The Future Burden of Colorectal Cancer Among US Blacks and Whites

The Future Burden of Colorectal Cancer Among US Blacks and Whites Abstract Although overall colorectal cancer (CRC) incidence rates in the United States are declining, rates among younger persons (age < 55 years) are increasing, particularly among US whites. We assessed how these trends will impact the future burden (up to 2040) of CRC among US blacks and whites using an age-period-cohort model. Over the last four decades (1973 to 2014), CRC incidence rates for all ages (both sexes) have dropped by 6.6% and 33.9% in US blacks and whites, respectively. Yet we predict an upward turn in CRC cancer incidence rates over the next quarter century, particularly among US whites. The age-standardized rates of CRC were 55.4 and 43.2 per 100 000 among US blacks and whites in 2014, respectively, and are projected to be 49.5 and 43.1 in 2040, respectively. Future interventions are needed to reduce the striking differences in CRC incidence between blacks and whites. Declines in the incidence rates of colorectal cancer (CRC) have been observed in almost all ethnicities in the United States, largely due to an increased uptake of screening (1). Other factors, such as dietary factors and nonsteroidal anti-inflammatory drugs, may have also played a role in bringing about the observed declines in CRC (2). Delayed decreases in CRC incidence among US blacks relative to whites have been reported (3,4), partially explaining the presently higher burden of CRC in blacks. CRC incidence rates have been reported to have increased by 3.5% annually in adults younger than age 55 years over the period 1974 to 2013, with the greatest increases observed for rectal cancer in US whites (5). What remains less clear, however, is how current racial differences in these trends will affect the future burden of CRC among US blacks and US whites. Thus, in this study, we estimated the future burden of CRC among US blacks and whites until the year 2040. Due to reported differentials in trends, underlying risk factors, and screening effects, we present the results for colorectal cancer combined and separately by subsite, that is, colon and rectal cancer. Annual data on colon (C18) and rectal (C19-20) cancer cases for US blacks and whites (both categories include Hispanics) by age were obtained from the Surveillance, Epidemiology, and End Results (SEER)–9 registries for the period 1973–2014 (6). Cases and rates in men and women were combined, as overall incidence trends were similar between sexes (Supplementary Figure 1, available online). Population projections, based on the medium-fertility variant, were obtained from the United Nations 2010 Revision (7). Age-standardized incidence rates (ASRs) per 100 000 were calculated using the 2000 US standard population by five-year period of diagnosis and five-year age group. Cancer incidence was projected with NORDPRED using the statistical software R (8). The default model was used, which derives the relevant age, period, and cohort-related parameters from past observations to estimate future incidence rate by age and period. The proportion of the change in cancer cases due to changes in risk factors was calculated by subtracting the number of cases that would result from multiplying the current incidence by the estimated future population from the estimated number of future cases. The ASRs of colon and rectal cancer are observed to be lower in 2014 compared with 1973 (Figure 1), 3.7% and 32.3% for colon cancer and 13.4% and 37.0% for rectal cancer (6.6% and 33.9% for CRC) for blacks and whites, respectively. While this reflects rate declines over the last four decades, the model projects an upward turn in colon and rectal cancer incidence rates in future years. CRC rates will continue to be higher among US blacks, particularly for colon cancer. The incidence rate ratio (blacks vs whites) of CRC was 1.28 (95% CI = 1.24 to 1.31) in 2014 (ASRs; 55.4 and 43.2 per 100 000 among US blacks and whites, respectively) and is predicted to be 1.14 (95% confidence interval [CI] = 1.11 to 1.16) in 2040 (ASR = 49.4 and 43.1 per 100 000 among US blacks and whites, respectively). This is mainly related to the marked rise of CRC, especially colon