Br. J. Cancer (1977) 35, 226
LUNG CANCER IN HONG KONG CHINESE: MORTALITY AND HISTOLOGICAL TYPES, 1960-1972 W. C. CHAN* AND R. MAcLENNANt From the *Depacrtment of Pathology, University of Hong Kong, and the tInternational Agency for Research on Cancer, Lyon, France Received 11 March 1976
Accepted 12 August 1976
Summary.-Age-adjusted mortality from lung cancer rose rapidly in both males and females in Hong Kong from 1960-1972. The relative frequency of epidermoid carcinoma increased in male bronchial biopsies but not in lung biopsies, resections, or autopsies; there was a decline in small-cell anaplastic carcinoma. In both males and females the ratio of Kreyberg Group I (epidermoid and small-cell anaplastic) to Group II (adenocarcinoma and carcinoid) tumours did not increase, despite an 80% rise in mortality from lung cancer. Adenocarcinoma was the most common type in females, despite the high mortality from lung cancer. It is speculated that cigarette smoking might produce a different pattern of histological types among Hong Kong Chinese, or that additional aetiological factors may be operating there. LUNG CANCER is now the commonest malignant neoplasm, in both males and females, in several Chinese populations. In relation to other ethnic groups, rates for Chinese females in Hong Kong (Segi, Kurihara and Matsuyama, 1969), Singapore (Shanmugaratnam, 1973) and the United States (Fraumeni and Mason, 1974) are particularly high. Such high female rates are a feature of Cantonesespeaking Chinese. Incidence rates by Chinese dialect group have been reported in Singapore, where the age-adjusted rate of 25-6 per 100,000 among Cantonese females is double that in other dialects, and is one of the highest female rates in the world (Shanmugaratnam, 1973). Over 75% of the Hong Kong population is Cantonese, and a high proportion of Chinese in the United States is also of Cantonese origin. This paper reviews the mortality from lung cancer in the period 1960-1972 for the whole of Hong Kong colony, including Kowloon, and reports on the histological types in the main pathology service for Hong Kong Island alone, during the same period.
MATERIALS AND METHODS
Mortality rates.-Deaths in Chinese in Hong Kong colony (which comprises Hong Kong Island, Kowloon and New Territories) attributed to cancers of the nasopharynx, stomach and trachea, bronchus and lung were abstracted from records of the Registrar General, Hong Kong, for the years 1949 to 1972. They were tabulated by sex and 5-year age group. Adequate population statistics date only from 1960, and consequently only deaths reported from 1960 to 1972 were analysed. From 1960 to 1968 the 7th revision of the ICD was in use in Hong Kong. This revision separates malignant neoplasms of bronchus and trachea, and of lung (henceforth termed " lung cancer ") into those specified as primary (ICD Code 162) and those unspecified as to whether primary or secondary (ICD Code 163). After 1968, the 8th revision of the ICD was in use and no longer made the distinction. In the period 1960-1968, 60-70% of lung cancers were coded as 162. Since the trends of cancers coded 162 and 163 were similar, only combined categories are reported here. Cancers of the nasopharynx and stomach were included in the analysis, to control for possible effects such as changes in
LUNG CANCER IN HONG KONG, 1960-72
227
the general level of mortality reporting. International Histopathological Reference Estimates of the mid-year population Centre for Lung Cancer was provided by for each year, 1960-1972, were provided WHO Cancer Unit. The classification was by the Census and Statistics Department, followed, but with no subtyping, the only Hong Kong, and were used for the calculation modification being the inclusion of superficial of sex/age-specific mortality rates. These squamous tumour (Type VIII) in Type I rates were then used to calculate summary (epidermoid carcinoma). An insignificant number of cases fell rates, age-standardized to a standard world outside the first 4 types of the WHO classipopulation (UICC, 1970). fication and these were grouped under the heading " others ". Several bronchial biopSources of lung tissues sies, although diagnosed as cancer, could Lung tissues for the present study were not be further typed, in addition to one from the University of Hong Kong, Depart- resected tumour (WHO-XI unclassified). ment of Pathology, located at the Queen These unclassified cases are shown in parenMary Hospital, and serving the island of thesis in the Table. Hong Kong. The tissues came from surgery Cases without histological examination (biopsies and resection) and autopsy. Bi- of the primary tumour of the lungs, were