Racial Disparities In Colorectal Cancer Diagnosis And Care

Your race and ethnicity significantly affect your risk of cancer and how you receive and access care.

There are stark disparities in how minority groups access screening and treatment for colorectal cancer, the fourth most diagnosed cancer and second most deadly cancer in the US.¹ These disparities greatly affect health outcomes.

Identifying and understanding racial disparities in colorectal cancer care is key to making changes that improve access to high-quality healthcare for all, regardless of a person’s racial and ethnic background.

What is colorectal cancer?

Colorectal cancer is a type of cancer that occurs in the colon (large intestine) or rectum (the passage between the colon and anus).²

An estimated 150,000 people will receive a colorectal cancer diagnosis in the US in 2023. Of these, around 52,000 people will die from their cancer.³

Improved screening, advances in treatment, and a shift in risk factors have contributed to decreasing rates of colorectal cancer in older people. However, since the 1990s, the number of people under the age of 50 with colorectal cancer has nearly doubled.⁴

Not all populations are affected by colorectal cancer equally, and racial disparities are evident.

Early signs and symptoms of colorectal cancer

The early signs and symptoms of colorectal cancer can include the following:⁵

• Altered bowel habits

• Rectal bleeding (seeing blood in the stool)

• Diarrhea, constipation, or feeling like the bowel hasn’t completely emptied after a bowel movement

• Pain, aches, or cramps in the abdomen

• Unexplained weight loss

• Feeling like you need to have a bowel movement, but you can’t (tenesmus)⁶

• Weakness and fatigue

• Anemia (a low red blood cell count) — often one of the first signs of colorectal cancer

Colorectal cancer isn’t the only disease that can cause these symptoms. Therefore, having one or more of these symptoms doesn’t necessarily mean you have colorectal cancer. Infections, hemorrhoids, and irritable bowel syndrome (IBS) can present in a similar way.⁷ Your doctor will need to rule these out first.

However, you should still seek urgent medical attention if you experience any of the symptoms listed above, especially if you notice blood in your stool.

Many people don’t have any symptoms during the early stages of colorectal cancer.⁸ In these cases, routine screening is key to diagnosis.

Racial disparities in colorectal cancer prevalence

The current rates of colorectal cancer in the US by race and ethnicity per 100,000 people are as follows:⁹

• 52.3 male and 45.1 female American Indian and Alaska Native (AIAN) people

• 50.4 male and 37.2 female Black people

• 43.2 male and 32.5 female White people

• 39.6 male and 28.4 female Hispanic people

• 35.3 male and 25 female Asian American and Pacific Islander (AAPI) people

Despite the racial disparity in incidence narrowing for Black people over the past decade, they are still disproportionately affected by colorectal cancer.¹⁰

Meanwhile, the racial disparity in incidence has expanded for Native Americans over the past ten years.¹¹ It’s the most common cancer in Alaskan Natives, who have the highest rates worldwide.¹²

Ashkenazi Jews are also disproportionately affected. Ashkenazi people have higher rates of colorectal cancer than the general population.¹³

An adenomatous polyposis coli (APC) gene variant present in 6–8% of the Ashkenazi population is associated with doubling the colorectal cancer risk.¹⁴ ¹⁵ The high incidence rate may also be because Ashkenazi people have higher levels of mutations in cancer susceptibility genes like BRCA.¹⁶ However, this research is mixed — other evidence suggests people with BRCA mutations are not at increased risk of colorectal cancer.¹⁷

While the current colorectal cancer rates in Asian Americans are lower than in White Americans, it’s still the third-leading cause of cancer death in this population. For Korean Americans, it’s the second most common cancer.¹⁸ ¹⁹

Risk factors for colorectal cancer

Here are some of the factors that can increase your risk of developing colorectal cancer:

• Family history: Compared to someone with no family history of the disease, people with a first-degree relative with diagnosed colorectal cancer are twice as likely to develop it themselves.²⁰ The risk increases the more family members (first, second, and third-degree relatives) have the disease.

• Genetics: Around 35% of your colorectal cancer risk could come from genetics.²¹ Black people may have a higher frequency of genetic risk factors that predispose them to colorectal cancer.²²

• Obesity: It’s thought that changes in sex hormones, insulin, and fat cell signaling associated with obesity are the cause of the increased risk of colorectal cancer in obese people.²³

• Smoking: Direct and indirect exposure to cigarette smoke increases your risk of colorectal cancer.²⁴ Risk declines in people who stop smoking.

• Diet: A diet rich in red and processed meat is thought to be carcinogenic (cancer-causing) and increase the risk of colorectal cancer — although the data is conflicting.²⁵ As dietary fiber intake increases, colorectal cancer risk declines.²⁶

• Vitamin D levels: Vitamin D deficiency is thought to increase colorectal cancer risk by 31%.²⁷

• Diabetes: There is a 30% increase in colorectal cancer risk in people with diabetes.²⁸ People from minority races are disproportionately affected by diabetes, with AI/AN people having the highest incidence rate (14.5%).²⁹

• Inflammatory bowel disease (IBD): Chronic inflammation and altered immune responses increase colorectal cancer risk in those with inflammatory bowel diseases (namely ulcerative colitis and Crohn’s disease).³⁰ The risk increases with the duration and severity of IBD symptoms.

