What Are Precancers and Precancerous Cells?

Precancerous cells, also called premalignant cells, are abnormal cells that have changes in how they look or grow. The cells are not cancer, but they show changes that raise the risk of turning into cancer over time.

A precancer is a group, mass, or clump of precancerous cells. Sometimes they are called precancerous or premalignant lesions and conditions.

Types of precancerous cells

Precancers are usually named or described based on where they are located in the body and what type of cell change they have. Two common types are dysplasia and hyperplasia.

Dysplasia

Dysplasia means cells are growing abnormally and have changes in their structure that are not yet cancerous. It can range from mild to severe, depending on how abnormal the cells are. Common places where dysplasia can develop are:

• Cervix or lower part of the uterus (cervical dysplasia and cervical intraepithelial neoplasia, or CIN)
• Colon or rectum (adenomatous polyps)
• Mouth (leukoplakia and erythroplakia)
• Skin (actinic keratosis, Bowen disease, and keratoacanthoma)

Hyperplasia

Hyperplasia means there are more cells than usual in a tissue, but the cells look normal and are not cancer. Common types of hyperplasia include:

• Breast hyperplasia
• Prostate hyperplasia
• Endometrial (uterine) hyperplasia

Is a polyp a precancer?

A polyp is an abnormal growth or bump that can form in certain tissues. Not all polyps are considered precancers. Some are harmless. Others may contain precancerous cells, such as dysplasia, or may eventually become cancer if not removed.

Common types of polyps include:

• Colon or colorectal polyps
• Stomach polyps
• Nasal (nose) polyps

How serious are precancers and precancerous cells?

Precancerous cells aren’t cancer and don’t have the ability to spread to different parts of the body like cancer cells do. But they can still be serious because they have the potential to turn into cancer if not treated or removed.

How long does it take for precancerous cells to become cancer?

This depends on the type and features of the cell. The process of becoming cancer can take many years. But early detection and treatment of precancers can prevent cancer from developing. Getting regular check-ups and recommended cancer screenings, like cervical and colorectal screening tests, helps find precancers and precancerous cell changes early so they can be removed or treated.

Do precancers always need to be removed?

While not all precancers will turn into cancer, they are warning signs. Ideally, precancers are removed when they are found or shortly after.

If precancers aren’t removed, they need to be tested and monitored regularly. Depending on the type of precancerous cells, other treatments, like topical medicines, freezing (cryotherapy), or laser therapy might be used instead of surgery.

Can precancers and precancerous cells come back?

Yes, a precancerous condition can come back. This might happen if:

• The precancerous cells were not completely removed
• Known risk factors, such as smoking, inflammation, or infection are not addressed
• Treatment for the precancers was not successful

Ongoing monitoring after being diagnosed with a precancer or precancerous condition is very important. Regular check-ups and follow-up testing can help find any sign of more or new precancerous changes. If caught early, these changes can be treated again before they turn into cancer.