opsies of superficial lymph nodes were not excluded from the series. included. Surgery. The surgical material came RESULTS from the major sources of thoracic surgery on Hong Kong Island: 66% from the Uni- Trends in mortality versity thoracic unit in Queen Mary Hospital In Hong Kong colony during the (QMH) and Grantham Hospital, with 6% 1960 to 1972, mortality from period from Nethersole, 12% from Ruttongee and lung cancer rose from 21b7 to 39-6 in 1600 from private clinics. Bronchial biopsy was less frequently done males and from 11-4 to 19-7 in females. prior to 1964, when the University thoracic (The rates are the average annual rates unit was established. Before that date, for the years 1960-1962, and 1970-1972 most cases were resected without prior per 100,0G, age-adjusted to the standard bronchoscopy and biopsy. Patients with world population (UICC, 1970).) Thus both biopsy and resection are included in the there were ipcreases of 82.5% in males resection series. and 77.2% in females. In the same Autopsy.-The autopsy material covered period, stomach cancer rates declined in all necropsies during the period in the and females (940o and 2804% males Queen Mary Hospital, except those performe&, for medico-legal purposes. Only from 19-2 and 11U6, respectively), and one case appeared in both the surgical and carcinoma of the nasopharynx was relathe autopsy series, and has been included tively stable (up 1001% in males and in the analysis of the surgical (resection) down 82e 0 in females from 13 1 and 6-1, series. There was no previous surgical respectively). treatment or biopsy in any other autopsy This increase in mortality from lung case in the series reported. cancer in the total population of Hong Histological typing.-The original histo- Kong is reflected in our series, where logical slides of the tumours were used the total number of cases from all sources for histological tvping (by WCC). Haemayear more than doubled in males, per toxylin and eosin stained sections often and was a 400o increase in females there additional stains but occasionally sufficed, including muci-carmine, PAS and the com- (Table). bined stain for keratin and mucin-like substances (WHO, 1967) were also used. Histological types Histological typing was based on the The results of histological typing in WHO International Histological Typing of Lung Tumours (WHO, 1967). A reference our series (from Hong Kong Island) set of microscope slides assembled by the are given in the Table by source and
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LUNG CANCER IN HONG KONG CHINESE: MORTALITY AND HISTOLOGICAL TYPES, 1960-1972 W. C. CHAN* AND R. MAcLENNANt From the *Depacrtment of Pathology, University of Hong Kong, and the tInternational Agency for Research on Cancer, Lyon, France Received 11 March 1976
Accepted 12 August 1976
Summary.-Age-adjusted mortality from lung cancer rose rapidly in both males and females in Hong Kong from 1960-1972. The relative frequency of epidermoid carcinoma increased in male bronchial biopsies but not in lung biopsies, resections, or autopsies; there was a decline in small-cell anaplastic carcinoma. In both males and females the ratio of Kreyberg Group I (epidermoid and small-cell anaplastic) to Group II (adenocarcinoma and carcinoid) tumours did not increase, despite an 80% rise in mortality from lung cancer. Adenocarcinoma was the most common type in females, despite the high mortality from lung cancer. It is speculated that cigarette smoking might produce a different pattern of histological types among Hong Kong Chinese, or that additional aetiological factors may be operating there. LUNG CANCER is now the commonest malignant neoplasm, in both males and females, in several Chinese populations. In relation to other ethnic groups, rates for Chinese females in Hong Kong (Segi, Kurihara and Matsuyama, 1969), Singapore (Shanmugaratnam, 1973) and the United States (Fraumeni and Mason, 1974) are particularly high. Such high female rates are a feature of Cantonesespeaking Chinese. Incidence rates by Chinese dialect group have been reported in Singapore, where the age-adjusted rate of 25-6 per 100,000 among Cantonese females is double that in other dialects, and is one of the highest female rates in the world (Shanmugaratnam, 1973). Over 75% of the Hong Kong population is Cantonese, and a high proportion of Chinese in the United States is also of Cantonese origin. This paper reviews the mortality from lung cancer in the period 1960-1972 for the whole of Hong Kong colony, including Kowloon, and reports on the histological types in the main pathology service for Hong Kong Island alone, during the same period.
