Abstract

Background: Survival of cancer patients has been measured only in some limited areas in Japan until recently. The purpose of the present study was to collect data of fairly high quality on the population-based cancer registries and to estimate relative 5-year survival of cancer patients in Japan.

Methods: We requested 11 population-based cancer registries within the research group to submit individual data of the patients diagnosed from 1993 to 1996, together with the prognosis after 5 years, to the collaborative study secretariat. Ten population-based cancer registries (Miyagi, Yamagata, Niigata, Chiba, Kanagawa, Fukui, Aichi, Osaka, Tottori and Nagasaki) then accepted data submission (373 000 data). Among 10 registries, only 7 registries met the required standards for the quality of registration data and prognosis investigation. The relative 5-year survival calculated by pooling 279 000 data from seven registries was taken as the national estimate of that of cancer patients in Japan.

Results: The relative 5-year survival was 53.6% for all cancers (males: 49.2%, females: 59.4%); the survivals of stomach, large bowel, prostate and kidney cancer patients were from 62 to 68%; those of breast, uterus, larynx, skin, testis, bladder and thyroid cancer patients were from 74 to 92%; those of liver, gall bladder and bile duct, pancreas and lung cancer patients ranged from 6 to 23%.

Conclusion: On the basis of the data from seven population-based cancer registries in Japan, we calculated the relative 5-year survival of cancer patients diagnosed from 1993 to 1996 for the first time.

INTRODUCTION

The survival based on population-based cancer registries, being different from the survivals of the cancer patients diagnosed and treated at specific facilities and departments, is a prerequisite for the designing of projects and the evaluation of measures and treatments for cancers, because only the former is capable of providing patients' data without bias. However, in Japan, the survival has been calculated only in limited areas until now. In addition, regarding the survival calculation, study subjects and methods have not yet been standardized enough. Referring to the EUROCARE study (1), the authors tried to develop the standard methods of calculating survival in Japanese registries through the collaborative study of population-based cancer registries since 1996. In 1998, we proposed the standard methods that required that the vital status of patients be confirmed by inquiring to the resident registration at the time of 5 years after diagnosis, and reported the results of relative 5-year survival based on the data (stomach, lung and breast cancer diagnosed from 1985 to 1989) from cancer registries of Yamagata, Fukui and Osaka prefectures (2), which had already started to collect data satisfying the above criteria (3). In 2001, we collected, from 12 registries belonging to the study group, individual data of all cancer patients (for all sites) diagnosed in 1993 with prognosis after 5 years, and tried a nationwide estimate of relative 5-year survival according to the standard methods (4). A nationwide estimate, however, has not been completed because there were differences in the quality of registration and prognosis investigation among 12 registries.

In this study, we requested population-based cancer registries to submit the data of the patients (for all sites) diagnosed from 1993 to 1996 with those on prognosis after 5 years, and pooled the data of the cancer registries that achieved a standard of quality of data in terms of both registration and prognosis investigation in order to estimate relative 5-year survival of cancer patients in Japan.

SUBJECTS AND METHODS

Ten of 11 registries belonging to the research group traced the prognosis after 5 years of patients diagnosed from 1993 to 1996 and submitted their individual data (a total of 373 000 cases) to the research group secretariat. Among 10 registries, 7 registries (Miyagi, Yamagata, Niigata, Fukui, Osaka, Tottori and Nagasaki) met the required standards for the quality of registration and prognosis investigation. According to a total of 279 000 data provided by these registries, we calculated survivals and considered them as nationwide estimates. Standard for the quality of registration was based on the standard adopted in the nationwide estimates of incidence: DCO (death certificate only cases) was <25%, or DCN (death certificate notification) was <30%, and ID ratio (incidence to death ratio) was not <1.5 (5). As far as the standard for the quality of prognoses investigation was concerned, we set two kinds of criteria according to the follow-up methods. For the registries checking survival of patients by referring to inhabitant's registry, the proportion of prognosis-unknown cases 5 years after diagnosis was <5% (Yamagata, Fukui and Osaka). For the registries having no confirmation of survival 5 years after diagnosis, information on personal identification including names would be magnetized in order to collate their registered patients with death information in high accuracy. Therefore, using these criteria, it was guaranteed that they had rather accurate information about death (Miyagi, Niigata, Tottori and Nagasaki).

