{"id":26504,"date":"2020-11-05T12:00:00","date_gmt":"2020-11-05T12:00:00","guid":{"rendered":"https:\/\/www.cancer.gov\/news-events\/cancer-currents-blog\/2020\/colorectal-cancer-rising-younger-adults"},"modified":"2024-11-03T15:16:15","modified_gmt":"2024-11-03T15:16:15","slug":"why-is-colorectal-cancer-rising-rapidly-among-young-adults","status":"publish","type":"post","link":"https:\/\/ogkologos.com\/en\/why-is-colorectal-cancer-rising-rapidly-among-young-adults\/","title":{"rendered":"Why is Colorectal Cancer Rising Rapidly among Young Adults?"},"content":{"rendered":"

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Colorectal cancer is a leading cause of cancer death among people under 50 in the United States, with rates of new diagnoses still climbing in this age group.<\/p>\n

Credit: National Cancer Institute<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n

Doug Dallmann was in his early thirties when he first noticed blood in his stool. <\/p>\n

\u201cBut, since it only happened occasionally and didn\u2019t cause any pain, I didn\u2019t give it much thought and never brought it up with my doctor,\u201d he wrote in a personal account of his experience<\/a>.<\/p>\n

A few years later, when the bleeding became more frequent and intense, he decided to get it checked out. He was told that the cause was tiny rips in his intestines, which can\u2019t really be treated.<\/p>\n

\u201cI just figured it was my lot in life to live with blood in my stool, and returned to ignoring it,\u201d he wrote. <\/p>\n

But then he started feeling sharp pains in his pelvis and knew something was seriously wrong. At his annual physical, it didn\u2019t take long for his doctor to find the tumor. At just 40 years old, he was diagnosed with stage 3 rectal cancer.<\/p>\n

Unfortunately, Dallmann’s experience reflects a growing trend seen across the country. Since the 1990s, the rate of colorectal cancer (which includes cancers of the colon and rectum) has more than doubled among adults younger than 50. Not only that, but more younger people are dying from the disease.<\/p>\n

This rapid increase is especially puzzling because the rate of colorectal cancer has plummeted among older adults\u2014largely due to regular colonoscopies<\/a> and lower rates of smoking.<\/p>\n

\u201cWe don\u2019t understand a lot about the causes, the biology, or how to prevent early onset of the disease,\u201d said Phil Daschner, a program director in NCI\u2019s Division of Cancer Biology<\/a>. \u201cAnd that\u2019s important to learn more about because it may affect [approaches for] the treatment and survivorship<\/a> of early-onset colon cancer.\u201d<\/p>\n

In September, more than 400 leading scientists from academia, industry, and government, along with patient advocates, gathered online to exchange ideas and information about colorectal cancer in younger adults. The goal of the think tank, organized by NCI and the National Institute of Environmental Health Sciences (NIEHS), was to identify research priorities that address important questions about the disease.<\/p>\n

Although the participants discussed several different aspects of early-onset colorectal cancer\u2014including prevention, treatment, and survivorship\u2014identifying risk factors<\/a> and causes for colorectal cancer in younger adults emerged as the top priority.<\/p>\n

Rising Rates around the World<\/h2>\n

Nearly 18,000 people under the age of 50 will be diagnosed with colorectal cancer this year in the United States, said Rebecca Siegel, M.P.H., of the American Cancer Society. But the disease is still relatively rare, affecting far less than 1% of younger adults.<\/p>\n

Some groups have been hit by the rising trend more than others. For instance, although people of all races can develop colorectal cancer at a young age, the spike has mostly been seen among Alaska Natives, American Indians, and Whites<\/a>. <\/p>\n

However, Blacks are still more likely to get colorectal cancer at a young age than Whites, even though the gap is shrinking, said Nathan Ellis, Ph.D., of the University of Arizona Cancer Center.<\/p>\n

The United States isn\u2019t the only country facing the alarming rise in early-onset colorectal cancer, noted Jeffrey K. Lee, M.D., of Kaiser Permanente Northern California. Similar trends have also been documented in Canada, New Zealand, Australia, and some parts of Europe and Asia. In most of these places, the number of cases in younger adults started trending upward around 1995.<\/p>\n

Causes of Colorectal Cancer in Young Adults<\/h2>\n

Experts don\u2019t know what\u2019s causing the jump in colorectal cancer among young adults. But they do know some factors that raise the risk of colorectal cancer in older adults, including obesity, physical inactivity, and smoking. <\/p>\n

\u201cSome of those [risk factors] have become more common over the last 45 years, along with this rise in early-onset cases,\u201d said Daschner, who helped plan the think tank. So, it\u2019s possible that some of the same factors are responsible for the rise of early-onset disease, he noted. <\/p>\n

