Incidence trend of nasopharyngeal carcinoma from 1987 to 2011 in Sihui County, Guangdong Province, South China: an age-period-cohort analysis / 癌症

<p><b>INTRODUCTION</b>In the past several decades, declining incidences of nasopharyngeal carcinoma (NPC) have been observed in Chinese populations in Hong Kong, Taiwan, Los Angeles, and Singapore. A previous study indicated that the incidence of NPC in Sihui County, South China remained stable until 2002, but whether age, diagnosis period, and birth cohort affect the incidence of NPC remains unknown.</p><p><b>METHODS</b>Age-standardized rates (ASRs) of NPC incidence based on the world standard population were examined in both males and females in Sihui County from 1987 to 2011. Joinpoint regression analysis was conducted to quantify the changes in incidence trends. A Poisson regression age-period-cohort model was used to assess the effects of age, diagnosis period, and birth cohort on the risk of NPC.</p><p><b>RESULTS</b>The ASRs of NPC incidence during the study period were 30.29/100,000 for males and 13.09/100,000 for females. The incidence of NPC remained stable at a non-significant average annual percent change of 0.2% for males and -1.6% for females throughout the entire period. A significantly increased estimated annual percent change of 6.8% (95% confidence interval, 0.1%-14.0%) was observed from 2003 to 2009 for males. The relative risk of NPC increased with advancing age up to 50-59 and decreased at ages >60 years. The period effect curves on NPC were nearly flat for males and females. The birth cohort effect curve for males showed an increase from the 1922 cohort to the 1957 cohort and a decrease thereafter. In females, there was an undulating increase in the relative risk from the 1922 cohort to the 1972 cohort.</p><p><b>CONCLUSIONS</b>The incidence trends for NPC remained generally stable in Sihui from 1987 to 2011, with an increase from 2003 to 2009. The relative risks of NPC increased in younger females.</p>

Secular trend analysis of lung cancer incidence in Sihui city, China between 1987 and 2011 / 癌症

<p><b>BACKGROUND</b>With industrial and econom ic development in recent decades in South China, cancer incidence may have changed due to the changing lifestyle and environment. However, the trends of lung cancer and the roles of smoking and other environmental risk factors in the development of lung cancer in rural areas of South China remain unclear. The purpose of this study was to explore the lung cancer incidence trends and the possible causes of these trends.</p><p><b>METHODS</b>Joinpoint regression analysis and the age-period-cohort (APC) model were used to analyze the lung cancer incidence trends in Sihui, Guangdong province, China between 1987 and 2011, and explore the possible causes of these trends.</p><p><b>RESULTS</b>A total of 2,397 lung cancer patients were involved in this study. A 3-fold increase in the incidence of lung cancer in both sexes was observed over the 25-year period. Joinpoint regression analysis showed that while the incidence continued to increase steadily in females during the entire period, a sharp acceleration was observed in males starting in 2005. The full APC model was selected to describe age, period, and birth cohort effects on lung cancer incidence trends in Sihui. The age cohorts in both sexes showed a continuously significant increase in the relative risk (RR) of lung cancer, with a peak in the eldest age group (80-84 years). The RR of lung cancer showed a fluctuating curve in both sexes. The birth cohorts identified an increased trend in both males and females; however, males had a plateau in the youngest cohorts who were born during 1955-1969.</p><p><b>CONCLUSIONS</b>Increasing trends of the incidence of lung cancer in Sihui were dominated by the effects of age and birth cohorts. Social aging, smoking, and environmental changes may play important roles in such trends.</p>

Estimation of cancer burden in Guangdong Province, China in 2009 / 癌症

<p><b>BACKGROUND</b>Surveying regional cancer incidence and mortality provides significant data that can assist in making health policy for local areas; however, the province- and region-based cancer burden in China is seldom reported. In this study, we estimated cancer incidence and mortality in Guangdong Province, China and presented basic information for making policies related to health resource allocation and disease control.</p><p><b>METHODS</b>A log-linear model was used to calculate the sex-, age-, and registry-specific ratios of incidence to mortality (I/M) based on cancer registry data from Guangzhou, Zhongshan, and Sihui between 2004 and 2008. The cancer incidences in 2009 were then estimated according to representative I/M ratios and the mortality records from eight death surveillance sites in Guangdong Province. The cancer incidences in each city were estimated by the corresponding sex- and age-specific incidences from cancer registries or death surveillance sites in each area. Finally, the total and region-based cancer incidences and mortalities for the entire population of Guangdong Province were summarized.</p><p><b>RESULTS</b>The estimated I/M ratios in Guangzhou (3.658), Zhongshan (2.153), and Sihui (1.527) were significantly different (P < 0.001), with an average I/M ratio of 2.446. Significant differences in the estimated I/M ratios were observed between distinct age groups and the three cancer registries. The estimated I/M ratio in females was significantly higher than that in males (2.864 vs. 2.027, P < 0.001). It was estimated that there were 163,376 new cancer cases (99,689 males and 63,687 females) in 2009; it was further estimated that 115,049 people (75,054 males and 39,995 females) died from cancer in Guangdong Province in 2009. The estimated crude and age-standardized rate of incidences (ASRI) in Guangdong Province were 231.34 and 246.87 per 100,000 males, respectively, and 156.98 and 163.57 per 100,000 females, respectively. The estimated crude and age-standardized rate of mortalities (ASRM) in Guangdong Province were 174.17 and 187.46 per 100,000 males, respectively, and 98.59 and 102.00 per 100,000 females, respectively. In comparison with the western area and the northern mountain area, higher ASRI and ASRM were recorded in the Pearl River Delta area and the eastern area in both males and females.</p><p><b>CONCLUSIONS</b>Cancer imposes a heavy disease burden, and cancer patterns are unevenly distributed throughout Guangdong Province. More health resources should be allocated to cancer control, especially in the western and northern mountain areas.</p>

