Cairong Zhu

International patterns and trends in thyroid cancer incidence, 1973–2002

During the past several decades, an increasing incidence of thyroid cancer has been reported in many parts of the world. To date, no study has compared the trends in thyroid cancer incidence across continents. We examined incidence data from cancer incidence in five continents (CI5) over the 30-year period 1973–2002 from 19 populations in the Americas, Asia, Europe, and Oceania. Thyroid cancer rates have increased from 1973–1977 to 1998–2002 for most of the populations except Sweden, in which the incidence rates decreased about 18% for both males and females. The average increase was 48.0% among males and 66.7% among females. More recently, the age-adjusted international thyroid cancer incidence rates from 1998 to 2002 varied 5-fold for males and nearly 10-fold for females by geographic region. Considerable variation in thyroid cancer incidence was present for every continent but Africa, in which the incidence rates were generally low. Our analysis of published CI5 data suggests that thyroid cancer rates increased between 1973 and 2002 in most populations worldwide, and that the increase does not appear to be restricted to a particular region of the world or by the underlying rates of thyroid cancer.

A Birth Cohort Analysis of the Incidence of Papillary Thyroid Cancer in the United States, 1973–2004

BACKGROUND The incidence of papillary thyroid cancer has been reported to be increasing during the past three decades, with a 65-126% increase between 1975 and 2004. The reason for the increase is currently unknown. This study examined the incidence pattern of papillary thyroid cancer in the United States, and evaluated the components of birth cohort (defined based on year of birth), time period, and age as determinants of the observed time trend of the disease. METHODS Using the data from the National Cancer Institutes Surveillance, Epidemiology, and End Results program for 1973-2004, we conducted both univariate analysis and age-period-cohort modeling to evaluate birth cohort patterns and evaluate age, period, and cohort effects on incidence trends over time. RESULTS The increasing incidence showed a clear birth cohort pattern for both men and women. The results from age-period-cohort modeling showed that, while period effect appeared to have had an impact on the observed incidence trends, birth cohort effect may also explain part of the increasing trend in papillary thyroid carcinoma during the study period, especially among women. CONCLUSION While a period effect that is likely due to advancements in diagnostic techniques and increased medical detection of small thyroid nodules may explain some of the observed increase in the incidence, we speculate that birth cohort-related changes in environmental exposures (such as increased exposure to diagnostic X-rays and polybrominated diphenyl ethers) have also contributed to the observed increase in papillary thyroid cancer during the past decades.

Relationship of folate, vitamin B12 and methylation of insulin-like growth factor-II in maternal and cord blood

Background/Objective:One of the speculated mechanisms underlying fetal origin hypothesis of breast cancer is the possible influence of maternal environment on epigenetic regulation, such as changes in DNA methylation of the insulin-like growth factor-2 (IGF2) gene. The aim of the study is to investigate the relationship between folate, vitamin B12 and methylation of the IGF2 gene in maternal and cord blood.Subjects/Methods:We conducted a cross-sectional study to measure methylation patterns of IGF2 in promoters 2 (P2) and promoters 3 (P3).Results:The percentage of methylation in IGF2 P3 was higher in maternal blood than in cord blood (P<0.0001), whereas the methylation in P2 was higher in cord blood than in maternal blood (P=0.016). P3 methylation was correlated between maternal and cord blood (P<0.0001), but not P2 (P=0.06). The multivariate linear regression model showed that methylation patterns of both promoters in cord blood were not associated with serum folate levels in either cord or maternal blood, whereas the P3 methylation patterns were associated with serum levels of vitamin B12 in mothers blood (mean change (MC)=−0.22, P=0.0014). Methylation patterns in P2 of maternal blood were associated with serum levels of vitamin B12 in mothers blood (MC=−0.23, P=0.012), exposure to passive smoking (MC=0.46, P=0.034) and mothers weight gain during pregnancy (MC=0.23, P=0.019).Conclusions:The study suggests that environment influences methylation patterns in maternal blood, and then the maternal patterns influence the methylation status and levels of folate and vitamin B12 in cord blood.

