膀胱癌に関する研究 第1編: 日本人膀胱癌の統計的および疫学的研究

Abstract

Epidemiological studies were performed on a total of 198 patients with cancer of the urinary bladder, consisting of 163 males and 35 females, treated at the Department of Urology of Kyoto University Hospital during the period from April 1962 to June 1966 (Table 5). Diagnosis on these cases was made based on the results of cystoscopic and histological findings as primary cancer of the bladder. Controls, to be done similar epidemiological studies, were selected from patients visited at out-patient clinic who were adjusted for age and resident distributions to the cancer patients, numbered 163 males and 59 females. On the other hand, observations were made on yearly change of death rate of cancer of the urinary bladder in Japan based on the vital statistics, to study the sex and age adjusted incidence. Literatures were reviewed to discuss comparative findings on cancer of the bladder in domestic and foreign countries on pathogeographic point of view. Results are summraized as follows. 1) Yearly distribution of number of death due to cancer of the bladder showed a trend of marked increase in Japan. During the period of 16 years from 1947 to 1962, number of death increased almost every year. Comparing in 1962 to in 1947, the increases were 3.5 times in males and 2.9 times in females for number of death, 2.8 times in males and 2.4 times in females for crude death rate and 2.3 times in males and 1.8 times in females for age-adjusted death rate. The age-adjusted death rate of all malignant neoplasm during the same period showed slow increase, namely from 100.2 in 1947 to 135.4 in 1962 in males and 82.8 in 1947 to 95.2 in 1962 in females (Table 1, Fig . 1, 2). It was considered that the cause of increase in incidence of cancer of the bladder must be clarified as an urgent problem. 2) A s sex prevalence, the male to female ratio among a total of 259 patiants with cancer of the bladder entered in the Department of Urology of Kyoto University Hospital during the period from 1954 to 1966 was found to be 4.6 with marked male predominance. However, a total of 304 cases of autopsied cancer of the bladder collected from the Annual of the Pathological Autopsy Case of Japan from 1959 to 1962 showed the ratio being 2.5 with male predominance. In addition, the ratio among 12, 926 cases of death due to cancer of the bladder collected from Japanese Vital Statistics from 1947 to 1962 was counted as 1.6 which was less male predominance. These figures indicated that sex prevalence of this disease vary by the materials collected (Table 2, 3). 3) As age distribution of this disease, a nalysis of 259 clinical cases seen in the Department of Urology of Kyoto University Hospital showed most frequent occurrence in the 7th decade, being 40.4 %, followed by in the 6th decade 28.2% and 8th decade 16.0 %, with the total of over 50 years of age groups being 86.3% in males. However in females, although the total of over 50 years of age group occupies 82.5 %, the percentages of 6th, 7th decades and 8th decades were 30.4 %, 28.2 % and 19.6 % respectively, which showed less sex differences than males (Table 2). The crude death rate of cancer of the bladder by age-group in Japan in 1962 showed higher rates in male than female in every age group and sudden increases in both sexes over 45 years of age with further rise in accompamied with advancing of age (Fig. 3). The yearly change of age specific death rate of cancer of the bladder during the period from 1947 to 1962 demonstrated increasing trends in over 50 years of age groups in males and in over 60 years of age groups in females (Fig. 4). These figures dislosed that recent increase in death rate due to cancer of the bladder is attributed to the increases of the disease in over 50 years of age groups in male and in over 60 years of age groups in females. 4) Comparing the age-adjust e d death rates of cancer of the bladder in Japan to in foreign countries (20 countries) in 1958 and 1959, higher rates were seen in South Africa, England and Wales, Scotland, Denmark, New Zealand and United States (white) with the lowest country being in Japan in males. In females, the rate was high in United States (nonwhite), Denmark, Scotland, England and Wales, Canada and United States (white) with the lowest country being also in Japan (Fig. 5). Comparison of age standardized death rates in Japan and in foreign countries from 1952 to 1956 showed similar tendencies. The foreign countries having low rate as in Japan were Chile for male and Venezuela for female (Table 4). There was a tendency that low rates of cancer of the lung and high rates of cancer of the stomack were seen in the countries having low rates of cancer of the bladder (Fig. 8). The death rate of cancer of the bladder showed marked increasing trend in both sexes in England and Denmark, and increasing trend in male in the United States (Fig. 6). 5) The total of 198 cases of this series was devided into 3 grops accord i ng to residence, large city (over 1 million), city and rural districts, and compared to control groups which were selected from patients entered in the Department during same period and matched by sex and age distributions. No statistically significant difference was observed on the residential distribution between the cancer patients and the controls (x2= 2.460, 0=2, 0.25<p<0.50) (Table 6). 