Microplastics and Cancer: Answers to Your Questions

Published: March 7, 2025

Author: Beth Dougherty

Medically Reviewed By: Thejus Jayakrishnan, MD

In recent decades, the rates of some cancers, such as colorectal cancer, have increased in young adults under the age of 50.

A possible explanation for this rise is a parallel increase in rates of obesity and changes in diet, activity levels, and lifestyle.

However, according to Kimmie Ng, MD, MPH, director of the Young-Onset Colorectal Cancer Center at Dana-Farber, these factors do not fully explain the trend. She treats many young colon cancer patients who are not obese and maintain healthy lifestyles.

Along with other experts in the field, she suspects that environmental exposure may also play a role, especially since it has been increasing in recent decades.

Microplastics are an example of a growing presence in the environment that could be increasing cancer risk in young people.

“Microplastics are very concerning because of the increasing presence of plastics in general, in our lifestyle and in the environment,” says Ng.

What are Microplastics?

Microplastics are tiny pieces of plastic, less than 5 millimeters in diameter.

They can be invisibly small and are present in the air we breathe, the water we drink, and the food we eat.

They come from a variety of plastics used in products ranging from insecticides and pharmaceuticals to micro-beads in cosmetics, synthetic clothing, tires, and industrial materials.

Over the last 70 years, plastic production has grown exponentially and continues to rise.

How Much Are Cancer Rates Increasing Among Young People?

The increase in cancer rates among young people is extremely concerning.

According to the 2025 Cancer Facts and Figures report from the American Cancer Society, those under 50 were the only group in which cancer rates increased between 1995 and 2021.

For example, in recent years, young-onset colorectal cancer has increased by 2-3% annually. Other cancers with rising rates in young adults include breast cancer and lung cancer.

“The rate of increase in colorectal cancer is more pronounced among younger adults,” adds Ng.

“It is more pronounced among people in their twenties and higher among those in their thirties than among people in their forties or fifties.”

What Evidence is There That Microplastics May Be Linked to Cancer?

Microplastics can enter the body through the lungs while breathing, through the digestive tract when eating and drinking, and through the skin.

There are some human studies that have established links between microplastics and certain bodily processes that contribute to cancer.

There are also animal studies that further explore the cause-and-effect relationships between microplastics and body cells.

To date, microplastics have been found in human and animal tissues, for example, in the lungs, liver, placenta, and arteries.

Microplastics have also been shown to have many negative effects related to cancer, including:

They cause chronic inflammation.
They depress immune functions that fight cancer.
They affect the speed at which cells grow and divide.
They affect hormone levels, including reproductive hormones.
They affect plaque in the arteries.
They cause DNA damage.
They disrupt the balance between microbes and the mucosal lining of the intestine, exposing the cells lining it to damage.
They transport toxic contaminants with potential cancer risk.

However, says Ng, “The field is very much in its infancy. There are relatively few studies. More studies of human tissues and on the effect of microplastics on diseases like cancer are needed.”

What Research is Being Conducted to Better Understand Microplastics?

At Dana-Farber, Ng is collaborating with environmental science experts to begin to better understand the effect of microplastics on the colon and the development of colorectal cancer.

The field faces many challenges in establishing reliable and standardized methods for measuring the presence of microplastics.

Research aimed at understanding the health effects of microplastics is of vital importance for informing future policy decisions.

What Can I Do to Reduce My Risk Related to Microplastics?

There are several things you can try, for example:

Filter your water
Reduce single-use plastics and plastic utensils
Avoid food packaged in plastic
Choose natural fiber clothing
Vacuum often

Some of these tips may seem easy to apply, but in practice, reducing microplastic exposure is very difficult.

For example, access to plastic-free packaged food and exposure to higher levels of environmental microplastic contamination varies from community to community.

“I think decreasing the level and amount of plastic in our world is going to be a real challenge,” Ng notes. “To make changes at a systemic level, we really need more research.”

If I Am a Young Adult, What Else Can I Do to Reduce My Cancer Risk?

A key first step is to follow all cancer screening recommendations. Early detection and early treatment are fundamental approaches to improving cancer treatment outcomes.

Cancer screening recommendations typically do not include those under 40 or 45 because most new cases still occur in older adults.

However, it is important to pay attention to recommendations. Now that cancer rates in young people have been increasing and there is more information about disease risks, recommendations have been changing to include people from earlier ages.

Another important practice is to pay attention to your body to recognize the early warning signs. If you notice changes, see a doctor.

Examples of changes to watch out for:

In the case of colorectal cancer:
- Blood in the stool.
- Abdominal pain, pelvic pressure, or feeling bloated. This is especially common in the types of colorectal cancer seen in younger people.
- Changes in bowel habits, such as new diarrhea or constipation or thinner, pencil-like stools.
- Unexplained weight loss.
- Tiredness or shortness of breath with exertion, which could indicate anemia.
In the case of breast cancer:
- A lump in a breast detected during a self-exam.
- Any change in the size, shape, texture, or coloration of the breast.
- Abnormal nipple discharge.
In the case of lung cancer:
- A cough that does not improve.
- Persistent shortness of breath not explained by a recent illness.
- Back pain, especially between the shoulder blades, not explained by injury or asthma.
- Coughing up blood.
- Unexplained weight loss.

For more information, visit MyHealthFair.com and explore the Dana-Farber Cancer Institute booth, where you will find educational materials, patient support, and programs specially designed for our community.