The method of calculating survival is based on the EUROCARE study (1) in which 12 countries of the European Union had participated in 1990, and our study group also followed this method. In other words, we excluded DCO cases, in situ cancer cases and mucosal cancer cases of large bowel from the analysis. In the case of multiple cancers, only the first-diagnosed tumour was analysed. In calculating survival, cumulative 5-year survivals were calculated starting from the date of diagnosis. Expected survivals were calculated using the cohort survival table based on life tables of the Japanese population and afterwards using the survival probability in the general population similar to the patients in sex, birth-year and age. The former was divided by the latter to obtain relative 5-year survivals. Besides, the cases that were unknown as of 5 years after diagnoses were dealt with as alive as of the last date of living (2). However, regarding four registries that had not yet started to check the survival of patients by referring to the resident registry, we regarded all of the cases whose death was not confirmed as alive until 5 years, and survivals were calculated.

RESULTS

Table 1 shows the number of incidence, validity indices of the registration and the number of study subjects for survival analysis, according to the registry. Total number of incidence was 279 469, and the following cases were excluded from the survival analysis: DCO (49 278 cases, 17.6% of the total incidence), subsequent primary tumours (18 596 cases, 6.7% of the total), not malignant tumours (487 cases, 0.2% of the total), in situ cancers (3955 cases, 1.4% of the total). In addition, excluding the cases of unknown age at diagnosis and the cases over 100 years old, we analysed the rest of all (209 373 cases, 74.9% of the total) (Subjects 1). Moreover, for DCN cases, complementary cancer reports were requested in Yamagata, Fukui and Osaka prefecture, and the registry records of cases originating from death information were distinguished in Miyagi prefecture. The number of cases in which we traced the death information to incidence were 17 556 (8.4% of the total). The analysis subjects (Subjects 2) excluding these cases were 191 817 cases (68.6% of the total).

Table 1.

Number of incidence, validity indices of the registration and number of study subjects for survival, according to the registry—Diagnosed in 1993–96

Registry No. of incidence DCO
 
 Subsequent tumours
 
 Not malignant
 
 In situ
 
 Subjects 1
 
 Follow-back
 
 Subjects 2
 
 

 

 
No.
 
%*1
 
No.
 
%*1
 
No.
 
%*1
 
No.
 
%*1
 
No.
 
%*1
 
No.
 
%*2
 
No.
 
%*1
 
Miyagi 37 372 5865 15.7 4147 11.1 107 0.3 919 2.5 26 997 72.2 115 0.4 26 882 71.9 
Yamagata 24 315 2542 10.5 835 3.4# (2.7) 0.0 250 1.0 20 683 85.1 2481 12.0 18 202 74.9 
Niigata 44 647 10 845 24.3 1605 3.6 0.0 495 1.1 31 715 71.0 — — 31 715 71.0 
Fukui 13 806 581 4.2 0.0# (10.3) 0.0 142 1.0 13 083 94.8 1631 12.5 11 452 82.9 
Osaka 118 931 23 549 19.8 7252 6.1 380 0.3 1546 1.3 87 366 73.5 13 329 15.3 74 037 62.3 
Tottori 10 528 2735 26.0 151 1.4 0.0 23 0.2 7645 72.6 — — 7645 72.6 
Nagasaki 29 870 3161 10.6 4606 15.4 0.0 580 1.9 21 884 73.3 — — 21 884 73.3 
Total 279 469 49 278 17.6 18 596 6.7 487 0.2 3955 1.4 209 373 74.9 17 556 8.4 191 817 68.6 
Registry No. of incidence DCO
 
 Subsequent tumours
 
 Not malignant
 
 In situ
 
 Subjects 1
 
 Follow-back
 
 Subjects 2
 
 

 

 
No.
 
%*1
 
No.
 
%*1
 
No.
 
%*1
 
No.
 
%*1
 
No.
 
%*1
 
No.
 
%*2
 
No.
 
%*1
 
Miyagi 37 372 5865 15.7 4147 11.1 107 0.3 919 2.5 26 997 72.2 115 0.4 26 882 71.9 
Yamagata 24 315 2542 10.5 835 3.4# (2.7) 0.0 250 1.0 20 683 85.1 2481 12.0 18 202 74.9 
Niigata 44 647 10 845 24.3 1605 3.6 0.0 495 1.1 31 715 71.0 — — 31 715 71.0 
Fukui 13 806 581 4.2 0.0# (10.3) 0.0 142 1.0 13 083 94.8 1631 12.5 11 452 82.9 
Osaka 118 931 23 549 19.8 7252 6.1 380 0.3 1546 1.3 87 366 73.5 13 329 15.3 74 037 62.3 
Tottori 10 528 2735 26.0 151 1.4 0.0 23 0.2 7645 72.6 — — 7645 72.6 
Nagasaki 29 870 3161 10.6 4606 15.4 0.0 580 1.9 21 884 73.3 — — 21 884 73.3 
Total 279 469 49 278 17.6 18 596 6.7 487 0.2 3955 1.4 209 373 74.9 17 556 8.4 191 817 68.6 
*1

Proportion to the total incidence.