cancer, among younger US white cohorts. On the other hand, increased utilization of endoscopy screening (colonoscopy or sigmoidoscopy) among blacks since the early 2000s (9) may play a role in reducing the gap between the two races in the future. Estimated and projected trends by age group (25–84 years) are presented in Supplementary Figure 2 (available online); incidence of CRC is predicted to rise steeply among younger adults of both races who are younger than age 55 years. Figure 1. View largeDownload slide Trends and projections of age-standardized colon and rectal cancer incidence rates among US blacks and whites. Data were standardized using the 2000 US Standard Population. ASR = age-standardized incidence rate. Figure 1. View largeDownload slide Trends and projections of age-standardized colon and rectal cancer incidence rates among US blacks and whites. Data were standardized using the 2000 US Standard Population. ASR = age-standardized incidence rate. Table 1 presents the estimated current and future numbers of new colon and rectal cancer cases by race, separating the impact of changing rates (those due to changes in risk factors and interventions) and changing demographics (those related to population growth and aging). The numbers of cases for colon and rectal cancer are predicted to increase substantially between 2014 and 2040 for blacks and whites as a result of both changes in risk factors and population aging and growth. Table 1. Estimated number of new cases of colorectal cancer in 2014 and 2040 by subsites among US blacks and whites Population/period  Cancer subsite   Colon  Rectum  Colorectal  US whites         Age-standardized rates (per 100 000)*, %    2014  30.1  13.1  43.2    2040  27.7  15.1  43.1   No. of cases          2014  88 023  36 921  124 944    2040  96 828  47 666  144 494   Change in cases, %  10.0  29.1  16.2   Change in cases due to population, %  46.6  30.2  41.8   Change in cases due to risk, %  –36.7  –1.17  –25.5  US blacks         Age-standardized rates (per 100 000)*, %    2014  41.1  14.2  55.4    2040  35.8  13.4  49.5   No. of cases          2014  14 605  5256  19 861    2040  20 620  7492  28 112   Change in cases, %  41.1  42.5  42.4   Change in cases due to population, %  75.0  59.5  70.9   Change in cases due to risk, %  –33.8  –17.0  –28.5  US total         Age-standardized rates (per 100 000)*, %    2014  28.2  12.2  40.7    2040  24.9  13.5  39.2   No. of cases          2014  97 919  41 575  139 494    2040  113 998  56 539  170 537   Change in cases, %  16.4  35.9  24.0   Change in cases due to population, %  58.1  40.1  52.6   Change in cases due to risk, %  –41.6  –4.1  –28.5  Population/period  Cancer subsite   Colon  Rectum  Colorectal  US whites         Age-standardized rates (per 100 000)*, %    2014  30.1  13.1  43.2    2040  27.7  15.1  43.1   No. of cases          2014  88 023  36 921  124 944    2040  96 828  47 666  144 494   Change in cases, %  10.0  29.1  16.2   Change in cases due to population, %  46.6  30.2  41.8   Change in cases due to risk, %  –36.7  –1.17  –25.5  US blacks         Age-standardized rates (per 100 000)*, %    2014  41.1  14.2  55.4    2040  35.8  13.4  49.5   No. of cases          2014  14 605  5256  19 861    2040  20 620  7492  28 112   Change in cases, %  41.1  42.5  42.4   Change in cases due to population, %  75.0  59.5  70.9   Change in cases due to risk, %  –33.8  –17.0  –28.5  US total         Age-standardized rates (per 100 000)*, %    2014  28.2  12.2  40.7    2040  24.9  13.5  39.2   No. of cases          2014  97 919  41 575  139 494    2040  113 998  56 539  170 537   Change in cases, %  16.4  35.9  24.0   Change in cases due to population, %  58.1  40.1  52.6   Change in cases due to risk, %  –41.6  –4.1  –28.5  * 2000 US Standard Population. Table 1. Estimated number of new cases of colorectal cancer in 2014 and 2040 by subsites among US blacks and whites Population/period  Cancer subsite   Colon  Rectum  Colorectal  US whites         Age-standardized rates (per 100 000)*, %    2014  30.1  13.1  43.2    2040  27.7  15.1  43.1   No. of cases          2014  88 023  36 921  124 944    2040  96 828  47 666  144 494   Change in cases, %  10.0  29.1  16.2   Change in cases due to population, %  46.6  30.2  