Lymphoma survival patterns by WHO subtype in the United States, 1973-2003.

With the incidence and prevalence of lymphoid neoplasms increasing, a comparison of survival patterns by subtype may provide critical clues for improving the disease burden. We conducted a comprehensive survival analysis for 254,702 lymphoid neoplasm cases diagnosed during 1973–2003 at 17 Surveillance, Epidemiology and End Results (SEER) registries according to the World Health Organization (WHO) classification introduced in 2001. The best survival was observed for Hodgkin lymphoma among young patients, and the worst survival was observed among cases with plasma cell neoplasms, particularly plasma cell leukemia, in all racial groups. Being diagnosed at a lower stage without B-symptoms and a non-HIV/AIDS status favored survival for each type of lymphoma. Males typically had lower survival rates than females, but the opposite was observed for Burkitt lymphoma/leukemia among non-whites and multiple myeloma among non-Hispanic whites. Non-Hispanic whites typically had higher survival rates than blacks with the exception of multiple myeloma. Survival rates decline with age at diagnosis among elders, while the patterns were diverse by subtype among younger cases. The differences in lymphoma survival patterns suggest that distinct prognostic risk factors impact survival by subtype and that future research and public health interventions should address racial disparities in lymphoma survivorship.

Changing patterns of bladder cancer in the USA: evidence of heterogeneous disease.

Study Type – Disease prevalence (retrospective cohort)

Oral lesions, chronic diseases and the risk of head and neck cancer

OBJECTIVES The aim of our study is to explore the role of the history of oral lesions and chronic diseases on the risk of head and neck cancer in a Chinese population. MATERIALS AND METHODS Our case-control study included 921 head and neck cancer cases and 806 controls. We obtained medical history information by administering questionnaires to both cases and controls. We used unconditional logistic regression to estimate odds ratios for oral lesions and chronic conditions. RESULTS Oral submucous fibrosis (OR=24.24, 95% CI=7.39-79.52), oral leukoplakia (OR=4.05, 95% CI=2.44-6.71) and repetitive dental ulcers (OR=5.12, 95% CI=3.17-8.28) increased the risk of HNC. Depression was associated with HNC risk when adjusted for several covariates (OR=2.10, 95% CI=1.06-4.15), but the association was not statistically significant after adjusting for smoking and alcohol drinking (OR=1.53, 95% CI=0.72-3.25). Also, the crude OR suggested an association between diabetes and HNC risk (OR=1.51, 95% CI=1.09-2.11), but it was not significant after adjusting for confounders. CONCLUSION Our study reported on strong associations between HNC risk and oral leukoplakia, oral submucous fibrosis, which is consistent with prior research. We also observed repetitive dental ulcer to be associated with HNC risk. Future studies may focus on studying the association between depression and HNC, using medical records or psychological evaluation results to get more accurate information about depression, with careful assessment of tobacco and alcohol history.

Diet and the risk of head-and-neck cancer among never-smokers and smokers in a Chinese population

BACKGROUND Few studies have been conducted in China to investigate the association between diet and the risk of head-and-neck cancer (HNC). The aim of this study was to determine the relationship between diet and HNC risk in the Chinese population and to examine whether smoking status has any effect on the risk. METHODS Our multicenter case-control study included 921 HNC cases and 806 controls. We obtained information on the frequency of both animal- and plant-based food consumption. Unconditional logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (95%CIs). RESULTS The risk of HNC increased with more frequent consumption of processed meat and fermented foods but decreased with frequent consumption of fruits and vegetables. There was a significant increasing P for trend of 0.006 among smokers who consumed meat and an increased OR among smokers who consumed processed meat (OR 2.95, 95%CI 1.12-7.75). Protective odds ratios for vegetable consumption were observed among smokers only. We also observed protective odds ratios for higher egg consumption among never-smokers (P for trend=0.0.003). CONCLUSIONS Reduced HNC risks were observed for high fruit and vegetable intake, a finding consistent with the results of previous studies. Processed meat intake was associated with an increased risk. The role of dietary factors in HNC in the East Asian population is similar to that in European populations.