*2

Proportion to the Subjects 1.

#

Registries or incidence data without items to distinguish multiple tumours. Figures in the parentheses were proportion of those to the total incidence.

DCO: Death certificate only cases; Subsequent tumours: Second and later primary tumours;

Subjects 1: Study subjects for survival, including cases who were followed back and confirmed as incidence according to death information; Follow-back; Cases who were followed back and confirmed as incidence according to death information;

Subjects 2: Study subjects for survival, excluding cases who were followed back and confirmed as incidence according to death information.

Table 2 shows the vital status as of 5 years from diagnosis. In Yamagata, Fukui and Osaka Cancer Registries, where the vital status of patients was checked after 5 years by referring to inhabitant's registry, the proportion of unknown cases for vital status was <2–3%, which indicates that the prognosis investigation was highly accurate.

Table 2.

Vital status as of 5 years from diagnosis

Registry No. of Subjects 1 Dead
 
 Alive
 
 Unknown
 
 

 

 
N
 
%*1
 
N
 
%*1
 
N
 
%*1
 
Yamagata 20 683 11 206 54.2 9307 45.0 170 0.8 
Fukui 13 083 7467 57.1 5197 39.7 419 3.2 
Osaka 87 366 54 199 62.0 31 633 36.2 1534 1.8 
Niigata 31 715 15 144 47.8 16 570 52.2 0.0 
Miyagi 26 997 12 767 47.3 14 230 52.7 — — 
Tottori 7645 3595 47.0 4050 53.0 — — 
Nagasaki 21 884 11 830 54.1 10 054 45.9 — — 
Total 209 373 116 208 55.5 91 041 43.5 — — 
Registry No. of Subjects 1 Dead
 
 Alive
 
 Unknown
 
 

 

 
N
 
%*1
 
N
 
%*1
 
N
 
%*1
 
Yamagata 20 683 11 206 54.2 9307 45.0 170 0.8 
Fukui 13 083 7467 57.1 5197 39.7 419 3.2 
Osaka 87 366 54 199 62.0 31 633 36.2 1534 1.8 
Niigata 31 715 15 144 47.8 16 570 52.2 0.0 
Miyagi 26 997 12 767 47.3 14 230 52.7 — — 
Tottori 7645 3595 47.0 4050 53.0 — — 
Nagasaki 21 884 11 830 54.1 10 054 45.9 — — 
Total 209 373 116 208 55.5 91 041 43.5 — — 
*1

Proportion to the total number of Subjects 1.

Table 3 shows the number of study subjects, relative 5-year survival and its standard error according to the primary site. In addition, when selecting the study subjects, we distinguished between the occasion including the cases regarded as incidence according to death information (Subjects 1) and the occasion excluding the former case. Moreover, regarding the sites covering relatively many subjects, we showed the results of analysis by sex; regarding the sites covering relatively small subjects, we showed only the total results of males and females. Usually, mucosal cancer of large bowel cases should be excluded from the survival analysis (2,6), but some registries (Fukui, Niigata and Tottori) submitted the data including these cases undistinguished. Therefore, regarding all sites, large bowel, colon and rectum, each case was divided between their 1 and 2 on the basis of whether or not mucosal cancer of large bowel was included.

Table 3.