On the other hand, there may be a set of unique risk factors for colorectal cancer in younger adults that researchers haven\u2019t yet identified, he added.<\/p>\n

Although certain genetic conditions\u2014like Lynch syndrome<\/a> and familial adenomatous polyposis\u2014raise the risk of developing colorectal cancer at a young age, only 10% to 20% of early-onset colorectal cancers are caused by inherited factors, explained Kimmie Ng, M.D., of Dana-Farber Cancer Institute.<\/p>\n

When the incidence<\/a> of a disease changes by generation, that suggests the culprit is something in the environment, rather than something biological, Dr. Ng added, with many other meeting participants agreeing.<\/p>\n

Diet, Gut Bacteria, and Inflammation<\/h2>\n

Most of the discussions about the possible causes of early-onset disease converged on three interrelated factors: diet, bacteria in the gut, and inflammation.<\/p>\n

There\u2019s mounting evidence linking an unhealthy diet\u2014in particular, one high in processed meat and fat, and low in fruits and vegetables\u2014to early-onset colorectal cancer. <\/p>\n

Likewise, several studies have found that being overweight or obese may raise someone\u2019s chance of getting early-onset colorectal cancer. Using data from electronic health records, Nathan Berger, M.D., of Case Comprehensive Cancer Center, found that half of younger adults with colorectal cancer were overweight and 17% were obese<\/a>. <\/p>\n

Unhealthy diets have become more common in past decades, the researchers pointed out. And the number of children and adults who are overweight or obese continues to climb.<\/p>\n

In addition, Americans are spending more time sitting and less time being active. Studies have found that more TV time is also linked to a higher risk of early-onset colorectal cancer<\/a>, said Yin Cao, Sc.D., M.P.H., of Washington University in St. Louis. But it\u2019s not clear if that\u2019s because being less active can lead to being overweight. <\/p>\n

Other scientists have turned their focus to bacteria that live in the gut, also called the gut microbiome<\/a>. Certain types of bacteria have been pegged as accomplices in the growth and spread of colorectal cancer, and some may affect how well certain cancer treatments work<\/a>.<\/p>\n

In lab studies, toxins from several types of bacteria that are normally found in the human gut caused cancer in the intestines of mice, explained Cynthia Sears, M.D., an infectious disease expert from Johns Hopkins University. <\/p>\n

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Changes in the gut microbiome may be influencing the increasing rates of colorectal cancer in adults under 50.<\/p>\n

Credit: Journal of Translational Medicine. April 2017. doi: 10.1186\/s12967-017-1175-y. CC BY 4.0.<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n

Perhaps not surprisingly, gut bacteria are affected by the food and chemicals we eat, drink, and breathe. Studies have shown that diet, obesity, exercise, and some drugs (such as antibiotics) can all change the number and types of bacteria in our guts.<\/p>\n

Unhealthy diets and gut bacteria are connected in another way, too. Both can lead to inflammation\u2014the body\u2019s reaction to injury, disease, or irritation. In one study of mice, a high-fat diet triggered gut inflammation and accelerated the growth of tumors in the intestines<\/a>. <\/p>\n

As for gut bacteria, some bacterial toxins intensify inflammation, Dr. Sears noted. Studies have also shown that certain gut bacteria can recruit immune cells<\/a> that help cancer grow, as well as block immune cells that fight cancer. Inflammation can also generate harmful chemicals that can mutate DNA and promote cancer, explained Dr. Ng.<\/p>\n

In addition, certain chronic diseases, including irritable bowel syndrome<\/a>, Crohn\u2019s disease, and diabetes, can cause inflammation in the gut. Half of younger adults with colorectal cancer also have a chronic condition that can cause inflammation in the gut.<\/p>\n

The effects of these factors could start very early in life\u2014in childhood, infancy, or even in the womb\u2014noted Caitlin Murphy, Ph.D., M.P.H., of the University of Texas Southwestern Medical Center.<\/p>\n

Chemicals in the Environment<\/h2>\n

Scientists are also examining factors in the environment as potential causes of early-onset colorectal cancer. Such factors include things like air and water pollution, chemicals in soil and food, and pesticide use. <\/p>\n

The National Toxicology Program, led by NIEHS, has identified 18 chemicals that cause cancer in the intestines of mice or rats, said NIEHS Director Rick Woychik, Ph.D., who also heads the National Toxicology Program. Some of these chemicals might damage DNA, potentially leading to harmful mutations in cells of the colon and rectum. <\/p>\n