• Alcohol consumption: Moderate to heavy alcohol consumption increases colorectal cancer risk.³¹

• Physical inactivity: There is an inverse relationship between physical activity and colorectal cancer.³² Low levels of physical activity increase the risk.³³

• Age: People over the age of 65 are estimated to have a three times greater risk than those aged 50–64 and a 30 times greater risk than those aged 20–49.³⁴

• Exposure to environmental toxins: Exposure to environmental toxins (such as asbestos, organic solvents, and wood dust) increases your risk of developing colorectal cancer.³⁵

The role of early screening in colorectal cancer detection

The five-year survival rate is 90.9% for localized colorectal cancer (when there’s no indication that the cancer has spread), but only 15.6% for distant colorectal cancer (when the cancer has spread to other areas of the body).³⁶ This highlights the importance of screening.

Screening can help identify cancer in the early stages, meaning it can be treated early when the prognosis is best. It can also find polyps (abnormal growths that can become cancer), which can be removed before they become malignant.³⁷

The problem is that, in many cases, people with early-stage colorectal cancer don’t develop symptoms.³⁸ This is why routine screening is so important.

The American Cancer Society recommends that routine colorectal cancer screening should begin for people with average risk factors from the age of 45 years. This mirrors recommendations from the US Preventive Services Task Force (USPSTF).³⁹ ⁴⁰

There are several ways to screen for colorectal cancer. Medical screening options carried out by a doctor include colonoscopy, computed tomography (CT) colonography, and flexible sigmoidoscopy.

Some screening tests can be carried out by yourself, at home, with a kit. These include a fecal immunochemical test (FIT), a fecal occult blood test (gFOBT), and a stool DNA test (Cologuard). These tests involve collecting a small sample of your stool, then sending it off for testing. See a doctor for further investigation if you receive an abnormal result.

A colonoscopy is considered the gold standard screening tool for colorectal cancer, and other medical screening options are tier-one tools.⁴¹ At-home stool-based tests are considered tier-two tools. They are suitable for those who are unwilling or unable to have a colonoscopy.⁴²

Getting screened, no matter which test you choose, is crucial for diagnosing colorectal cancer and improving health outcomes. Ask your doctor about cancer screening and discuss the pros and cons of each method.

Racial disparities in screening for colorectal cancer

Despite the critical importance of screening to improve colorectal cancer outcomes, research shows that people from minority racial and ethnic backgrounds are less likely to receive screening.

For example, a 2020 literature review found strong evidence for racial disparities in screening for colorectal cancer.⁴³ It concluded that the higher incidence of colorectal cancer in Black people was primarily caused by lower screening rates.

Health insurance is just one factor that can influence your ability to access screening. Minority populations, especially those who are low-income, are more likely to be uninsured, preventing them from receiving screening.⁴⁴

Research suggests that even insured Black people are less likely to be recommended screening for colorectal cancer, despite them having a higher incidence rate.⁴⁵ This may be due to the doctor assuming that the person cannot afford care.

Furthermore, Black people are more likely to live in an area with a shortage of specialists. This can reduce the likelihood of doctors recommending screening to patients.⁴⁶ Even if they do receive screening, Black people are more likely to be screened by a doctor who has lower polyp detection rates, leading to missed diagnoses.⁴⁷

Ultimately, a patient’s trust in their primary care provider is of paramount importance if they are to undergo screening. Open communication is critical for fostering trust and encouraging participation in healthcare initiatives like screening. Unfortunately, racism and discrimination are still prevalent in the healthcare system, and many people from minority backgrounds feel distrustful of the system and their healthcare providers.⁴⁸

Racial disparities in colorectal cancer treatment

A study of adult patients with newly diagnosed stage I, II, or III colon cancer observed that patients from a minority race or ethnicity, particularly non-Hispanic Black patients, were less likely to receive surgery for their cancer.⁴⁹ The study also observed that Black participants were less likely to undergo surgery regardless of the stage at which their cancer was diagnosed.

Insurance status — Medicaid-insured or not insured — was found to reduce the likelihood of undergoing treatment for colorectal cancer. However, disparities were seen even in minority groups who were insured.

Unfortunately, the disparity in cancer treatment was found to significantly affect cancer outcomes.

A different study observed that the diagnosis-to-treatment interval is larger in racial minority groups, especially in those with a lower socioeconomic status.⁵⁰ This suggests that in these populations, there must be a prolonged time between receiving a colorectal cancer diagnosis and beginning treatment.

Racial disparities in colorectal cancer mortality

Colorectal cancer mortality is declining overall. Between 1970 and 2020, there was a 57% decrease in deaths.⁵¹ However, it’s important to recognize that this may not reflect trends in different minority groups.

In the AI/AN population, deaths from colorectal cancer have risen slightly each year since 1990.⁵² It is now the second most frequent cause of cancer death in this population.⁵³

Disparities can also be seen across narrower population segments. For instance, the mortality rate in certain racial groups has increased for people under the age of 50. However, while the rate has risen by 1.7% annually in White under 50s, Hispanic and AI/AN under 50s have seen a 3% increase in mortality.  During this period, mortality rates in Black and AAPI people declined or were stable.