Relative 5-year survival for selected sites of cancer diagnosed in 1993–96

Study subjects
 
Sex
 
Items
 
All sites 1
 
All sites 2
 
Stomach
 
Large bowel 1
 
Large bowel 2
 
Colon 1
 
Colon 2
 
Rectum 1
 
Rectum 2
 
Liver
 
Lung
 
Breast
 
Uterus
 
    
Major sites by sex                    
Male N*1 121 454 119 555 32 195 21 218 19 319 12 987 11 555 8231 7764 12 111 17 671 — —     
  RSR*2 46.0 45.1 59.0 69.5 66.2 72.3 68.5 65.1 62.9 17.0 18.3 — —     
  SE*3 0.2 0.2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.4 0.3 — —     
 Female 87 919 87 037 16 542 15 279 14 397 10 245 9606 5034 4791 4558 6645 14 673 5732     
  RSR 55.2 54.8 57.0 64.6 62.4 65.1 62.7 63.7 61.8 17.4 24.1 83.1 70.5     
  SE 0.2 0.2 0.4 0.4 0.5 0.5 0.6 0.8 0.8 0.6 0.6 0.4 0.7     
 Both 209 373 206 592 48 737 36 497 33 716 23 232 21 161 13 265 12 555 16 669 24 316 14 673 5732     
 sexes RSR 49.9 49.2 58.3 67.5 64.6 69.1 65.8 64.6 62.5 17.1 19.9 83.1 70.5     
  SE 0.1 0.1 0.3 0.3 0.3 0.4 0.4 0.5 0.5 0.3 0.3 0.4 0.7     
Male 111 012 109 113 30 253 20 250 18 351 12 362 10 930 7888 7421 10 081 15 467 — —     
  RSR 50.1 49.2 62.6 72.7 69.5 75.8 72.2 67.8 65.6 20.1 20.7 — —     
  SE 0.2 0.2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.4 0.4 — —     
 Female 80 805 79 925 15 419 14 437 13 557 9615 8978 4822 4579 3685 5756 14 391 5419     
  RSR 59.8 59.4 60.9 68.2 66.0 69.1 66.8 66.4 64.6 21.0 27.6 84.6 74.3     
  SE 0.2 0.2 0.4 0.5 0.5 0.6 0.6 0.8 0.8 0.7 0.6 0.3 0.7     
 Both sexes 191 817 189 038 45 672 34 687 31 908 21 977 19 908 12 710 12 000 13 766 21 223 14 391 5419     
  RSR 54.3 53.6 62.0 70.8 68.0 72.9 69.8 67.3 65.2 20.3 22.6 84.6 74.3     
  SE 0.1 0.1 0.3 0.3 0.3 0.4 0.4 0.5 0.5 0.4 0.3 0.3 0.7     
Minor sites, both sexes combined
 
                   
Study subjects
 
Sex
 
Items
 
Mouth, oral cavity and pharynx
 
Oesophagus
 
Gall bladder and bileduct
 
Pancreas
 
Larynx
 
Skin
 
Ovary
 
Prostate
 
Testis
 
Kidney, etc.
 
Bladder
 
Brain and nervous system
 
Thyroid
 
Lymphoma
 
Myeloma
 
Leukaemia
 
Childhood cancer
 
Both sexes 3699 5820 6501 6393 1693 2182 2492 4681 503 3958 4908 1438 3247 4720 1070 3351 1284 
  RSR 50.9 25.0 17.5 5.5 76.7 87.5 43.8 63.4 90.0 59.2 74.2 31.4 90.3 43.7 25.0 28.1 71.8 
  SE 0.9 0.6 0.5 0.3 1.3 1.3 1.0 1.0 1.4 0.9 0.8 1.3 0.7 0.8 1.5 0.8 1.3 
Both sexes 3527 5396 5622 5301 1657 2130 2169 4348 502 3637 4644 1217 3179 4302 847 2935 1257 
  RSR 53.3 26.8 20.1 6.5 78.2 89.6 50.0 67.6 90.1 64.0 78.1 36.6 92.0 47.8 29.9 31.5 73.4 
  SE 0.9 0.7 0.6 0.4 1.3 1.2 1.1 1.0 1.4 0.9 0.8 1.4 0.6 0.8 1.7 0.9 1.3 
Study subjects
 
Sex
 
Items
 
All sites 1
 
All sites 2
 
Stomach
 
Large bowel 1
 
Large bowel 2
 
Colon 1
 
Colon 2
 
Rectum 1
 
Rectum 2
 
Liver
 
Lung
 
Breast
 
Uterus
 
    
Major sites by sex                    
Male N*1 121 454 119 555 32 195 21 218 19 319 12 987 11 555 8231 7764 12 111 17 671 — —     
  RSR*2 46.0 45.1 59.0 69.5 66.2 72.3 68.5 65.1 62.9 17.0 18.3 — —     
  SE*3 0.2 0.2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.4 0.3 — —     
 Female 87 919 87 037 16 542 15 279 14 397 10 245 9606 5034 4791 4558 6645 14 673 5732     
  RSR 55.2 54.8 57.0 64.6 62.4 65.1 62.7 63.7 61.8 17.4 24.1 83.1 70.5     
  SE 0.2 0.2 0.4 0.4 0.5 0.5 0.6 0.8 0.8 0.6 0.6 0.4 0.7     
 Both 209 373 206 592 48 737 36 497 33 716 23 232 21 161 13 265 12 555 16 669 24 316 14 673 5732     
 sexes RSR 49.9 49.2 58.3 67.5 64.6 69.1 65.8 64.6 62.5 17.1 19.9 83.1 70.5     
  SE 0.1 0.1 0.3 0.3 0.3 0.4 0.4 0.5 0.5 0.3 0.3 0.4 0.7     
Male 111 012 109 113 30 253 20 250 18 351 12 362 10 930 7888 7421 10 081 15 467 — —     
  RSR 50.1 49.2 62.6 72.7 69.5 75.8 72.2 67.8 65.6 20.1 20.7 — —     
  SE 0.2 0.2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.4 0.4 — —     
 Female 80 805 79 925 15 419 14 437 13 557 9615 8978 4822 4579 3685 5756 14 391 5419     
  RSR 59.8 59.4 60.9 68.2 66.0 69.1 66.8 66.4 64.6 21.0 27.6 84.6 74.3     
  SE 0.2 0.2 0.4 0.5 0.5 0.6 0.6 0.8 0.8 0.7 0.6 0.3 0.7     
 Both sexes 191 817 189 038 45 672 34 687 31 908 21 977 19 908 12 710 12 000 13 766 21 223 14 391 5419     
  RSR 54.3 53.6 62.0 70.8 68.0 72.9 69.8 67.3 65.2 20.3 22.6 84.6 74.3     
  SE 0.1 0.1 0.3 0.3 0.3 0.4 0.4 0.5 0.5 0.4 0.3 0.3 0.7     
Minor sites, both sexes combined
 
