Can Uterus Fibroids Be Cancerous and Fibroids: What to Know

September 13, 2025

Can Uterine Fibroids Be Cancerous? What to Know

Uterine fibroids (also called leiomyomas) are very common benign growths that develop in the muscular wall of the uterus. By age 50, an estimated 70–80% of women will have fibroids, though many never experience symptoms. Understandably, one of the most frequent questions is whether fibroids can become cancerous. Here’s what the best evidence from trusted sources shows, plus how fibroids are diagnosed and treated.

Are Fibroids Cancer?

Short answer: No. Fibroids are noncancerous tumors. The type of cancer people worry about in the uterus’s muscle layer is called leiomyosarcoma (LMS). Current evidence indicates leiomyosarcoma is rare and does not appear to arise from pre-existing benign fibroids; rather, it develops independently (de novo). In other words, benign fibroids do not “turn into” cancer.^1,2

How Rare Is Cancer When Fibroids Are Suspected?

Because imaging and symptoms can overlap, a key concern is the chance of discovering an unsuspected uterine sarcoma during surgery for presumed fibroids. A large evidence review commissioned by the U.S. Agency for Healthcare Research and Quality (AHRQ) estimated the risk of an occult leiomyosarcoma at approximately 1 in 770 to less than 1 in 10,000 surgeries for presumed fibroids.³ The U.S. Food and Drug Administration (FDA) cites this range and recommends careful patient selection and safeguards during certain procedures.⁴

Bottom line: The risk of a hidden cancer is very low, but not zero. That’s why preoperative evaluation and informed consent are important.

Who Gets Fibroids and What Are the Symptoms?

Fibroids can occur in anyone with a uterus, most commonly in the 30s and 40s, and tend to shrink after menopause. They are more prevalent and often more severe among Black women. Many people have no symptoms. When symptoms occur, they may include:^1,5

Heavy or prolonged menstrual bleeding, sometimes with clots
Pelvic pressure or pain, bloating, or a feeling of fullness
Frequent urination or difficulty emptying the bladder
Constipation
Pain with intercourse
Reproductive challenges (depending on size and location)

Do Certain Symptoms Suggest Cancer?

No symptom alone can diagnose leiomyosarcoma, and rapid growth is not a reliable way to distinguish benign from malignant tumors. However, any of the following warrant prompt evaluation:^1,2

Unexplained vaginal bleeding after menopause
New or rapidly worsening pelvic pain or pressure
A rapidly enlarging uterine mass, especially after menopause
Systemic symptoms like unexplained weight loss (rare)

Even when these are present, benign conditions are far more common. Definitive diagnosis of leiomyosarcoma is made by a pathologist after surgical removal; routine blood tests or biopsy of the uterine lining cannot reliably rule it out when the tumor is within the uterine muscle.²

How Are Fibroids Diagnosed?

Most fibroids are found during a pelvic exam or imaging performed for symptoms. Evaluation typically includes:^1,5

Pelvic ultrasound: First-line, widely available, and accurate for identifying fibroids.
MRI: Useful when the diagnosis is uncertain or for surgical planning; it can raise suspicion for unusual features but cannot definitively diagnose or exclude cancer.
Endometrial sampling: Recommended if there is abnormal uterine bleeding to evaluate the uterine lining (helps detect endometrial pathology, but not deeply located muscle tumors).

When Is Watchful Waiting Reasonable?

For people with mild or no symptoms, watchful waiting with periodic check-ins is appropriate. Many fibroids grow slowly, stay stable, or shrink after menopause. Monitoring is especially reasonable when childbearing is complete and symptoms are minimal.^1,5

Treatment Options for Symptomatic Fibroids

Treatment depends on symptoms, fibroid size and location, fertility goals, and overall health. Options include:^1,5,6,7

Non-surgical

NSAIDs: Help menstrual pain but do not reduce bleeding substantially.
Hormonal methods: Combined oral contraceptives or progestin-only methods may lighten bleeding.
Levonorgestrel-releasing IUD: Reduces heavy bleeding for many users.
Tranexamic acid: A non-hormonal option taken only during menses to reduce bleeding.
GnRH analogs:
- Agonists (e.g., leuprolide) can shrink fibroids temporarily; often used to improve anemia or make surgery easier.
- Antagonists such as elagolix (with estradiol/norethindrone; brand Oriahnn) and relugolix combination (Myfembree) are FDA-approved to treat heavy menstrual bleeding associated with fibroids. They reduce bleeding and fibroid size while taking them; use is time-limited due to potential bone loss, typically with “add‑back” hormones to protect bone.

Minimally invasive procedures

Uterine artery embolization (UAE): Interventional radiology procedure that blocks blood flow to fibroids, shrinking them and improving symptoms. Preserves the uterus but may affect future fertility.
Radiofrequency ablation (RFA): Laparoscopic or transcervical energy treatment that shrinks fibroids and preserves the uterus in appropriate candidates.
Hysteroscopic myomectomy: For fibroids inside the uterine cavity (submucosal), removing them through the cervix without incisions.

Surgical

Myomectomy: Surgical removal of fibroids with preservation of the uterus; preferred for those planning pregnancy. Can be hysteroscopic, laparoscopic/robotic, or open depending on size and number.
Hysterectomy: Definitive treatment that removes the uterus. Eliminates fibroids and the (already low) risk of occult sarcoma in the uterus; not suitable for those wishing to carry a pregnancy.

A Note on Power Morcellation and Cancer Safety

Some minimally invasive surgeries use devices to fragment tissue for removal (power morcellators). If an unsuspected sarcoma is present, morcellation can spread cancer cells. The FDA advises that when power morcellation is considered, it should be performed only in appropriately selected patients and within an FDA-cleared tissue containment system, after a thorough discussion of risks and alternatives.⁴

Reducing Risk and Protecting Health

Address anemia from heavy bleeding with your clinician; iron deficiency is common.
Seek evaluation for new or changing symptoms, especially after menopause.
Maintain regular preventive care. While specific lifestyle steps cannot prevent all fibroids, a healthy weight and management of blood pressure are linked to overall gynecologic health.

Key Takeaways

Uterine fibroids are benign and extremely common.
Leiomyosarcoma is rare and is not believed to develop from benign fibroids.
The chance of an unsuspected sarcoma during surgery for presumed fibroids is very low (AHRQ estimate: ~1/770 to <1/10,000).
Multiple effective treatments exist; choices depend on symptoms and reproductive goals.

This article is for general information and does not replace medical advice. If you have worrisome symptoms or are considering treatment, consult a qualified clinician.