Cancer survival in Africa, Asia, and Central America: a population-based study.

BACKGROUND: Population-based cancer survival data, a key indicator for monitoring progress against cancer, are not widely available from countries in Africa, Asia, and Central America. The aim of this study is to describe and discuss cancer survival in these regions. METHODS: Survival analysis was done for 341 658 patients diagnosed with various cancers from 1990 to 2001 and followed up to 2003, from 25 population-based cancer registries in 12 countries in sub-Saharan Africa (The Gambia, Uganda), Central America (Costa Rica), and Asia (China, India, Pakistan, Philippines, Saudi Arabia, Singapore, South Korea, Thailand, Turkey). 5-year age-standardised relative survival (ASRS) and observed survival by clinical extent of disease were determined. FINDINGS: For cancers in which prognosis depends on stage at diagnosis, survival was highest in China, South Korea, Singapore, and Turkey and lowest in Uganda and The Gambia. 5-year ASRS ranged from 76-82% for breast cancer, 63-79% for cervical cancer, 71-78% for bladder cancer, and 44-60% for large-bowel cancers in China, Singapore, South Korea, and Turkey. Survival did not exceed 22% for any cancer site in The Gambia; in Uganda, survival did not exceed 13% for any cancer site except breast (46%). Variations in survival correlated with early detection initiatives and level of development of health services. INTERPRETATION: The wide variation in cancer survival between regions emphasises the need for urgent investments in improving awareness, population-based cancer registration, early detection programmes, health-services infrastructure, and human resources. FUNDING: Association for International Cancer Research (AICR; St Andrews, UK), Association pour la Recherche sur le Cancer (ARC, Villejuif, France), and the Bill & Melinda Gates Foundation (Seattle, USA).

Cancer incidence trends in Thailand, 1989-2000.

Through 2004, five cancer registries in Thailand have collected data for more than ten years. Three-year cancer incidence in Thailand covering the years 1989-1997 has been regularly reported in three volumes of 'Cancer in Thailand. Since the data for the last decade of the 20th century have been collected, the trends in incidence of some cancer sites were analyzed. Data sources were registry data from Chiang Mai, Lampang, Khon Kaen, Bangkok, and Songkhla, which are representative of the four major geographic regions of Thailand. The data drawn in 2002 covered the years 1989 to 1997 for Bangkok, the other four registries drew data from 1989 to 2000. The population denominators were estimated from the two censuses in 1990 and 2000. Only cancers of the liver, lung, colon-rectum, female breast, uterine cervix, and all cancer sites were analyzed since cancers of these sites may have major public health impacts. Age-specific incidence rates of different 5-year age groups were projected through the period 2007-2009 using a linear regression model if the rates were increasing, and a log-linear model to prevent prediction of a negative rate if the rates were decreasing. During the past decade, colorectal and breast cancers showed a statistical significant increasing trend, while the trend was generally stable for cancer of other sites. The number of new cancer cases of all sites is expected to be approximately 125,000 by the year 2008, compared with 81,000 in 1999. However, the accuracy of projections depends very much on the quality of the cancer registries' data. The Bangkok registry significantly improved case ascertainment in recent years, while the Chiang Mai registry had a consistent drop in incidence of cancer at many sites. In-depth investigation of some cancer sites and age period cohort modeling are required for better understanding of cancer trends in Thailand.

Cancer incidence in Thailand, 1995-1997.

There are five population-based cancer registries in Thailand in different regions of the country. Four of them (Chiang Mai, Khon Kaen, Bangkok, and Songkhla) have been operating since 1988 and the other (Lampang) since the early 1990s. These registries have published regular 3-year cancer incidence reports since the first in 1993 for the period 1989-1991. The objective of this article is to summarize the figures of cancer incidence in Thailand during 1995-1997. The population of Thailand in 1996, at the middle of the period, was 27 million males and 27.5 million females. Information of cancer cases residing in the five provinces was collected and abstracted from different sources. Age-standardized incidence rate (ASR) of cancer in males and females was calculated for each registry and that for the whole country was estimated using the five registries as representatives for the four geographical regions of Thailand. The estimated number of new cancer cases in 1996 for the whole country was 35,539 men and 38,476 women and the ASRs were 149.2 and 125.0 per 10(5) population in men and women respectively. Cancer incidences greatly differed from region to region. Lung cancer was the commonest in Chiang Mai and Lampang in the Northern region in both sexes. The incidence of liver cancer in Khon Kaen in the Northeastern region outnumbered all the others in both sexes; cholangiocarcinoma was the major type of liver cancer. In Bangkok, lung cancer was the most important cancer in males and breast cancer was in females. Though it was lung and cervix uteri cancer that ranked the first in men and women in Songkhla, the rate of oral and pharyngeal cancer was exceptionally higher than in other registries. The geographical variability in cancer patterns in Thailand reflects exposure of the population to different risk factors unique to the different regions. In the study as a whole, there are some methodological weak points in estimating the ASRs and number of cancer cases for the whole country, but the results are the most reliable cancer statistics from Thailand at the moment. In conclusion, both a country-wide and region-specific cancer control programmes are needed for Thailand. The national one would be for the cancers common to all regions, and the provincial-level emphasis should be on cancers which are the major problems in the area.

Childhood cancer in Thailand: 1995-1997.

The incidences of childhood cancers in Thailand between 1995 and 1997 were determined from cancer registrations collected at five locations around the kingdom and compared with similar analyses performed at cancer registries in Asia, Europe and the USA. The incidence in Thailand was found to be lower than in some Asian and Western countries. Between 1988-1994 and 1995-1997, the incidence of childhood cancer rose 32.5%. As elsewhere in the world, leukemias, brain tumors and lymphomas comprised two-thirds of all childhood cancers. The age-peak for incidence was between 2 and 5 years, particularly for acute lymphoblastic leukemia. Carcinomas were rare. Several features of the cancer pattern correspond to other Asian populations, in particular the low incidence of Hodgkin s disease, Wilms tumor and Ewing s sarcoma. Neuroblastoma was more common than in neighboring Southeast Asian countries.

Geographic distribution of liver and stomach cancers in Thailand in relation to estimated dietary intake of nitrate, nitrite, and nitrosodimethylamine.

It is our working hypothesis that the high rate of the liver and gastric cancers in North and Northeast Thailand is associated with increased daily dietary intake of nitrate, nitrite, and nitrosodimethylamine (NDMA). Samples of fresh and preserved Thai foods were systematically collected and analyzed from 1988 to 1996 and from 1998 to 2005. Consumption frequencies of various food items were determined on the basis of a dietary questionnaire given to 467 adults (212 males and 255 females) from 1998 to 2005. Food consumption data for the preceding and current year were collected and intakes (day, week, and month) of nitrate, nitrite, and NDMA were calculated. The trends in liver and stomach cancer age-standardized incidence rates (ASR) in four regions of Thailand were compared with the dietary intake of nitrate, nitrite, and NDMA in those same geographic regions. Mean daily intakes of nitrate of 155.7 mg/kg, of nitrite of 7.1 mg/kg, and of NDMA of 1.08 microg/kg per day were found. Significant differences in dietary nitrate, nitrite, and NDMA intakes were seen between various Thai regions (P < 0.0001), and these corresponded to the variations in liver and stomach cancer ASR values between the regions. Dietary factors are likely to play key roles in different stages of liver and stomach carcinogenesis in Thailand.