                   
Study subjects
 
Sex
 
Items
 
Mouth, oral cavity and pharynx
 
Oesophagus
 
Gall bladder and bileduct
 
Pancreas
 
Larynx
 
Skin
 
Ovary
 
Prostate
 
Testis
 
Kidney, etc.
 
Bladder
 
Brain and nervous system
 
Thyroid
 
Lymphoma
 
Myeloma
 
Leukaemia
 
Childhood cancer
 
Both sexes 3699 5820 6501 6393 1693 2182 2492 4681 503 3958 4908 1438 3247 4720 1070 3351 1284 
  RSR 50.9 25.0 17.5 5.5 76.7 87.5 43.8 63.4 90.0 59.2 74.2 31.4 90.3 43.7 25.0 28.1 71.8 
  SE 0.9 0.6 0.5 0.3 1.3 1.3 1.0 1.0 1.4 0.9 0.8 1.3 0.7 0.8 1.5 0.8 1.3 
Both sexes 3527 5396 5622 5301 1657 2130 2169 4348 502 3637 4644 1217 3179 4302 847 2935 1257 
  RSR 53.3 26.8 20.1 6.5 78.2 89.6 50.0 67.6 90.1 64.0 78.1 36.6 92.0 47.8 29.9 31.5 73.4 
  SE 0.9 0.7 0.6 0.4 1.3 1.2 1.1 1.0 1.4 0.9 0.8 1.4 0.6 0.8 1.7 0.9 1.3 

Subjects 1: Including cases who were followed back and confirmed as incidence according to death information.

Subjects 2: Excluding cases who were followed back and confirmed as incidence according to death information.

*1

Number of study subjects.

*2

Relative 5-year survival.

*3

Standard error.

Relative 5-year survival of cancer patients of all sites (all sites 2) was 45.1, 54.8 and 49.2% for males, females and total, respectively, on Subjects 1, and 49.2, 59.4 and 53.6% on Subjects 2; the former is higher than the latter. This is because Subjects 1 includes the cases regarded as incidence according to death information. Same as many registries in Japan, under the situation of high proportion of the cases not reported and the cases registered on the basis of death certificates, it will be possible for the survival calculated on the basis of Subjects 1 to be estimated lower than it is. In contrast, it is also possible for survival to be estimated higher than it is on Subjects 2. In Japan, each population-based registry decides whether or not to request medical institutions to submit information on cancer diagnosis and treatment for DCN. Consequently, if we need domestic comparison of survival, the survival of Subjects 2 would be better than that of Subjects 1 in terms of comparability. Therefore, in this study, we will regard the survival calculated on the basis of Subjects 2 as that of cancer patients in Japan.

The relative 5-year survivals by site on Subjects 2 were calculated as follows: the survivals of cancers of stomach, large bowel, prostate, and kidney were 62–68%; those of cancers of breast, uterus, larynx, skin, testis, bladder and thyroid were 74–92%; those of cancers of liver, gallbladder and bile duct, pancreas and lung were 6–23%.

Table 4 shows observed and relative 1- to 5-year survival by sites. Observed 1- to 5-year survival in all sites 2 were 72.5, 61.1, 54.9, 50.6 and 47.5% in order; relative survival were 74.4, 64.2, 59.0, 55.7 and 53.6% in order.

Table 4.

