Diabetes And Insulin Resistance
Diabetes mellitus is known to predispose towards a vast array of cancers. Mostly, this increased risk is due to shared risk factors such as obesity and a sedentary lifestyle. Diabetics also present with abnormally high blood sugar levels, which can promote the carcinogenic shift to glycolysis by accelerating glucose metabolism. However, those with type 2 diabetes have an increased risk of CRC even after adjusting for body mass index , physical activity, and other shared factors. Some studies have suggested that metformin, a drug that lowers blood glucose levels in diabetics, can also reduce CRC risk, although other trials have found no association. The incidence of diabetes and obesity continue to grow in the developed world, which has led many to speculate that they are the underlying factor behind the increase in CRC incidence. The population of Americans with diabetes more than doubled in the period from 1990 to 2012. The CDC estimates that 29 million Americans suffer from diabetes, and as many as 8 million of them go undiagnosed .
A recent meta-analysis of 29 prospective cohort studies in China reported a 27% higher risk of CRC associated with diabetes . In a recent Chinese prospective study of 0.5 million participants with diabetes, the adjusted HR of CRC was 1.18 . Longer duration of diabetes was associated with decreased HR .
How Common Is Colorectal Cancer
Excluding skin cancers, colorectal cancer is the third most common cancer diagnosed in the United States. The American Cancer Societys estimates for the number of colorectal cancer cases in the United States for 2022 are:
- 106,180 new cases of colon cancer
- 44,850 new cases of rectal cancer
The rate of people being diagnosed with colon or rectal cancer each year has dropped overall since the mid-1980s, mainly because more people are getting screened and changing their lifestyle-related risk factors. From 2013 to 2017, incidence rates dropped by about 1% each year. But this downward trend is mostly in older adults and masks rising incidence among younger adults since at least the mid-1990s. From 2012 through 2016, it increased every year by 2% in people younger than 50 and 1% in people 50 to 64.
Colon Cancer Statistics By Sex
- Colorectal cancer is an illness strongly influenced by sex and gender, with mortality rates in males higher than females.
- The lifetime risk of developing colorectal cancer is about 4.4% for men and 4.1% for women.
- The rate of new cases of colorectal cancer is about 38.2 per 100,000 men and women each year.
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Milk Products And Calcium
Calcium is a mineral that plays roles in muscle contraction , the secretion of hormones, sending messages through the nervous system and maintaining strong bones and teeth. There is some evidence that people who have a higher intake of calcium either from their diet or by taking supplements may have a slightly lower risk of colorectal cancer compared to those with low calcium levels. However, the reasons are not well-understood and more research is required.
Bowel Cancer Incidence By Age
Bowel cancer incidence is strongly related to age, with the highest incidence rates being in older people. In the UK in 2016-2018, on average each year more than 4 in 10 new cases were in people aged 75 and over.
Age-specific incidence rates rise steeply from around age 50-54.The highest rates are in in the 85 to 89 age group for females and males.
Incidence rates are significantly lower in females than males in a number of age groups. The gap is widest at age 65 to 69, when the age-specific incidence rate is 1.7 times lower in females than males.
Bowel cancer , Average Number of New Cases per Year and Age-Specific Incidence Rates per 100,000 Population, UK, 2016-2018
For bowel cancer, like most cancer types, incidence increases with age. The impact of routine screening on the age profile of bowel cancer is hard to discern, as bowel screening aims both to prevent and to diagnose early these effects on the incidence trend may cancel one another out. The overall increase in incidence with age largely reflects cell DNA damage accumulating over time. Damage can result from biological processes or from exposure to risk factors. A drop or plateau in incidence in the oldest age groups often indicates reduced diagnostic activity perhaps due to general ill health.
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What Are The Latest Statistics
The ACS reports that people born in 1990 have double the risk of colon cancer and quadruple the risk of rectal cancer as people born in 1950. The most recent data, which tracked the incidence of colorectal cancer from 2011 to 2016, revealed an up to 2% per year increase among people under 50. There was also a drop in the colon cancer survival rate among younger adults.
This is an alarming trend for which there are no clear explanations, says Christine Hsieh, MD, a colorectal surgeon at Keck Medicine of USC and assistant professor of clinical surgery at the Keck School of Medicine of USC.
And while 90% of colorectal cancer is found in people over the age of 50, the rise among younger adults is notable, because they are 58% more likely to be diagnosed with a later stage of the disease, when its harder to treat.