41.8   Change in cases due to risk, %  –36.7  –1.17  –25.5  US blacks         Age-standardized rates (per 100 000)*, %    2014  41.1  14.2  55.4    2040  35.8  13.4  49.5   No. of cases          2014  14 605  5256  19 861    2040  20 620  7492  28 112   Change in cases, %  41.1  42.5  42.4   Change in cases due to population, %  75.0  59.5  70.9   Change in cases due to risk, %  –33.8  –17.0  –28.5  US total         Age-standardized rates (per 100 000)*, %    2014  28.2  12.2  40.7    2040  24.9  13.5  39.2   No. of cases          2014  97 919  41 575  139 494    2040  113 998  56 539  170 537   Change in cases, %  16.4  35.9  24.0   Change in cases due to population, %  58.1  40.1  52.6   Change in cases due to risk, %  –41.6  –4.1  –28.5  Population/period  Cancer subsite   Colon  Rectum  Colorectal  US whites         Age-standardized rates (per 100 000)*, %    2014  30.1  13.1  43.2    2040  27.7  15.1  43.1   No. of cases          2014  88 023  36 921  124 944    2040  96 828  47 666  144 494   Change in cases, %  10.0  29.1  16.2   Change in cases due to population, %  46.6  30.2  41.8   Change in cases due to risk, %  –36.7  –1.17  –25.5  US blacks         Age-standardized rates (per 100 000)*, %    2014  41.1  14.2  55.4    2040  35.8  13.4  49.5   No. of cases          2014  14 605  5256  19 861    2040  20 620  7492  28 112   Change in cases, %  41.1  42.5  42.4   Change in cases due to population, %  75.0  59.5  70.9   Change in cases due to risk, %  –33.8  –17.0  –28.5  US total         Age-standardized rates (per 100 000)*, %    2014  28.2  12.2  40.7    2040  24.9  13.5  39.2   No. of cases          2014  97 919  41 575  139 494    2040  113 998  56 539  170 537   Change in cases, %  16.4  35.9  24.0   Change in cases due to population, %  58.1  40.1  52.6   Change in cases due to risk, %  –41.6  –4.1  –28.5  * 2000 US Standard Population. In this article, we present, for the first time, projections of the future burden of CRC among blacks and whites in the United States up to 2040. Previous studies have reported on the increasing burden of the disease in young adults in the United States and other countries, which likely relates to the rise of early-onset CRC (4,5,10–12) and lifestyle factors, including an increasing prevalence of being overweight and obesity, reduced physical activity, and poor diet (13). In addition, some insights into the persisting disparities in CRC incidence between blacks and whites are documented here. Potential explanations for the observed disparities includes differences in CRC screening uptake, with poorer screening uptake reported in blacks when compared with whites among men and women older than age 50 years (14). The impact may be intensified by other factors, including health care utilization, referral rates by doctors, perceived susceptibility, and educational level, alongside the distribution of lifestyle factors—all of which have been suggested to explain disparities in the CRC burden between blacks and whites (15). The key strength of this study is the use of long-term and high-quality incidence data from the SEER registries and the well-established, empirically validated mode of analysis to predict the future burden incorporating demographic and risk factors via NORDPRED (8). Yet caution is warranted in the interpretation of our results as the trend-based predictions by definition involve uncertainty related to the assumption that incidence trends observed in the past will continue into the future (16). Furthermore, the predictions of the national incidence were made based on data from nine states, which may not be strictly representative of the entire population. The population forecasts are, by their nature, themselves predictions based on forecasts of birth and death rates, as well as levels of net immigration and emigration. Care should be employed in interpreting these results as we could not differentiate between Hispanic and non-Hispanic blacks or whites. In conclusion, we highlight persistently higher rates of CRC among US blacks relative to whites that are predicted to persist in the coming decades. Screening policies may need to be revisited to increase targeted coverage, in particular for disadvantaged groups. In addition, public