Cumulative and relative 1- to 5-year survival for selected sites of cancer diagnosed in 1993–96

Primary sites Observed survival
 
    Relative survival
 
    

 
1
 
2
 
3
 
4
 
5
 
1
 
2
 
3
 
4
 
5
 
All sites 2 72.5 61.1 54.9 50.6 47.5 74.4 64.2 59.0 55.7 53.6 
Mouth, oral cavity and pharynx 79.1 62.7 55.8 51.5 47.9 80.8 65.4 59.5 56.1 53.3 
Oesophagus 55.7 37.3 29.9 25.7 23.5 57.3 39.3 32.4 28.6 26.8 
Stomach 75.0 65.5 60.5 57.0 54.4 77.0 69.0 65.4 63.3 62.1 
Large bowel 2 83.8 73.9 67.5 62.9 59.6 86.0 77.8 73.0 69.9 68.1 
Liver 59.9 44.1 33.0 24.2 18.3 61.2 46.1 35.2 26.3 20.4 
Gall bladder and bile duct 41.2 27.3 21.5 18.9 17.2 42.8 29.3 23.7 21.5 20.2 
Pancreas 23.4 11.4 8.0 6.4 5.7 24.2 12.1 8.7 7.1 6.6 
Larynx 91.3 83.8 77.5 72.3 67.2 93.9 88.8 84.5 81.4 78.2 
Lung 52.1 33.5 25.9 22.1 19.5 53.8 35.6 28.3 24.9 22.6 
Skin 92.4 85.0 79.0 74.7 71.0 96.6 93.2 90.7 89.9 89.6 
Breast 96.7 92.3 87.6 84.1 80.9 97.5 93.8 89.9 87.0 84.6 
Uterus 89.0 80.6 76.0 72.8 70.9 90.0 82.2 78.2 75.7 74.3 
Ovary 78.2 64.6 56.2 51.1 48.2 79.0 65.7 57.6 52.6 50.0 
Prostate 88.6 76.2 65.6 57.3 50.2 93.7 85.4 78.0 72.4 67.6 
Testis 94.0 91.0 89.6 89.2 89.0 94.2 91.4 90.2 90.1 90.1 
Bladder 87.1 78.7 73.4 68.5 64.8 90.4 84.7 82.0 79.5 78.1 
Kidney, etc. 80.1 70.4 65.1 60.9 57.0 82.0 73.8 69.8 66.8 64.1 
Brain and nervous sysytem 70.3 50.4 43.2 38.8 35.3 71.1 51.4 44.4 40.1 36.7 
Thyroid 93.8 92.0 90.6 89.2 87.4 94.8 93.9 93.4 92.9 92.0 
Lymphoma 68.5 56.6 50.5 46.5 43.5 70.1 59.0 53.6 50.2 47.8 
Myeloma 70.8 56.2 42.9 33.4 26.1 72.9 59.4 46.6 37.3 29.9 
Leukaemia 59.8 44.0 37.0 32.6 29.9 60.8 45.2 38.4 34.1 31.5 
Childhood cancer 89.9 81.7 77.1 74.7 73.3 89.9 81.7 77.2 74.8 73.4 
Primary sites Observed survival
 
    Relative survival
 
    

 
1
 
2
 
3
 
4
 
5
 
1
 
2
 
3
 
4
 
5
 
All sites 2 72.5 61.1 54.9 50.6 47.5 74.4 64.2 59.0 55.7 53.6 
Mouth, oral cavity and pharynx 79.1 62.7 55.8 51.5 47.9 80.8 65.4 59.5 56.1 53.3 
Oesophagus 55.7 37.3 29.9 25.7 23.5 57.3 39.3 32.4 28.6 26.8 
Stomach 75.0 65.5 60.5 57.0 54.4 77.0 69.0 65.4 63.3 62.1 
Large bowel 2 83.8 73.9 67.5 62.9 59.6 86.0 77.8 73.0 69.9 68.1 
Liver 59.9 44.1 33.0 24.2 18.3 61.2 46.1 35.2 26.3 20.4 
Gall bladder and bile duct 41.2 27.3 21.5 18.9 17.2 42.8 29.3 23.7 21.5 20.2 
Pancreas 23.4 11.4 8.0 6.4 5.7 24.2 12.1 8.7 7.1 6.6 
Larynx 91.3 83.8 77.5 72.3 67.2 93.9 88.8 84.5 81.4 78.2 
Lung 52.1 33.5 25.9 22.1 19.5 53.8 35.6 28.3 24.9 22.6 
Skin 92.4 85.0 79.0 74.7 71.0 96.6 93.2 90.7 89.9 89.6 
Breast 96.7 92.3 87.6 84.1 80.9 97.5 93.8 89.9 87.0 84.6 
Uterus 89.0 80.6 76.0 72.8 70.9 90.0 82.2 78.2 75.7 74.3 
Ovary 78.2 64.6 56.2 51.1 48.2 79.0 65.7 57.6 52.6 50.0 
Prostate 88.6 76.2 65.6 57.3 50.2 93.7 85.4 78.0 72.4 67.6 
Testis 94.0 91.0 89.6 89.2 89.0 94.2 91.4 90.2 90.1 90.1 
Bladder 87.1 78.7 73.4 68.5 64.8 90.4 84.7 82.0 79.5 78.1 
Kidney, etc. 80.1 70.4 65.1 60.9 57.0 82.0 73.8 69.8 66.8 64.1 
Brain and nervous sysytem 70.3 50.4 43.2 38.8 35.3 71.1 51.4 44.4 40.1 36.7 
Thyroid 93.8 92.0 90.6 89.2 87.4 94.8 93.9 93.4 92.9 92.0 
Lymphoma 68.5 56.6 50.5 46.5 43.5 70.1 59.0 53.6 50.2 47.8 
Myeloma 70.8 56.2 42.9 33.4 26.1 72.9 59.4 46.6 37.3 29.9 
Leukaemia 59.8 44.0 37.0 32.6 29.9 60.8 45.2 38.4 34.1 31.5 
Childhood cancer 89.9 81.7 77.1 74.7 73.3 89.9 81.7 77.2 74.8 73.4 