Other chemicals may have more indirect effects, pointed out Barbara Cohn, Ph.D., M.P.H. of the Public Health Institute. For example, mixtures of certain environmental chemicals (sometimes called endocrine<\/a> disrupters and obesogens) can disrupt the body\u2019s metabolism, leading to obesity<\/a>, she said. Even though some of those chemicals are now banned, their use in earlier decades could have effects later in life for people who were born back then, Dr. Cohn explained. <\/p>\n

In addition, some environmental chemicals may have harmful effects on the complex assortment of bacteria in the gut, Dr. Woychik noted. <\/p>\n

People are exposed to many chemicals at the same time, some of which may interact in different ways, he added. So, it\u2019s important to consider all of an individual\u2019s environmental exposures over the course of their life, including exposures in the womb, said Dr. Woychik. How those chemicals interact with a person\u2019s genetic and epigenetic characteristics is also important, he added.<\/p>\n

Informing Approaches for Prevention and Treatment<\/h2>\n

Defining the causes and risk factors for early-onset colorectal cancer will likely help inform approaches for prevention, screening, and treatment, Daschner said. <\/p>\n

For instance, health care professionals could recommend lifestyle changes or more frequent screening tests to people who, because of their exposures, are at higher risk of developing colorectal cancer at a young age. <\/p>\n

A few medical organizations have lowered, or are in the process of lowering, the recommend age to start colorectal cancer screening from 50 to 45<\/a>. For those younger than 45, tailoring colorectal cancer screening approaches to each person based on their risk factors (called precision screening) may improve the efficiency and cost-effectiveness of screening, said Dr. Lee. <\/p>\n

Homing in on the causes and risk factors will also help scientists uncover the underlying biology of early-onset colorectal cancer. More specifically, it can help scientists pinpoint specific molecules that drive the growth of colorectal cancer in young people. Which, in turn, could hatch new ideas for colorectal cancer screening and treatment. <\/p>\n

For example, some screening tests check for specific molecules made by colorectal cancer or polyps<\/a> (growths that could turn into cancer). Knowing which molecules are key to the growth of early-onset tumors could help researchers design screening or diagnostic tests<\/a> that are tailored for younger adults. It could also help them develop treatments that target those key molecules (an approach known as targeted therapy<\/a>). <\/p>\n

First, More Awareness<\/h2>\n

Although the coronavirus pandemic forced this long-planned think tank to be held online, it still brought together people with expertise in many different areas, Daschner said. <\/p>\n

\u201cWe hope the meeting will spur research collaborations across these different areas\u201d to make more progress, he added. To continue to promote research in this area, NCI has issued a funding opportunity for research on the causes of early-onset cancers<\/a>.<\/p>\n

But for now, many at the meeting agreed that there\u2019s an even more pressing step: spreading awareness of the early warning signs of colon cancer in younger adults.<\/p>\n

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Doug Dallmann was diagnosed with rectal cancer when he was 40 years old.<\/p>\n

Credit: Image courtesy of Doug Dallmann<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n

Both young people and doctors need to shed the notion that colorectal cancer is an \u201cold person\u2019s disease,\u201d several meeting participants stressed. People should get used to looking at their stool and noticing changes, they noted.<\/p>\n

\u201cIn retrospect, I wish I had paid more attention to the symptoms,\u201d noted Dallmann, the young man who initially ignored his symptoms and was misdiagnosed for years. That\u2019s why he continues to share his story. It\u2019s inspired several family members and friends to get screened, he said, and a few were found to have polyps.<\/p>\n

\u201cIt feels like a small repayment for the amazing outpouring of support I received from my friends, co-workers, families, my cancer support group, and those in the online cancer community who I\u2019ll likely never meet,” he said. “I hope that I can continue to pay it forward.\u201d<\/p>\n

Source<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

November 5, 2020, by NCI Staff Colorectal cancer is a leading cause of cancer death among people under 50 in the United States, with rates of new diagnoses still climbing in this age group. Credit: National Cancer Institute Doug Dallmann was in his early thirties when he first noticed blood in his stool.  \u201cBut, since […]<\/p>\n","protected":false},"author":2,"featured_media":26505,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[5137],"tags":[],"class_list":["post-26504","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-world-news"],"_links":{"self":[{"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/posts\/26504","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/comments?post=26504"}],"version-history":[{"count":1,"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/posts\/26504\/revisions"}],"predecessor-version":[{"id":44096,"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/posts\/26504\/revisions\/44096"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/media\/26505"}],"wp:attachment":[{"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/media?parent=26504"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/categories?post=26504"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ogkologos.com\/en\/wp-json\/wp\/v2\/tags?post=26504"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}