health strategies need to be strengthened to reduce the burden of obesity, support more active lifestyles, and improve overall diet, and we need continued diligent monitoring of the recorded incidence rates by race presented here. Future research efforts are necessary to disentangle the clinical, social, biological, and environmental factors that contribute to black-white disparities. Finally, the challenge now is to detect the elements that have been most effective in decreasing disparities so that we can develop interventions that will continue to reduce the incidence in blacks. Note All authors declare no potential conflicts of interests. References 1 Winawer SJ, Zauber AG, Ho MN, et al.   Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup. N Engl J Med.  1993; 329 27: 1977– 1981. Google Scholar CrossRef Search ADS PubMed  2 Welch HG, Robertson DJ. Colorectal cancer on the decline - why screening can't explain it all. N Engl J Med.  2016; 374 17: 1605– 1607. http://dx.doi.org/10.1056/NEJMp1600448 Google Scholar CrossRef Search ADS PubMed  3 Colorectal Cancer Facts & Figures 2014-2016. https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/colorectal-cancer-facts-and-figures/colorectal-cancer-facts-and-figures-2014-2016.pdf. Accessed August 30, 2017. 4 Siegel RL, Miller KD, Fedewa SA, et al.   Colorectal cancer statistics, 2017. CA Cancer J Clin.  2017; 67 3: 177– 193. Google Scholar CrossRef Search ADS PubMed  5 Siegel RL, Fedewa SA, Anderson WF, et al.   Colorectal cancer incidence patterns in the United States, 1974–2013. J Natl Cancer Inst . 2017; 109 8:djw322. 6 The Surveillance, Epidemiology, and End Results (SEER) Program. SEER*Stat Database: Incidence - SEER 9 Regs Research Data. National Cancer Institute, DCCPS, Surveillance Research Program, Surveillance Systems Branch. https://seer.cancer.gov/. Accessed August 30, 2017. 7 United Nations, Department of Economics and Social Affairs, Population Division. World Population Prospects. The 2015 Revision . New York: United Nations, Department of Economics and Social Affairs, Population Division; 2015. 8 Moller B, Fekjaer H, Hakulinen T, et al.   Prediction of cancer incidence in the Nordic countries: Empirical comparison of different approaches. Stat Med.  2003; 22 17: 2751– 2766. http://dx.doi.org/10.1002/sim.1481 Google Scholar CrossRef Search ADS PubMed  9 Klabunde CN, Joseph DA, King JB, et al.   Vital signs: Colorectal cancer screening test use - United States, 2012. Morb Mortal Wkly Rep.  2013; 62 44: 881– 888. 10 Patel P, De P. Trends in colorectal cancer incidence and related lifestyle risk factors in 15-49-year-olds in Canada, 1969-2010. Cancer Epidemiol.  2016; 42: 90– 100. Google Scholar CrossRef Search ADS PubMed  11 Larsen IK, Bray F. Trends in colorectal cancer incidence in Norway 1962-2006: An interpretation of the temporal patterns by anatomic subsite. Int J Cancer.  2010; 126 3: 721– 732. http://dx.doi.org/10.1002/ijc.24839 Google Scholar CrossRef Search ADS PubMed  12 Young JP, Win AK, Rosty C, et al.   Rising incidence of early-onset colorectal cancer in Australia over two decades: Report and review. J Gastroenterol Hepatol.  2015; 30 1: 6– 13. http://dx.doi.org/10.1111/jgh.12792 Google Scholar CrossRef Search ADS PubMed  13 Correa Lima MP, Gomes-da-Silva MH. Colorectal cancer: Lifestyle and dietary factors. Nutr Hosp.  2005; 20 4: 235– 241. Google Scholar PubMed  14 Klabunde CN, Cronin KA, Breen N, et al.   Trends in colorectal cancer test use among vulnerable populations in the United States. Cancer Epidemiol Biomarkers Prev.  2011; 20 8: 1611– 1621. http://dx.doi.org/10.1158/1055-9965.EPI-11-0220 Google Scholar CrossRef Search ADS   15 Shokar NK, Carlson CA, Weller SC. Factors associated with racial/ethnic differences in colorectal cancer screening. J Am Board Fam Med.  2008; 21 5: 414– 426. http://dx.doi.org/10.3122/jabfm.2008.05.070266 Google Scholar CrossRef Search ADS PubMed  16 Bray F, Moller B. Predicting the future burden of cancer. Nat Rev Cancer.  2006; 6 1: 63– 74. http://dx.doi.org/10.1038/nrc1781 Google Scholar CrossRef Search ADS PubMed  © The Author(s) 2018. 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The Future Burden of Colorectal Cancer Among US Blacks and Whites