MATERIALS AND METHODS
Mortality rates.-Deaths in Chinese in Hong Kong colony (which comprises Hong Kong Island, Kowloon and New Territories) attributed to cancers of the nasopharynx, stomach and trachea, bronchus and lung were abstracted from records of the Registrar General, Hong Kong, for the years 1949 to 1972. They were tabulated by sex and 5-year age group. Adequate population statistics date only from 1960, and consequently only deaths reported from 1960 to 1972 were analysed. From 1960 to 1968 the 7th revision of the ICD was in use in Hong Kong. This revision separates malignant neoplasms of bronchus and trachea, and of lung (henceforth termed " lung cancer ") into those specified as primary (ICD Code 162) and those unspecified as to whether primary or secondary (ICD Code 163). After 1968, the 8th revision of the ICD was in use and no longer made the distinction. In the period 1960-1968, 60-70% of lung cancers were coded as 162. Since the trends of cancers coded 162 and 163 were similar, only combined categories are reported here. Cancers of the nasopharynx and stomach were included in the analysis, to control for possible effects such as changes in
LUNG CANCER IN HONG KONG, 1960-72
227
the general level of mortality reporting. International Histopathological Reference Estimates of the mid-year population Centre for Lung Cancer was provided by for each year, 1960-1972, were provided WHO Cancer Unit. The classification was by the Census and Statistics Department, followed, but with no subtyping, the only Hong Kong, and were used for the calculation modification being the inclusion of superficial of sex/age-specific mortality rates. These squamous tumour (Type VIII) in Type I rates were then used to calculate summary (epidermoid carcinoma). An insignificant number of cases fell rates, age-standardized to a standard world outside the first 4 types of the WHO classipopulation (UICC, 1970). fication and these were grouped under the heading " others ". Several bronchial biopSources of lung tissues sies, although diagnosed as cancer, could Lung tissues for the present study were not be further typed, in addition to one from the University of Hong Kong, Depart- resected tumour (WHO-XI unclassified). ment of Pathology, located at the Queen These unclassified cases are shown in parenMary Hospital, and serving the island of thesis in the Table. Hong Kong. The tissues came from surgery Cases without histological examination (biopsies and resection) and autopsy. Bi- of the primary tumour of the lungs, were opsies of superficial lymph nodes were not excluded from the series. included. Surgery. The surgical material came RESULTS from the major sources of thoracic surgery on Hong Kong Island: 66% from the Uni- Trends in mortality versity thoracic unit in Queen Mary Hospital In Hong Kong colony during the (QMH) and Grantham Hospital, with 6% 1960 to 1972, mortality from period from Nethersole, 12% from Ruttongee and lung cancer rose from 21b7 to 39-6 in 1600 from private clinics. Bronchial biopsy was less frequently done males and from 11-4 to 19-7 in females. prior to 1964, when the University thoracic (The rates are the average annual rates unit was established. Before that date, for the years 1960-1962, and 1970-1972 most cases were resected without prior per 100,0G, age-adjusted to the standard bronchoscopy and biopsy. Patients with world population (UICC, 1970).) Thus both biopsy and resection are included in the there were ipcreases of 82.5% in males resection series. and 77.2% in females. In the same Autopsy.-The autopsy material covered period, stomach cancer rates declined in all necropsies during the period in the and females (940o and 2804% males Queen Mary Hospital, except those performe&, for medico-legal purposes. Only from 19-2 and 11U6, respectively), and one case appeared in both the surgical and carcinoma of the nasopharynx was relathe autopsy series, and has been included tively stable (up 1001% in males and in the analysis of the surgical (resection) down 82e 0 in females from 13 1 and 6-1, series. There was no previous surgical respectively). treatment or biopsy in any other autopsy This increase in mortality from lung case in the series reported. cancer in the total population of Hong Histological typing.-The original histo- Kong is reflected in our series, where logical slides of the tumours were used the total number of cases from all sources for histological tvping (by WCC). Haemayear more than doubled in males, per toxylin and eosin stained sections often and was a 400o increase in females there additional stains but occasionally sufficed, including muci-carmine, PAS and the com- (Table). bined stain for keratin and mucin-like substances (WHO, 1967) were also used. Histological types Histological typing was based on the The results of histological typing in WHO International Histological Typing of Lung Tumours (WHO, 1967). A reference our series (from Hong Kong Island) set of microscope slides assembled by the are given in the Table by source and
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