Table 5 shows relative 5-year survivals for major sites of cancer (all sites 2, stomach, large bowel 2, liver, lung, breast and uteri) by sex and age at diagnosis. The relative 5-year survivals for cancers of stomach, liver, lung and uterus decreased markedly in old age; however, the difference was not pronounced in age regarding those for cancers of large bowel 2 and breast. Regarding lung cancer, females had a higher survival than males in all age groups. Besides, the same difference was also observed for the survival of liver cancer, where there was a marked difference in sex. In contrast, females had a lower survival than males in the following sites and ages: the young patients of stomach cancer aged from 15 to 44 years old, and the old patients of large bowel cancer aged over 75 years old.

Table 5.

Relative 5-year survival for major sites of cancer by sex and age at diagnosis

Age at diagnosis All sites 2
 
  Stomach
 
  Large bowel 2
 
  Liver
 
  Lung
 
  Breast Uterus 

 
Male
 
Female
 
Both sexes
 
Male
 
Female
 
Both sexes
 
Male
 
Female
 
Both sexes
 
Male
 
Female
 
Both sexes
 
Male
 
Female
 
Both sexes
 
Female
 
Female
 
15–44 61.9 75.7 70.4 70.3 63.9 67.3 67.8 65.9 67.0 23.4 — 21.9 27.9 29.5 28.4 84.0 85.9 
45–54 53.6 70.6 62.2 67.7 65.6 67.0 68.3 68.2 68.3 20.9 29.4 22 2 25.2 32.6 27.6 84.4 77.5 
55–64 50.8 61.9 54.9 65.8 65.7 65.8 71.1 67.6 69.8 20.8 26.4 21.9 23.9 33.8 26.5 82.8 75.3 
65–74 48.5 56.5 51.5 63.2 64.7 63.7 71.3 69.5 70.5 20.8 21.9 21.2 21.7 31.6 24.2 87.6 69.4 
75– 41.4 43.2 42.3 50.8 49.9 50.4 65.9 59.9 62.7 12.3 10.5 11.5 13.6 16.4 14.5 86.3 48.3 
Age at diagnosis All sites 2
 
  Stomach
 
  Large bowel 2
 
  Liver
 
  Lung
 
  Breast Uterus 

 
Male
 
Female
 
Both sexes
 
Male
 
Female
 
Both sexes
 
Male
 
Female
 
Both sexes
 
Male
 
Female
 
Both sexes
 
Male
 
Female
 
Both sexes
 
Female
 
Female
 
15–44 61.9 75.7 70.4 70.3 63.9 67.3 67.8 65.9 67.0 23.4 — 21.9 27.9 29.5 28.4 84.0 85.9 
45–54 53.6 70.6 62.2 67.7 65.6 67.0 68.3 68.2 68.3 20.9 29.4 22 2 25.2 32.6 27.6 84.4 77.5 
55–64 50.8 61.9 54.9 65.8 65.7 65.8 71.1 67.6 69.8 20.8 26.4 21.9 23.9 33.8 26.5 82.8 75.3 
65–74 48.5 56.5 51.5 63.2 64.7 63.7 71.3 69.5 70.5 20.8 21.9 21.2 21.7 31.6 24.2 87.6 69.4 
75– 41.4 43.2 42.3 50.8 49.9 50.4 65.9 59.9 62.7 12.3 10.5 11.5 13.6 16.4 14.5 86.3 48.3 