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Abstract

Abstract Although overall colorectal cancer (CRC) incidence rates in the United States are declining, rates among younger persons (age < 55 years) are increasing, particularly among US whites. We assessed how these trends will impact the future burden (up to 2040) of CRC among US blacks and whites using an age-period-cohort model. Over the last four decades (1973 to 2014), CRC incidence rates for all ages (both sexes) have dropped by 6.6% and 33.9% in US blacks and whites, respectively. Yet we predict an upward turn in CRC cancer incidence rates over the next quarter century, particularly among US whites. The age-standardized rates of CRC were 55.4 and 43.2 per 100 000 among US blacks and whites in 2014, respectively, and are projected to be 49.5 and 43.1 in 2040, respectively. Future interventions are needed to reduce the striking differences in CRC incidence between blacks and whites. Declines in the incidence rates of colorectal cancer (CRC) have been observed in almost all ethnicities in the United States, largely due to an increased uptake of screening (1). Other factors, such as dietary factors and nonsteroidal anti-inflammatory drugs, may have also played a role in bringing about the observed declines in CRC (2). Delayed decreases in CRC incidence among US blacks relative to whites have been reported (3,4), partially explaining the presently higher burden of CRC in blacks. CRC incidence rates have been reported to have increased by 3.5% annually in adults younger than age 55 years over the period 1974 to 2013, with the greatest increases observed for rectal cancer in US whites (5). What remains less clear, however, is how current racial differences in these trends will affect the future burden of CRC among US blacks and US whites. Thus, in this study, we estimated the future burden of CRC among US blacks and whites until the year 2040. Due to reported differentials in trends, underlying risk factors, and screening effects, we present the results for colorectal cancer combined and separately by subsite, that is, colon and rectal cancer. Annual data on colon (C18) and rectal (C19-20) cancer cases for US blacks and whites (both categories include Hispanics) by age were obtained from the Surveillance, Epidemiology, and End Results (SEER)–9 registries for the period 1973–2014 (6). Cases and rates in men and women were combined, as overall incidence trends were similar between sexes (Supplementary Figure 1, available online). Population projections, based on the medium-fertility variant, were obtained from the United Nations 2010 Revision (7). Age-standardized incidence rates (ASRs) per 100 000 were calculated using the 2000 US standard population by five-year period of diagnosis and five-year age group. Cancer incidence was projected with NORDPRED using the statistical software R (8). The default model was used, which derives the relevant age, period, and cohort-related parameters from past observations to estimate future incidence rate by age and period. The proportion of the change in cancer cases due to changes in risk factors was calculated by subtracting the number of cases that would result from multiplying the current incidence by the estimated future population from the estimated number of future cases. The ASRs of colon and rectal cancer are observed to be lower in 2014 compared with 1973 (Figure 1), 3.7% and 32.3% for colon cancer and 13.4% and 37.0% for rectal cancer (6.6% and 33.9% for CRC) for blacks and whites, respectively. While this reflects rate declines over the last four decades, the model projects an upward turn in colon and rectal cancer incidence rates in future years. CRC rates will continue to be higher among US blacks, particularly for colon cancer. The incidence rate ratio (blacks vs whites) of CRC was 1.28 (95% CI = 1.24 to 1.31) in 2014 (ASRs; 55.4 and 43.2 per 100 000 among US blacks and whites, respectively) and is predicted to be 1.14 (95% confidence interval [CI] = 1.11 to 1.16) in 2040 (ASR = 49.4 and 43.1 per 100 000 among US blacks and whites, respectively). This is mainly related to the marked rise of CRC, especially colon cancer, among younger US white cohorts. On the other hand, increased utilization of endoscopy