Fibroids and Cancer: What to Know

Uterine fibroids are extraordinarily common, while uterine cancers are rare. Still, the overlap in symptoms can be confusing and worrying. This guide explains the difference between fibroids and cancer, who is at risk, how doctors evaluate symptoms, and what treatment options exist—using evidence from trusted medical sources.

Quick takeaways

• Fibroids (uterine leiomyomas) are benign growths and affect up to 70–80% of women by age 50.
• Uterine sarcomas, including leiomyosarcoma, are rare and are usually not believed to arise from typical fibroids.
• No single test can reliably rule out uterine sarcoma before surgery, but careful evaluation helps guide safe treatment.
• Most people with fibroids can be treated with medications or minimally invasive procedures; hysterectomy is definitive but not always necessary.

What are fibroids?

Fibroids are benign (noncancerous) tumors that grow from the muscle wall of the uterus. Many cause no symptoms. When they do, common issues include heavy menstrual bleeding, pelvic pressure, pain, urinary frequency, constipation, and—depending on location—fertility or pregnancy complications. Fibroids are most common during the reproductive years and often shrink after menopause.

Prevalence is high: by age 50, up to 70–80% of women will have fibroids detected by imaging or pathology, with higher rates and more severe symptoms among Black women. Sources: American College of Obstetricians and Gynecologists (ACOG); U.S. Office on Women’s Health (OASH/NIH).

Are fibroids cancer?

No—fibroids are benign. The malignant counterpart is uterine leiomyosarcoma (LMS), a type of uterine sarcoma. Uterine sarcomas are rare cancers, with an incidence in the United States of only a few cases per 100,000 women annually. Importantly, current evidence suggests LMS usually develops independently, not from preexisting benign fibroids.

What about hidden cancer found at surgery for presumed fibroids? Estimates vary, but contemporary evidence summarized by ACOG suggests an unexpected uterine sarcoma might be found in approximately 1 in 225 to 1 in 580 surgeries, and unexpected LMS in about 1 in 495 to 1 in 1,100. This is uncommon, but the risk is carefully considered when planning procedures. Sources: ACOG Committee Opinion on Morcellation; U.S. FDA safety communications.

Symptoms: When to worry

Fibroids and uterine cancers can share symptoms. Red flags don’t automatically mean cancer, but they do warrant prompt evaluation:

• Heavy menstrual bleeding (e.g., soaking a pad/tampon every 1–2 hours), prolonged periods, or bleeding between periods
• Bleeding after menopause
• Rapidly enlarging pelvic mass or new growth after menopause
• New, persistent pelvic pain or pressure
• Unexplained anemia, fatigue, or weight loss

Note: “Rapid growth” alone is not a reliable predictor of cancer, but growth after menopause and bleeding post-menopause raise more concern. Source: National Cancer Institute (NCI).

How doctors evaluate fibroids vs. cancer

Your clinician will review symptoms, medical and family history, and perform a pelvic exam. Depending on findings, evaluation may include:

• Pelvic ultrasound: First-line imaging to identify fibroids and map their size and location.
• MRI: Provides detailed characterization; certain features can raise concern but cannot definitively diagnose or exclude sarcoma.
• Endometrial sampling: If abnormal bleeding is present—especially after age 45 or postmenopause—sampling the uterine lining helps assess for endometrial pathology and sometimes detects sarcoma if it involves the lining.
• Laboratory tests: Check for anemia and other effects of heavy bleeding.

Key point: There is no blood test or imaging study that can reliably rule out uterine sarcoma before surgery. Decisions are made by weighing symptoms, imaging, age/menopausal status, and patient preferences. Sources: ACOG; NCI.

Treatment options for fibroids—and cancer safeguards

Watchful waiting

Asymptomatic fibroids often require no immediate treatment. Many shrink after menopause.

Medications

• NSAIDs (e.g., ibuprofen) for cramps and pain.
• Tranexamic acid for heavy menstrual bleeding during periods.
• Hormonal therapies: Combined birth control pills or progestin-only methods; levonorgestrel-releasing IUD can significantly reduce bleeding.
• GnRH agonists/antagonists to shrink fibroids and reduce bleeding, typically short-term: leuprolide; and FDA-approved combinations such as elagolix with add-back therapy and relugolix-estradiol-norethindrone for fibroid-related heavy bleeding. Sources: FDA; ACOG.

Procedures

• Uterine artery embolization (UAE): Minimally invasive; blocks blood flow to fibroids to shrink them.
• Radiofrequency ablation (laparoscopic or transcervical): Uses heat to shrink fibroids.
• MR-guided focused ultrasound: Noninvasive ultrasound energy to ablate fibroid tissue.
• Myomectomy: Surgical removal of fibroids while preserving the uterus; preferred for those desiring future pregnancy.
• Hysterectomy: Removal of the uterus; definitive treatment that eliminates fibroids and risk of recurrence.

When surgery is planned, surgeons balance minimally invasive approaches with safety measures that minimize any chance of spreading an unsuspected cancer. The U.S. FDA advises that if a power morcellator is considered for select patients, it should be used only with a tissue containment system and after thorough informed consent about risks and alternatives. Sources: FDA; ACOG.

Fertility and pregnancy

Fibroids—especially those that distort the uterine cavity (submucosal)—can affect fertility or increase miscarriage risk. Myomectomy may improve outcomes for some patients with cavity-distorting fibroids. Many individuals with fibroids conceive and carry healthy pregnancies. Treatment choice should factor in your reproductive goals. Source: ACOG.

Who is at higher risk?

• Fibroids: Family history, Black race, earlier menarche, obesity, and vitamin D deficiency are associated with higher risk. Pregnancy and certain hormonal contraceptives may be protective against growth in some cases. Sources: OASH/NIH.
• Uterine sarcoma: Risk increases with age (most common after menopause) and prior pelvic radiation; rare genetic syndromes (e.g., hereditary leiomyomatosis and renal cell cancer) also raise risk. Source: NCI.

When to seek medical care

• Heavy bleeding that soaks pads/tampons hourly or causes dizziness or fainting (seek urgent care).
• Bleeding after menopause.
• New or worsening pelvic pain, pressure, or a rapidly enlarging abdominal/pelvic mass.
• Trouble getting pregnant or recurrent pregnancy loss.

Bring a record of symptoms, bleeding patterns, and medications to your visit. Ask about diagnostic options, all appropriate treatments (including non-surgical choices), how each option affects fertility, and how your surgeon will mitigate the rare risk of occult cancer if you choose a procedure.

Bottom line

Fibroids are common and benign; uterine cancer is uncommon. With a thoughtful evaluation and a personalized treatment plan, most people can control symptoms and protect fertility when desired. Stay attentive to red flags like postmenopausal bleeding, and partner with a gynecologist who uses current, evidence-based safeguards.

Trusted sources and further reading

• ACOG: Uterine Fibroids – https://www.acog.org/womens-health/faqs/uterine-fibroids
• NCI: Uterine Sarcoma (patient guide) – https://www.cancer.gov/types/uterine/patient/uterine-sarcoma-treatment-pdq
• U.S. Office on Women’s Health (OASH/NIH): Uterine Fibroids – https://www.womenshealth.gov/a-z-topics/uterine-fibroids
• FDA Safety Communications on Power Morcellation – https://www.fda.gov/medical-devices/safety-communications/

This article is for general education and is not a substitute for personalized medical advice. If you have symptoms or concerns, consult a qualified healthcare professional.