Rates By Sex Race And Ethnicity
The incidence and mortality of colorectal cancer varies by sex, race, and ethnicity . Overall, black males and females have higher incidence and mortality rates than white, American Indian and Alaska Native, and Asian and Pacific Islander males and females. Non-Hispanic males and females have higher incidence and mortality rates then Hispanic males and females.
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Get A Colonoscopy If Youre At Above
A colonoscopy is an exam where a doctor looks at the lining of the entire colon using a long, flexible tube with a tiny camera on the end.
It should be used if youre at above-average risk for getting colon cancer, meaning you have a family history of colon cancer that includes one or more parents, siblings or children with the disease. If this is the case:
- Talk to your family doctor or nurse practitioner. You are at a higher risk of colon cancer and should get checked with a colonoscopy.
- You should start getting a colonoscopy at age 50, or 10 years earlier than the age your relative was diagnosed with colon cancer, whichever comes first.
- The amount of time you should wait until getting checked again after a normal result is based on your family history. Your doctor or nurse practitioner can advise on what is appropriate for you.
Some people who have had polyps removed from their colon may be at increased risk of getting colon cancer and may need to be checked regularly with a colonoscopy instead of an at-home test.
People with inflammatory bowel disease may also be at increased risk for getting colon cancer and may need to get checked regularly with a colonoscopy instead of an at-home test.
If you do not have a family doctor or nurse practitioner, you can visit Health Connect Ontario or call 811. If you live in a First Nation community, you can contact your health centre or nursing station.
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For People At Average Risk
The COVID-19 pandemic has resulted in many elective procedures being put on hold, and this has led to a substantial decline in cancer screening. Health care facilities are providing cancer screening during the pandemic with many safety precautions in place. Learn how you can talk to your doctor and what steps you can take to plan, schedule, and get your regular cancer screenings inCancer Screening During the COVID-19 Pandemic.
The ACS recommends that people at average risk* of colorectal cancer start regular screening at age 45. This can be done either with a sensitive test that looks for signs of cancer in a persons stool , or with an exam that looks at the colon and rectum . These options are listed below.
People who are in good health and with a life expectancy of more than 10 years should continue regular colorectal cancer screening through the age of 75.
For people ages 76 through 85, the decision to be screened should be based on a persons preferences, life expectancy, overall health, and prior screening history.
People over 85 should no longer get colorectal cancer screening.
*For screening, people are considered to be at average risk if they do not have:
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What Can You Do To Reduce Your Risk
Although the root causes behind the increase in colorectal cancer among young adults remain unknown, Hsieh says its important to know your family history of colon cancer, get regular medical checkups, exercise, and avoid smoking cigarettes and drinking alcohol to excess.
Knowing that several people in your family were diagnosed with colon cancer can make a big difference in determining when to start your colorectal cancer screenings and even what type of treatment you may receive, she adds.
Another key step in reducing your risk of colorectal cancer is understanding the screening process, including when to start and what options are available.
Current ACS guidelines recommend that people at average risk of colorectal cancer begin screening at age 45.
If you have additional risk factors, like inflammatory bowel disease , polyps, a history of abdominal radiation for cancer, certain hereditary syndromes, or family history of colorectal cancer or certain polyps, you may need to be screened earlier or more often.
According to Hsieh, how to check for colon cancer doesnt necessarily mean you have to undergo a colonoscopy, which generally requires sedation stool-based tests are also available. She points out that each option offers benefits and recommends talking to your doctor about which screening may be right for you.
Doctors Are Working To Uncover Why Colon Cancer Numbers Are Increasing In People Under 50 Heres What You Need To Know About Risk Factors Symptoms And More
Colorectal cancer mortality rates have been dropping steadily for decades, as has the rate that new colorectal cancers are being diagnosed. Experts believe this is due, in part, to more and better screening options, which can help find precancerous polyps and remove them, before they turn into cancer.
But, behind this good news lurks another concerning trend: Colorectal cancer rates among people under 50 are on the rise. In fact, the American Cancer Society says that the disease has been steadily increasing over the past 30 to 50 years in younger adults. So, whats behind this uptick, and how do you know if you are at risk? Read on to learn more.
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Chemicals In The Environment
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.
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.
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 can disrupt the bodys metabolism, leading to obesity, 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.
In addition, some environmental chemicals may have harmful effects on the complex assortment of bacteria in the gut, Dr. Woychik noted.
People are exposed to many chemicals at the same time, some of which may interact in different ways, he added. So, its important to consider all of an individuals environmental exposures over the course of their life, including exposures in the womb, said Dr. Woychik. How those chemicals interact with a persons genetic and epigenetic characteristics is also important, he added.