screening (colonoscopy or sigmoidoscopy) among blacks since the early 2000s (9) may play a role in reducing the gap between the two races in the future. Estimated and projected trends by age group (25–84 years) are presented in Supplementary Figure 2 (available online); incidence of CRC is predicted to rise steeply among younger adults of both races who are younger than age 55 years. Figure 1. View largeDownload slide Trends and projections of age-standardized colon and rectal cancer incidence rates among US blacks and whites. Data were standardized using the 2000 US Standard Population. ASR = age-standardized incidence rate. Figure 1. View largeDownload slide Trends and projections of age-standardized colon and rectal cancer incidence rates among US blacks and whites. Data were standardized using the 2000 US Standard Population. ASR = age-standardized incidence rate. Table 1 presents the estimated current and future numbers of new colon and rectal cancer cases by race, separating the impact of changing rates (those due to changes in risk factors and interventions) and changing demographics (those related to population growth and aging). The numbers of cases for colon and rectal cancer are predicted to increase substantially between 2014 and 2040 for blacks and whites as a result of both changes in risk factors and population aging and growth. Table 1. Estimated number of new cases of colorectal cancer in 2014 and 2040 by subsites among US blacks and whites Population/period  Cancer subsite   Colon  Rectum  Colorectal  US whites         Age-standardized rates (per 100 000)*, %    2014  30.1  13.1  43.2    2040  27.7  15.1  43.1   No. of cases          2014  88 023  36 921  124 944    2040  96 828  47 666  144 494   Change in cases, %  10.0  29.1  16.2   Change in cases due to population, %  46.6  30.2  41.8   Change in cases due to risk, %  –36.7  –1.17  –25.5  US blacks         Age-standardized rates (per 100 000)*, %    2014  41.1  14.2  55.4    2040  35.8  13.4  49.5   No. of cases          2014  14 605  5256  19 861    2040  20 620  7492  28 112   Change in cases, %  41.1  42.5  42.4   Change in cases due to population, %  75.0  59.5  70.9   Change in cases due to risk, %  –33.8  –17.0  –28.5  US total         Age-standardized rates (per 100 000)*, %    2014  28.2  12.2  40.7    2040  24.9  13.5  39.2   No. of cases          2014  97 919  41 575  139 494    2040  113 998  56 539  170 537   Change in cases, %  16.4  35.9  24.0   Change in cases due to population, %  58.1  40.1  52.6   Change in cases due to risk, %  –41.6  –4.1  –28.5  Population/period  Cancer subsite   Colon  Rectum  Colorectal  US whites         Age-standardized rates (per 100 000)*, %    2014  30.1  13.1  43.2    2040  27.7  15.1  43.1   No. of cases          2014  88 023  36 921  124 944    2040  96 828  47 666  144 494   Change in cases, %  10.0  29.1  16.2   Change in cases due to population, %  46.6  30.2  41.8   Change in cases due to risk, %  –36.7  –1.17  –25.5  US blacks         Age-standardized rates (per 100 000)*, %    2014  41.1  14.2  55.4    2040  35.8  13.4  49.5   No. of cases          2014  14 605  5256  19 861    2040  20 620  7492  28 112   Change in cases, %  41.1  42.5  42.4   Change in cases due to population, %  75.0  59.5  70.9   Change in cases due to risk, %  –33.8  –17.0  –28.5  US total         Age-standardized rates (per 100 000)*, %    2014  28.2  12.2  40.7    2040  24.9  13.5  39.2   No. of cases          2014  97 919  41 575  139 494    2040  113 998  56 539  170 537   Change in cases, %  16.4  35.9  24.0   Change in cases due to population, %  58.1  40.1  52.6   Change in cases due to risk, %  –41.6  –4.1  –28.5  * 2000 US Standard Population. Table 1. Estimated number of new cases of colorectal cancer in 2014 and 2040 by subsites among US blacks and whites Population/period  Cancer subsite   Colon  Rectum  Colorectal  US whites         Age-standardized rates (per 100 000)*, %    2014  30.1  13.1  43.2    2040  27.7  15.1  43.1   No. of cases          2014  88 023  36 921  124 944    2040  96 828  47 666  144 494   Change in cases, %  10.0  29.1  16.2   Change in cases due to population, %  46.6  30.2  41.8   Change in cases due to risk, %  –36.7  –1.17  –25.5  US blacks         Age-standardized