Trends in the survival of patients with nasopharyngeal carcinoma between 1976 and 2005 in Sihui, China: a population-based study / 癌症

Both the incidence and mortality of nasopharyngeal carcinoma(NPC) have decreased in Hong Kong and Taiwan but not in mainland China. The goal of this study was to analyze trends in NPC patient survival between 1976 and 2005 in Sihui, an area of mainland China with a population at high risk for NPC. A total of 1,761 patients diagnosed with NPC between 1976 and 2005 according to the records of Sihui Cancer Registry were followed to the end of 2006. We determined their observed and relative survival rates and used Cox proportional hazards regression analysis to predict prognosis. Our results showed that the 5-year and 10-year observed survival rates of NPC patients in Sihui were 50.5% and 36.9%, respectively, and the median survival time was 5.1 years. The 5-year observed survival rate of NPC patients diagnosed after 2000 was 69.8%, significantly higher than that of patients diagnosed between 1976 and 1985 (42.5%; P < 0.001, relative risk = 0.28). Similarly, the 5-year relative survival rate was 84.8% between 2000 and 2005 but 51.8% between 1976 and 1985. Besides date of diagnosis, other prognostic factors included patient sex and age and NPC clinical stage and histologic type. The relative risks of death from NPC were 0.76 [95% confidence interval (CI): 0.65-0.90] for female comparing to male and 1.28 (95% CI: 1.00-1.64) for WHO type I comparing to WHO types II and III. For the eldest age group and the latest clinical stage group, the relative risks were 2.22 (95% CI: 1.73-2.84) and 3.41 (95% CI: 2.34-4.49), respectively. Our results indicate that the survival of NPC patients in Sihui has significantly increased in recent years and this increase is not influenced by patient's sex, age, histologic type, and clinical stage. A reduction in mortality rate is expected in coming years.

Comparison of incidence of nasopharyngeal carcinoma in populations with different fluctuation modes of immunoglobulin A antibody levels against Epstein-Barr virus capsid antigen / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the incidence regularity in populations with different fluctuation modes of Epstein-Barr virus (EBV) antibody levels.</p><p><b>METHODS</b>Based on the data of a NPC mass screening for nasopharyngeal carcinoma (NPC) in Jianggu town and Didou town of Sihui city, Guangdong province from 1992 to 1998, 586 subjects who were positive and retested for twice or above were divided into ascending group (114 subjects), stable or fluctuating group (313 subjects), and descending group (159 subjects) according to the fluctuation of immunoglobulin A antibody against EBV capsid antigen (VCA-IgA) level; 9889 subjects who were negative in the first test of VCA-IgA were set as control group. All the participants were followed-up till December 31, 2007. The incidence, onset time and clinical characteristics of NPC were compared among groups.</p><p><b>RESULTS</b>The 5-year cumulative detection rates of ascending, stable or fluctuating, and descending group were 3.51% (4/114), 0.64% (2/313) and 0.00% (0/159), respectively; the 5-year cumulative detection proportions were 4/4, 2/6 and 0/2, respectively. Comparing to the control group, the hazard ratio (HR) for the incidence of NPC in ascending group was highest (HR = 10.96, 95%CI: 3.91 - 30.74), followed by stable or fluctuating group (HR = 5.79, 95%CI: 2.45 - 13.69), and descending group (HR = 3.84, 95%CI: 0.92 - 16.01) which had the lowest HR.</p><p><b>CONCLUSION</b>Individuals with stable, fluctuating or ascending VCA-IgA level showed higher risk and earlier onset of NPC was found in ascending group.</p>

A survival analysis of 1761 nasopharyngeal carcinoma cases diagnosed during 1976-2005 in Sihui city in Guangdong province / 中华预防医学杂志

<p><b>OBJECTIVES</b>To analyze the survival rate of nasopharyngeal carcinoma (NPC) and to evaluate the effect of intervention in this high risk population of NPC.</p><p><b>METHODS</b>Based on the cancer and vital registry systems, the follow-up data of 1761 NPC cases were collected. The measures of survival include 5-year, 10-year survival rate and median survival duration. Cox model was used to screen the independent prognosis factors.</p><p><b>RESULTS</b>The 5-year and 10-year survival rates of NPC cases in Sihui were 50.62% and 37.01%, and the median survival duration was 5.05 years. The survival rate of NPC cases diagnosed after 1993 was 58.8%, which was higher than that of cases diagnosed before 1993 (43.3%). Other prognosis factors included gender, age, clinical stage and diagnostic hospital.</p><p><b>CONCLUSION</b>There is a significant improvement of NPC survival in Sihui. That is mainly related to the improvement of NPC treatment. However, it needs to a long time observation to see a mortality reduction of NPC.</p>