Chronic lymphocytic leukemia (CLL) is a form of leukemia that affects white blood cells in the bone marrow and blood. These cells tend to build up slowly. Some people may not have symptoms until years after CLL develops.

In this article, we answer some of your commonly asked questions on CLL statistics and facts, including who it affects and important health information to know.

In the United States, approximately 20,700 people develop CLL each year, reports the American Cancer Society. These cases account for just over 1% of new cancer diagnoses annually. Since 2010, the frequency of CLL in the United States has been declining.

Although not very common overall, CLL is the most common form of leukemia in adults. Older adults are more likely to be affected than younger people: CLL is most frequently diagnosed in people between 65 and 74 years old. Less than 2% of new cases happen in people younger than age 45 years. CLL is rarely seen in children.

In the United States, the likelihood that the average person will get CLL is about 1 in 175, or 0.57%. The likelihood of developing CLL is higher for people who:

  • are older
  • are white
  • are male
  • have a history of exposure to certain chemicals, like Agent Orange or some pesticides
  • have radon exposure
  • have a first-degree relative with CLL

CLL is most common in non-Hispanic white males. In studies exploring the demographics of CLL in the United States, roughly 90% of cases occur in white people.

Among both males and females, the rate of new CLL cases is higher in non-Hispanic white Americans than any other racial or ethnic group.

According to the National Cancer Institute, CLL occurs at a rate of 7.8 per 100,000 white males and 4.1 per 100,000 white females. The rate in other racial and ethnic groups is:

  • non-Hispanic Black males: 4.5 per 100,000
  • non-Hispanic American Indian/Alaskan Native males: 4.3 per 100,000
  • Hispanic males: 2.6 per 100,000
  • non-Hispanic Asian/Pacific Islander males: 1.6 per 100,000
  • non-Hispanic Black females: 2.2 per 100,000
  • non-Hispanic American Indian/Alaskan Native females: 1.3 per 100,000
  • Hispanic females: 1.7 per 100,000
  • non-Hispanic Asian/Pacific Islander females: 0.8 per 100,000

These racial gaps shrink when looking at CLL death rates.

Among non-Hispanic white males, 1.8 per 100,000 people die from CLL compared with 1.3 per 100,000 in non-Hispanic Black males.

Among females, the trend is similar: 0.8 per 100,00 in non-Hispanic white females versus 0.6 per 100,000 in non-Hispanic Black females.

According to a 2022 study, Black Americans are about 64% more likely to have shorter survival with CLL than white Americans.

Researchers found the median survival in white people with CLL was 9.14 years after diagnosis compared with 7.0 years in Black people.

Differences in survival trends were not seen in any other racial group in this study, although population sizes were limited for certain groups.

Males have a slightly higher risk of getting CLL than females. Overall, the rate of CLL is 6.3 per 100,000 males and 3.3 per 100,000 females.

Compared with females, males tend to have worse outcomes of CLL over the course of the disease.

People with CLL are more likely to develop a second cancer than people without CLL. Compared with the larger U.S. population, people with CLL are 20% more likely to develop a second type of cancer independent of their CLL.

While people with CLL can get any type of second cancer besides the most common types listed above, they have an increased risk of certain ones, such as:

  • colon cancer
  • larynx cancer
  • lung cancer
  • lymphoma
  • melanoma of the skin
  • skin cancer

However, having CLL doesn’t necessarily mean you have a higher risk of all second cancers. In fact, people with a history of CLL have a decreased rate of cancer in the breasts, uterus, liver, and gallbladder and biliary ducts when compared with the larger U.S. population.

Second cancers may be the result of changes to the immune system caused by CLL, or they can be a side effect of certain types of medications used to treat CLL.

People who take fludarabine/cyclophosphamide (FC) or fludarabine/cyclophosphamide/rituximab (FCR) are most likely to have these kinds of complications, particularly AML or myelodysplastic syndromes.

Although a second cancer can happen to anyone, they’re more likely to affect:

  • adults over 60 years old
  • males
  • people with elevated blood markers

Regular cancer screening and wellness checks with your oncologist and primary care physician can help detect early signs of second cancers.

As treatment for CLL has improved, so too have survival rates. From 2012 to 2018, the 5-year relative survival rate of people with CLL compared with those without CLL was 88%.

Older data suggests more than 70% of people with CLL live for at least 10 years after diagnosis. These estimates are likely to be higher in more recent years.

In people with high risk features of CLL, including older age (over 65 years), more advanced disease, or certain molecular markers, the most common cause of death is likely to be disease progression or complications related to CLL. These types of complications typically include infection or a second cancer.

In people without these high risk features, people with CLL are about as likely to die from their cancer or a CLL-related complication as they are to die from unrelated causes.

Many people with CLL also have other health concerns, known as comorbidities. For most people with CLL, they’re no more likely to die from complications related to their CLL than any other comorbidities.

CLL is the most common form of leukemia in adults. It most often affects non-Hispanic white males over 50 years old.

People with CLL often live for long periods of time after diagnosis, but complications from the disease and treatment can happen, such as second cancers or infections.

Regular monitoring and screening with an oncologist or primary care physician can help manage CLL-related complications and improve outcomes for people with this condition.