rates (per 100 000)*, %    2014  41.1  14.2  55.4    2040  35.8  13.4  49.5   No. of cases          2014  14 605  5256  19 861    2040  20 620  7492  28 112   Change in cases, %  41.1  42.5  42.4   Change in cases due to population, %  75.0  59.5  70.9   Change in cases due to risk, %  –33.8  –17.0  –28.5  US total         Age-standardized rates (per 100 000)*, %    2014  28.2  12.2  40.7    2040  24.9  13.5  39.2   No. of cases          2014  97 919  41 575  139 494    2040  113 998  56 539  170 537   Change in cases, %  16.4  35.9  24.0   Change in cases due to population, %  58.1  40.1  52.6   Change in cases due to risk, %  –41.6  –4.1  –28.5  Population/period  Cancer subsite   Colon  Rectum  Colorectal  US whites         Age-standardized rates (per 100 000)*, %    2014  30.1  13.1  43.2    2040  27.7  15.1  43.1   No. of cases          2014  88 023  36 921  124 944    2040  96 828  47 666  144 494   Change in cases, %  10.0  29.1  16.2   Change in cases due to population, %  46.6  30.2  41.8   Change in cases due to risk, %  –36.7  –1.17  –25.5  US blacks         Age-standardized rates (per 100 000)*, %    2014  41.1  14.2  55.4    2040  35.8  13.4  49.5   No. of cases          2014  14 605  5256  19 861    2040  20 620  7492  28 112   Change in cases, %  41.1  42.5  42.4   Change in cases due to population, %  75.0  59.5  70.9   Change in cases due to risk, %  –33.8  –17.0  –28.5  US total         Age-standardized rates (per 100 000)*, %    2014  28.2  12.2  40.7    2040  24.9  13.5  39.2   No. of cases          2014  97 919  41 575  139 494    2040  113 998  56 539  170 537   Change in cases, %  16.4  35.9  24.0   Change in cases due to population, %  58.1  40.1  52.6   Change in cases due to risk, %  –41.6  –4.1  –28.5  * 2000 US Standard Population. In this article, we present, for the first time, projections of the future burden of CRC among blacks and whites in the United States up to 2040. Previous studies have reported on the increasing burden of the disease in young adults in the United States and other countries, which likely relates to the rise of early-onset CRC (4,5,10–12) and lifestyle factors, including an increasing prevalence of being overweight and obesity, reduced physical activity, and poor diet (13). In addition, some insights into the persisting disparities in CRC incidence between blacks and whites are documented here. Potential explanations for the observed disparities includes differences in CRC screening uptake, with poorer screening uptake reported in blacks when compared with whites among men and women older than age 50 years (14). The impact may be intensified by other factors, including health care utilization, referral rates by doctors, perceived susceptibility, and educational level, alongside the distribution of lifestyle factors—all of which have been suggested to explain disparities in the CRC burden between blacks and whites (15). The key strength of this study is the use of long-term and high-quality incidence data from the SEER registries and the well-established, empirically validated mode of analysis to predict the future burden incorporating demographic and risk factors via NORDPRED (8). Yet caution is warranted in the interpretation of our results as the trend-based predictions by definition involve uncertainty related to the assumption that incidence trends observed in the past will continue into the future (16). Furthermore, the predictions of the national incidence were made based on data from nine states, which may not be strictly representative of the entire population. The population forecasts are, by their nature, themselves predictions based on forecasts of birth and death rates, as well as levels of net immigration and emigration. Care should be employed in interpreting these results as we could not differentiate between Hispanic and non-Hispanic blacks or whites. In conclusion, we highlight persistently higher rates of CRC among US blacks relative to whites that are predicted to persist in the coming decades. Screening policies may need to be revisited to increase targeted coverage, in particular for disadvantaged groups. In addition, public health strategies need to be strengthened to reduce the burden of obesity, support more active lifestyles, and improve overall diet, and we need continued diligent monitoring of the recorded incidence rates by race presented here. Future research efforts are necessary to disentangle the clinical, social, biological, and environmental factors that contribute to black-white disparities. Finally, the challenge now is to detect the elements that have been most effective in decreasing disparities so that we can develop interventions that will continue to reduce the incidence in blacks. Note All authors declare no potential conflicts of interests. References 1 Winawer SJ, Zauber AG, Ho MN, et al.   Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup. N Engl J Med.  1993; 329 27: 1977– 1981. Google Scholar CrossRef Search ADS PubMed  2 Welch HG, Robertson DJ. Colorectal cancer on the decline - why screening can't explain it all. N Engl J Med.  2016; 374 17: 1605– 1607. http://dx.doi.org/10.1056/NEJMp1600448 Google Scholar CrossRef Search ADS PubMed  3 Colorectal Cancer Facts & Figures 2014-2016. https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/colorectal-cancer-facts-and-figures/colorectal-cancer-facts-and-figures-2014-2016.pdf. Accessed August 30, 2017. 4 Siegel RL, Miller KD, Fedewa SA, et al.   Colorectal cancer statistics, 2017. CA Cancer J Clin.  2017; 67 3: 177– 193. Google Scholar CrossRef Search ADS PubMed  5 Siegel RL, Fedewa SA, Anderson WF, et al.   Colorectal cancer incidence patterns in the United States, 1974–2013. J Natl Cancer Inst . 2017; 109 8:djw322. 6 The Surveillance, Epidemiology, and End Results (SEER) Program. SEER*Stat Database: Incidence - SEER 9 Regs Research Data. National Cancer Institute, DCCPS, Surveillance Research Program, Surveillance Systems Branch. https://seer.cancer.gov/. Accessed August 30, 2017. 7 United Nations, Department of Economics and Social Affairs, Population Division. World Population Prospects. The 2015 Revision . New York: United Nations, Department of Economics and Social Affairs, Population Division; 2015. 8 Moller B, Fekjaer H, Hakulinen T, et al.   Prediction of cancer incidence in the Nordic countries: Empirical comparison of different approaches. Stat Med.  2003; 22 17: 2751– 2766. http://dx.doi.org/10.1002/sim.1481 Google Scholar CrossRef Search ADS PubMed  9 Klabunde CN, Joseph DA, King JB, et al.   Vital signs: Colorectal cancer screening test use - United States, 2012. Morb Mortal Wkly Rep.  2013; 62 44: 881– 888. 10 Patel P, De P. Trends in colorectal cancer incidence and related lifestyle risk factors in 15-49-year-olds in Canada, 1969-2010. Cancer Epidemiol.  2016; 42: 90– 100. Google Scholar CrossRef Search ADS PubMed  11 Larsen IK, Bray F. Trends in colorectal cancer incidence in Norway 1962-2006: An interpretation of the temporal patterns by anatomic subsite. Int J Cancer.  2010; 126 3: 721– 732. http://dx.doi.org/10.1002/ijc.24839 Google Scholar CrossRef Search ADS PubMed  12 Young JP, Win AK, Rosty C, et al.   Rising incidence of early-onset colorectal cancer in Australia over two decades: Report and review. J Gastroenterol Hepatol.  2015; 30 1: 6– 13. http://dx.doi.org/10.1111/jgh.12792 Google Scholar CrossRef Search ADS PubMed  13 Correa Lima MP, Gomes-da-Silva MH. Colorectal cancer: Lifestyle and dietary factors. Nutr Hosp.  2005; 20 4: 235– 241. Google Scholar PubMed  14 Klabunde CN, Cronin KA, Breen N, et al.   Trends in colorectal cancer test use among vulnerable populations in the United States. Cancer Epidemiol Biomarkers Prev.  2011; 20 8: 1611– 1621. http://dx.doi.org/10.1158/1055-9965.EPI-11-0220 Google Scholar CrossRef Search ADS   15 Shokar NK, Carlson CA, Weller SC. Factors associated with racial/ethnic differences in colorectal cancer screening. J Am Board Fam Med.  2008; 21 5: 414– 426. http://dx.doi.org/10.3122/jabfm.2008.05.070266 Google Scholar CrossRef Search ADS PubMed  16 Bray F, Moller B. Predicting the future burden of cancer. Nat Rev Cancer.  2006; 6 1: 63– 74. http://dx.doi.org/10.1038/nrc1781 Google Scholar CrossRef Search ADS PubMed  © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

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JNCI: Journal of the National Cancer InstituteOxford University Press

Published: Jan 23, 2018

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