A birth cohort analysis of the incidence of ascending and descending colon cancer in the United States, 1973–2008

ObjectivesThere is evidence indicating that the trends in colorectal cancer (CRC) incidence rates in the United States differ according to CRC subsites, including for ascending cancer which has shown a different pattern from the overall trends. We investigated the time trends for ascending and descending colon cancer in the United States by race and gender to identify the specific components that may account for the incidence trends.MethodsUsing data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results program for 1973–2008, we conducted age–period–cohort modeling to evaluate birth cohort patterns and evaluate age–period–cohort effects on incidence trends of colon cancer over time.ResultsA clear birth cohort pattern was observed for both ascending and descending colon cancer, and the incidence rates of ascending colon cancer in the more recent birth cohorts were higher compared to earlier cohorts particularly for black males and females. This increase was most obvious in the younger age groups and appeared to accelerate, especially for black females. For descending colon cancer, the study suggested an increase in the birth cohort slope in the later birth cohorts for all gender and race groups, after a period of decline in earlier birth cohorts.ConclusionThe increase in incidence rates of both ascending and descending colon cancer in more recent birth cohorts for blacks suggests the need for targeted public health strategies to increase CRC screening. Further, additional etiological studies are warranted to evaluate factors responsible for the observed trends in more recent birth cohorts, including differences by subsites, race, and/or gender.

A birth cohort analysis of the incidence of adenocarcinoma of the uterine cervix in the USA.

We investigated the incidence trends for adenocarcinoma (AC) of the cervix among individuals belonging to the 20–44-year age group in the USA and compared the observed birth cohort incidence patterns with the changing patterns of exposure to potential risk factors associated with AC of the cervix, such as infection with human papillomavirus, use of diethylstilbestrol (DES), obesity, and use of oral contraceptives. Using data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results program for 1973–2010, we conducted age–period–cohort modeling to evaluate birth cohort patterns on incidence trends of AC of the cervix over time. The increase in the incidence of AC of the cervix started among those born around the mid 1940s and accelerated up until around the mid 1960s birth cohort in both whites and all races combined, regardless of the assumed period slope. There was a suggestion that the incidence rates of AC of the cervix slowed down after the 1975 birth cohort in both whites and all races combined. DES was used by millions of women in the USA as a synthetic estrogen between the years 1940 and 1971. This time period of DES use among pregnant women parallels the observed birth cohort trends in our study, whereby a notable acceleration in the incidence rates of AC of the cervix was observed among those born in the mid 1940s through the mid 1975s. Thus, our results appear to suggest that in-utero exposure to DES might be at least partly responsible for the observed incidence pattern of AC of the cervix as observed in this study.

Family history of cancer and head and neck cancer risk in a Chinese population

BACKGROUND The aim of this study was to investigate whether family history of cancer is associated with head and neck cancer risk in a Chinese population. MATERIALS AND METHODS This case-control study included 921 cases and 806 controls. Recruitment was from December 2010 to January 2015 in eight centers in East Asia. Controls were matched to cases with reference to sex, 5-year age group, ethnicity, and residence area at each of the centers. RESULTS We observed an increased risk of head and neck cancer due to first degree family history of head and neck cancer, but after adjustment for tobacco smoking, alcohol drinking and betel quid chewing the association was no longer apparent. The adjusted OR were 1.10 (95% CI=0.80-1.50) for family history of tobacco-related cancer and 0.96 (95%CI=0.75-1.24) for family history of any cancer with adjustment for tobacco, betel quid and alcohol habits. The ORs for having a first-degree relative with HNC were higher in all tobacco/ alcohol subgroups. CONCLUSIONS We did not observe a strong association between family history of head and neck cancer and head and neck cancer risk after taking into account lifestyle factors. Our study suggests that an increased risk due to family history of head and neck cancer may be due to shared risk factors. Further studies may be needed to assess the lifestyle factors of the relatives.