All Cancers Combined Incidence By Age
Incidence rates are strongly related to age for all cancers combined, with the highest incidence rates being in older people. In the UK in 2016-2018, on average each year more than a third of new cases were in people aged 75 and over.
Age-specific incidence rates rise steeply from around age 55-59. The highest rates are in the 85 to 89 age group for females and males.
Incidence rates are significantly higher in females than males in the younger age groups and significantly lower in females than males in the older age groups.The gap is widest at age 40 to 44, when the age-specific incidence rate is 2.1 times higher in females than males.
All Cancers , Average Number of New Cases per Year and Age-Specific Incidence Rates per 100,000 Population, UK, 2016-2018
Children aged 0-14, and young people aged 15-24, each account for less than one per cent of all new cancer cases in the UK . Adults aged 25-49 contribute around a tenth of all new cancer cases, with almost twice as many cases in females as males in this age group. Adults aged 50-74 account for more than half of all new cancer cases, and elderly people aged 75+ account for more than a third , with slightly fewer cases in females than males in both age groups. There are more people aged 50-74 than aged 75+ in the population overall, hence the number of cancer cases is higher in 50-74s, but incidence rates are higher in 75+s.
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Colon Cancer Risk Factors
There are several possible risk factors for developing colon cancer or rectal cancer. Your lifestyle, diet, health conditions and family history can all play a role. While you cant change your genetics, it may be possible to lower your risk for developing colon cancer and rectal cancer by addressing the things you can change, such as losing weight or quitting smoking.
More Research Questions To Address
The studys results are far from the last word on this subject, researchers said. Because this was an observational study, it is not completely clear if the improved outcomes are from the screening or from the selection of patients to get screened, Dr. Mehta said.
The researchers could not account for factors that may have influenced doctors decisions on whether to suggest screening to certain patients and peoples decisions to undergo screening, he explained.
For example, because colonoscopy is invasive and the preparation can be difficult, its possible that only the older participants who were fit and healthy underwent this screening test. And that could explain the lower death rate seen in the group that was screened.
Additional studies will be needed to guide future recommendations on colorectal cancer screening in older adults, Dr. Umar said.
I hope we will reach a point where we can start to think about more sophisticated ways to help guide decisions about colorectal cancer screeningfor example, by looking at certain lifestyle factors or genetic risk factors that predispose some people to the disease, Dr. Chan said.
Studying the role that stool tests may play in screening people of all screening-eligible ages will also be important because the number of specialists in the United States available to do colonoscopies for people aged 45 to 75 is already limited, Dr. Umar said.
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What If You Get Colorectal Cancer
While every case is different, the good news is that surgery for both colon and rectal cancers can be highly successfuleven for many patients with advanced disease. While the treatment depends on the extent of the cancer, most patients will need surgery to remove the affected part of the colon. Some may need additional chemotherapy and some patients with rectal cancer may need radiation therapy, too. And some patients will need a colostomy, a procedure to connect the bowel to an opening in the abdomen for stool to pass through into a disposable bag. A colostomy may be temporary or permanent, depending on the surgery and, in some cases, the patient.
Surgery for rectal cancer is more highly specialized and intricate because of the location of rectal tumorsand the importance of preserving the ability to control bowel movements. Dr. Reddy says it’s important to choose a surgeon who has done many of these procedures.
Cancer is almost like an intruder in your house. It’s that level of threat.Philana Gydricza, clinical social worker
Many patients worry about how cancer treatment will affect their appearance and sexualityespecially if they are single and hope to have a long-term relationship in their future.
Gydricza and other social workers do their best to make sure patients like this know they will be vital after treatment. We tell them they still can be very sexy and beautiful, she says.
Why Is There An Uptick
Nobody knows for sure why colorectal cancer numbers are rising in young people. Sedentary lifestyle, overweight and obesity, smoking, heavy alcohol use, low-fiber, high-fat diets or diets high in processed meats, and other environmental factors have all been associated with the disease. Family history of colorectal cancer or polyps, and conditions such as inflammatory bowel disease are also risk factors.
When someone is diagnosed with cancer at a young age, people also suspect genetics, but experts still havent been able to use genetics to explain the surge. The most common genetic condition associated with colon cancer is Lynch Syndrome, which typically involves tumors on the right side of the colon. But thats not whats causing these cases. Yale doctors are seeing a lot of young people whose colorectal cancer seems to be happening sporadically, as opposed to being caused by a particular genetic syndrome, Dr. Reddy says.
Meanwhile, researchers have been making progress in such areas as molecular tumor profiling, which analyzes DNA and other biological characteristics of tumor tissue samples. This can help determine treatment decisions.
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