6) On analysis of occupationa l status of 160 male patients, a remarkably frequent occurrence than control was demonstrated among workers on textiles which was statistically significant difference at risk of below 0.5% (x2=8.711, p<0.005). Among 15 cases with such occupation 7 cases were dyers (Table 7). This result suggests an importance of well managed superintendence not only in dye producting process but also in handling stained products which may contain causal substances. 7) ABO blood type distribution i n 447 cases of cancer of the bladder collected in Kyoto, Osaka and Nara showed 36.6% for A, 26.0% for B, 27.1% for 0 and 10.3% for AB. Since blood type distribution of 530, 046 populations of Japanese in general is 38.3%, 21.8%, 30.5% and 9.4% for A, B, 0 and AB types respectively, patients with cancer of the bladder have frequent B-type with the significance below 5% (x2=4.544, 0.010<p<0.050) (Table 8). Distribution of ABO blood type in the population of this district is virtually same as that of in all Japanese population. Therefore high percentage of B-type in patients with cancer of the bladder with significance at less than 5% risk is not considered to be attributable to geographical difference in this district. This specific findings on blood type in patients with this disease have not appeared in the literatures so far and need particular consideration. 8) Among 163 male patient studied, 23.9% stated history of venerial diseases, which showed marked significant difference in comparison with 11.1% obtained from the control group (x2=9.376, p<0.005) (Table 9). Although immediate relationship is hard to be considered between history of venerial diseases and cancer of the bladder, it will be necessary to carry on further evaluations on environmental factors of persons who get venerial diseases or their somatic factors. 9) Serological test f or syphilis performed in 82 patients with cancer of the bladder and 228 patients with cancer of the gastrointestinal tract gave positive results in 15.8% for the former and 8.8% for the latter. Although the figure of percentage is higher in the cancer of the bladder, x2-test showed x2=3.180 at risk of 0.100>p>0.05 which was not significantly different. However based on the results obtained from the history survey of venerial diseases, significance might be appeared if calculation is made on larger sample. (Table 10) 10) Smoking habit was compared between the series of patients with cancer o f the bladder and control. Smoking habit in 163 male patients with cancer of the bladder and 163 male controls were found in 92.0% and 77.3% respectively. X2-test showed significant difference between these two groups at risk of below 0.5% (x2=13.607, p<0.005). In females, smoking habit was seen in 37.9% of 29 patients with cancer of the bladder and in 13.0% of 59 controls. This figures also gave significant difference at risk of below 1% (x2=6.823, 0.005<p<0.10). Relative risks (ratio of smokers to non-smkers) for male and female patients were 3.35 and 3.8 respectively (Table 11). Furthermore, duration of the habit and amount of smoking was compared between the patients and controls . Cut and pipe tobacoo was calculated as its 1 gram is equivalent to 1 cigarett . Then calculation was made on cigarettes -a day- years, from which smoking habit was designated as the following manner. heavy smoker : over 600 cigarettes-a day-years medium smoker : between 600 and 300 cigarettes-a day-years light smoker : less than 300 cigarettes-a day-years. The results obtained from 150 male patients with cancer of the bladder demonstrated that heavy, medium and light smokers were 43.4%, 41.3% and 15.3%, respectively, which showed statistically significant difference, at risk of below 0.5%, in comparison with 126 patients of controls having heavy, medium and light smoking habits in 33.3%, 31.8% and 34.9%, respectively (x'=14.266, c6=2, p<0.005). This means that male patients with cancer of the bladder consisted of more frequent mumber of heavy and medium smokers (Table 12) . However, comparing results of studies in foreign countries, relative risk of heavy smoker is remarkably low in the male patients (Table 15). In Japan, virtually all kinds of tabacoo are provided as cigarett. Thus only 3 patients in our series used to smoke only cut tabacoo . In all Japan, the yearly amount of consumpticn of cigarett in 1963 increased about twice as much as that in 1945 (Fig. 10). These facts might concern to one of the cause of increase in prevalence of cancer of the bladder observed in Japanese population. In addition, another specificity was demonstrated on the histological pattern of the primary lesion in heavy smokers. In 42 patints who were histologically examined among 65 heavy smoking patients with cancer of the bladder, transitional cell cancer was found in 41 cases and squamous cell cancer was seen in only one case (Table 13). These data on relationship between smoking habit and cancer of the bladder have never been reported in Japan, but the problem is very important and must be studied further as seriously as the relationship between smoking and cancer of its lung.