DISCUSSION

On the basis of the data from seven population-based cancer registries in Japan that achieved a standard of quality of data in terms of both registration and prognosis investigation, we calculated relative 5-year survival of cancer patients for the first time. On the basis of the standard methods of calculating survival employed in EUROCARE study (1), we estimated the Japanese representative survival for major sites of cancer as well as childhood cancers diagnosed before the age of 15 years. This study estimated the survival not only for the cancers including the followed-back cases from DCN (Subjects 1) but also the cancers excluding them (Subjects 2). The former used the same method as EUROCARE study employed, and it is the estimate that should be utilized for international comparison of survival based on population-based cancer registries. In contrast, the latter is the estimate that should be utilized for domestic comparison of survival in Japan where some registries do not conduct follow-back inquiries according to death information.

Now we would like to discuss the issues for the study in the future. First of all, it is important to improve the quality of registration, because the high proportion of patients not registered will degrade the accuracy of survival estimate. In this study, we required each registry to meet the necessary standards for participating in the nationwide estimates of incidence (5). Therefore, it would be reasonable to assume that the survival in Japan has been calculated on the basis of the fairly accurate data of population-based cancer registries for the first time. However, from the viewpoint of international standards, where the registry data showing DCO >10% for all sites are regarded as poor completeness of registration, the cases not registered are still not negligible in Japan (7). Thus, we have to admit that the validity of survival has not improved to the desired extent. Moreover, it should be taken into consideration that the survival calculated in this study was based on the data submitted by the very limited areas of seven prefectures. If we assume the difference among prefectures, it will be desirable to utilize wider range of data from more prefectural regions.

In the three prefectures where the vital status of patients was checked after 5 years from diagnosis, the proportion of unknown cases for vital status was 3% or less, which implies that the prognosis investigation was highly accurate. However, the other four prefectures did not check the vital status of patients. The fact that they do not check the survival of patients would have a relatively small effect on the overestimation of the survival, because it is estimated that collating with death information can be done with high accuracy in these four prefectures, and that frequency of moving out to different prefectures is relatively low. However, for collecting more accurate data of survival, it is necessary from now on to investigate prognosis of patients by referring to resident registry.

Regarding mucosal cancers of large bowel, we should have excluded them from the survival analysis, since they were regarded as in situ cancers according to the agreement of UICC (6). However, some population-based cancer registries did not distinguish them in this study. Therefore, we calculated the following two cases: the case including mucosal cancer of large bowel (all sites 1, large bowel 1, colon 1, rectum 1) and the case excluding distinguished mucosal cancer (all sites 2, large bowel 2, colon 2, rectum 2). Moreover, it was not easy for some population-cancer registries to distinguish multiple cancers. For more reliable results of survival, it is necessary to distinguish them from other cancers. In this study, however, it seems that the proportion of mucosal cancer of the large bowel and that of multiple cancers except the first-diagnosed tumour were not very large; therefore, it is reasonable to think that they did not affect the result of survival that much.

The EUROCARE study started as a collaborative study of the European Union (1), and it currently involves 67 population-based cancer registries operating in 22 European countries (8). Furthermore, the CONCORD study (9) extends the EUROCARE study to include North America (the USA and Canada), Australia and Japan. In Japan, the cancer registries of Yamagata, Fukui and Osaka prefecture currently participate in this study, all of which have already started to check the vital status of patients after 5 years from diagnosis. It is desirable that more registries will take part in this study. In the CONCORD study, the following studies are developed: Phase 1 study based on existing data of registries; Phase 2 study to investigate clinical data retrospectively by taking samplings from databases of population-based cancer registries; and Phase 3 study on the central review of pathological specimens. Currently, it is only the Phase 1 study that Japan is participating in; however, it will be necessary to build up a framework for our participation in the high-resolution study of Phase 2 and 3. Through our participation in these types of international collaborative studies, it is expected that the reliability of the study on the survival based on population-based cancer registries in Japan will be improved.

In 2005, the Research Group conducted collaborative study on population-based cancer survival with contribution from 11 cancer registries: Miyagi (D. Shibuya), Yamagata (T. Matsuda), Chiba (H. Mikami), Kanagawa (N. Okamoto), Niigata (K. Ogoshi), Fukui (M. Fujita), Aichi (H. Ito), Osaka (H.T.), Tottori (T. Kishimoto), Hiroshima City (N. Nishi) and Nagasaki (M. Soda). The study was supported by a Grant-in-Aid for Cancer Research from the Japanese Ministry of Health, Labor and Welfare (14-2).

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