Male sex is another population segment where racial disparities in colorectal cancer mortality can be seen. Compared to White men, colorectal cancer death rates are 46% higher in Native American men and 44% higher in Black men.⁵⁴ These populations have the highest colorectal cancer mortality in the US.

Other research has found that the death rate in Native Hawaiian and Pacific Islander men from colorectal cancer is 26% higher than in White men, although they have a lower risk of developing the disease.⁵⁵

What’s behind disparities in colorectal cancer care?

Research clearly shows there are racial disparities in colorectal cancer care. But what causes them?

The social determinants of health

Racial disparities in colorectal cancer risk factors, diagnosis, screening, treatment, and outcomes are influenced by the social determinants of health — the non-medical factors that influence health outcomes.

The social determinants of health are divided into five primary categories:

1. Economic stability

2. Social community

3. Education access and quality

4. Neighborhood and built environment

5. Access to quality healthcare

The prevalence of colorectal cancer is higher in areas affected negatively by the social determinants of health — in areas with, for example, more poverty, higher unemployment, poor access to healthcare, and higher exposure to industrial pollution and environmental toxins. These areas also have lower screening rates, so people are more likely to receive a later diagnosis.⁵⁶

Due to historical and ongoing discrimination, racial and ethnic minority communities in the US face higher poverty rates and financial difficulties.⁵⁷ ⁵⁸ Black people, for example, are more likely not to have health insurance (or only have Medicaid insurance), live in an area with lower educational attainment, and earn a lower income.⁵⁹

Over time, the social determinants of health impact a person’s risk of developing chronic diseases like cancer and their ability to access life-saving healthcare.

For example, people living on the poverty line may face barriers to accessing healthy foods and doing enough exercise. This increases their risk factors for chronic diseases like colorectal cancer. At the same time, environmental factors, like increased exposure to pollution, hazardous waste, or radiation, increase their risk of disease. The costs associated with disease, including lost time and earnings, keep these communities in the grip of poverty.⁶⁰

At the same time, these communities face challenges in accessing high-quality and timely healthcare. Factors like urban living, poor public transportation, and limited availability of doctors can make it more difficult to access screening and treatment.

Medical mistrust

Another factor in disparities in colorectal cancer care is medical mistrust.

Research has found that Black people are more likely to mistrust doctors and the health system compared to White people.⁶¹ This likely stems from discrimination, racial bias, and historically poor treatment of Black people in healthcare settings.⁶²

For example, unethical research practices, experimentation, and treatments being withheld have generated historical trauma in Black people.⁶³ As a result, it can be challenging for the healthcare provider to build rapport with their patients. Medical mistrust is believed to play a role in the low rates of cancer screening among Black people.⁶⁴

Underrepresentation in clinical trials

It’s important to have adequate representation of minority populations in clinical trials because of potential biological differences in responses to treatment.⁶⁵

Research has found that minority racial groups are underrepresented in clinical trials for colorectal cancer.⁶⁶ Clinical trial participants tend to be middle-aged White people who do not represent the unique needs and challenges faced by minority groups with a high cancer burden.⁶⁷

Several factors contribute to the underrepresentation of minority groups in clinical trials. One factor is poor access to screening, leading to later diagnoses.⁶⁸ This may cause patients to be excluded from clinical trials, since late diagnosis is associated with worse outcomes and poor trial performance.

Social determinants of health are also important to consider. For instance, structural barriers to accessing clinical trial facilities, difficulty getting time off work, low health literacy, less awareness of clinical trials, and lack of a support network may further explain why minority racial groups have lower engagement in clinical trials.⁶⁹

Medical mistrust is another factor. People from minority populations may not enroll in clinical trials partly due to the fear that they will be discriminated against by insurance companies for being identified as “high risk.”⁷⁰

What can be done to provide equitable colorectal cancer care?

Here are just some of the steps that can be taken to remove racial disparities from colorectal cancer care and improve health outcomes:⁷¹

• Nurturing patient–doctor relationships to combat medical mistrust

• Developing an equitable care delivery model that addresses socioeconomic factors to open up care for all

• Educating people from minority groups about the importance of early screening

• Ensuring minorities are represented in clinical trials to address the current lack of diversity and develop new treatments suitable for everyone, no matter their race or ethnicity

• Encourage diversity in the healthcare profession so that people from minority races feel more comfortable when accessing care and treatment

• Educating health professionals about institutional racism and the barriers minorities face when accessing high-quality healthcare

The lowdown

Colorectal cancer is a global problem, but it disproportionately affects minority groups. People from minority races, particularly Black and AI/AN people, develop colorectal cancer more often and earlier in life. They typically have worse outcomes than White people.

Moving forward, systemic change is needed to help achieve health equity. This may involve improving access to healthcare, enabling earlier screening and follow-up appointments, and making clinical trials more available to minority groups.

Having an awareness of colorectal cancer risk factors and access to routine screening helps identify cancer when the prognosis is best and the disease is most treatable.