T, Kinoshita K et al. Adult T-cell leukemia: Antigen in an ATL cell line and detection of antibodies to the antigen in human sera. Proc Natl Acad Sci USA 1981;78:6476-86. MEDLINE Abstract

3. Tajima K. The T- and B-cell malignancy Study Group: The 4th nationwide study of adult T-cell leukemia/lymphoma (ATL in Japan): Estimates of risk of ATL and its geographical and clinical features. Int J Cancer 1990;45:237-43. MEDLINE Abstract

4. The T- and B- cell Malignancy Study Group. Statistical analysis of immunologic, clinical and histopathologic data on lymphoid malignancies in Japan. Jpn J Clin Oncol 1981;11:15-38.

5. The T- and B- cell Malignancy Study Group. Statistical analyses of clinico-pathological, virological and epidemiological data on lymphoid malignancies with special reference to adult T-cell leukemia/lymphoma: A report of the second nationwide study of Japan. Jpn J Clin Oncol 1985;15:517-35.

6. The T- and B- cell Malignancy Study Group. The third nationwide study on adult T-cell leukemia/lymphoma (ATL) in Japan: Characteristic patterns of HLA antigen and HTLV-I infection in ATL patients and their relatives. Int J Cancer 1988;41:505-12.

7. Tajima K, Kuroishi T. Estimation of rate of incidence of ATL among ATLV (HTLV-I) carriers in Kyushu, Japan. Jpn J Clin Oncol 1985;15:423-30. MEDLINE Abstract

8. Tajima K, Ito S. Tsushima ATL study group: Prospective studies of HTLV-I and associated disease in Japan. In: Blattner WA, editor. Human Retrovirology HTLV-I. New York: Raven Press, 1990: 267-80.

9. Ueda K, Kusuhara K, Tokugawa K, Miyazaki C, Yoshida C, Tokumura K. Cohort effect on HTLV-I seroprevalence in southern Japan. Lancet 1989;2:979. MEDLINE Abstract

10. Takezaki T, Tajima K, Komoda H, Imai J. Incidence of human T-lymphotropic virus type I seroconversion after age 40 among Japanese residents in an area where the virus is endemic. J Infect Dis 1995;171:559-65. MEDLINE Abstract

11. Statistics And Information Department, Minister's Secretatiat, Ministry Of Health And Welfare. Vital Statistics Japan, 1983-1992.

12. Kato I, Tajima K, Kuroishi T, Hirose K, Nakagawa N, Tominaga S. A descriptive epidemiological study of hematopoietic neoplasms in Japan. Jpn J Clin Oncol 1985;15:347-64. MEDLINE Abstract

13. Tajima K, Tominaga S, Kuroishi T, Shimizu H, Suchi T. Geographical features and epidemiological approach to endemic T-cell leukemia/lymphoma in Japan. Jpn J Clin Oncol 1979;9:495-504.

14. Tajima K, Suchi T, Hirose K, Kuroishi T, Tominaga S. Re-evaluation of high incidence of Hodgkin's disease in Kyushu, Japan. Hematol Oncol 1984;2: 373-80. MEDLINE Abstract

15. Shimoyama M, Ota K, Kikuchi M, Yunoki K, Konda S, Takatsuki K et al. Major prognostic factors of adult patients with advanced T-cell lymphoma/leukemia. J Clin Oncol 1988;6:1088-97. MEDLINE Abstract

16. Abe Y, Onodera M, Kamiya K, Saito F, Matsue T. On the revision of the age-adjusted death rate. Kousei No Shihyo 1991;38:12-16 (in Japanese).

17. The T- and B- cell Malignancy Study Group. A report of the fifth nationwide study of Japan - Evaluation of fourth nationwide survey. Gan No Rinsho 1992;38:405-16 (in Japanese).

18. The T- and B- cell Malignancy Study Group. A report of the sixth nationwide study of Japan. Gan No Rinsho 1996;40:229-46 (in Japanese).

19. The T- and B- cell Malignancy Study Group. A report of the seventh nationwide study of Japan. Gan No Rinsho 1996;42:231-47 (in Japanese).

20. Ron E, Carter R, Jablon S, Mabuchi K. Agreement between death certificate and autopsy diagnoses among atomic bomb survivors. Epidemiology 1994;5:48-56. MEDLINE Abstract

21. Tokudome S, Tokunaga O, Shimamoto Y, Miyamoto Y, Sumida I, Kikuchi M et al. Incidence of adult T-cell leukemia/lymphoma among human T-lymphotropic virus type I carriers in Saga, Japan. Cancer Res 1989;49:226-8. MEDLINE Abstract

22. Tokudome S, Maeda Y, Fukada K, Teshima D, Asakura T, Sueoka E et al. Follow-up of asymptomatic HTLV-I carriers among blood donors in Kyushu, Japan. Cancer caus Control 1991;2:75-8. MEDLINE Abstract

23. Kondo T, Kono H, Miyamoto N, Yoshida R, Toki H, Matsumoto I et al. Age- and sex-specific cumulative rate and risk of ATLL for HTLV-I carriers. Int J Cancer 1989;43:1061-4. MEDLINE Abstract

24. Murphy EL, Hanchard B, Figueroa JP, Gibbs WN, Lofters WS, Campbell M et al. Modelling the risk of adult T-cell leukemia/lymphoma in persons infected with human T-lymphotropic virus type I. Int J Cancer 1989;43:250-3. MEDLINE Abstract

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Received August 28, 1996; accepted December 13, 1996
For reprints and all correspondence: Toshiro Takezaki, Division of Epidemiology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya 464, Japan
Abbreviations: HTLV-I, human T-cell leukemia virus; ATL, adult T-cell leukemia; ICD, International Classification of Diseases; MLNs, malignant lymphoid neoplasms.

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