Fibroids And Uterine Cancer and Fibroids: What to Know

Fibroids and Uterine Cancer: What to Know

Uterine fibroids and uterine cancer can both cause abnormal bleeding and pelvic symptoms, which is why many people worry about how the two conditions are related. The short answer: fibroids are benign (noncancerous) growths, while uterine cancer is malignant. They are different conditions, and fibroids do not turn into uterine cancer. Below, youll find clear, evidence-based guidance on how they differ, the symptoms to watch for, and how doctors diagnose and treat each condition.

What are uterine fibroids?

Uterine fibroids (also called leiomyomas or myomas) are benign tumors that develop from the muscle of the uterus. They are very common, especially during the reproductive years. By age 50, most women will have fibroids, and they are more prevalent and often more severe among Black women. Fibroids can be as small as a seed or as large as a melon, and there may be one or many.

Common symptoms include:

  • Heavy or prolonged menstrual bleeding
  • Pelvic pressure or pain, bloating, or a full feeling
  • Frequent urination or constipation (from pressure on nearby organs)
  • Pain with sex
  • Infertility or pregnancy complications in some cases

Some people have no symptoms and discover fibroids during a routine exam or imaging.

What is uterine cancer?

Uterine cancer is a malignant tumor that starts in the uterus. Most uterine cancers are endometrial cancers (arising from the uterine lining). Much less commonly, cancer can begin in the muscle or connective tissue of the uterus; these are called uterine sarcomas (including leiomyosarcoma). Uterine sarcomas are rare, representing a small fraction of all uterine cancers.

Typical warning signs include:

  • Abnormal uterine bleeding (especially bleeding after menopause)
  • Bleeding between periods or very heavy periods
  • Pelvic pain or pressure

Endometrial cancer is usually diagnosed early because postmenopausal bleeding prompts evaluation, which improves outcomes.

Do fibroids increase the risk of uterine cancer?

No. Fibroids are noncancerous and are not believed to transform into cancer. Uterine sarcomas like leiomyosarcoma are biologically distinct and very rare. The concern about cancer usually arises when symptoms overlap or when a mass is discovered and needs characterization. In rare cases, an unsuspected uterine sarcoma can be found at surgery for presumed fibroids, which is why careful evaluation and informed surgical planning are important.

Shared symptoms and key differences

  • Bleeding patterns: Both can cause heavy or irregular bleeding. However, any bleeding after menopause is abnormal and should be evaluated promptly for possible endometrial cancer.
  • Growth over time: Fibroids often grow during the reproductive years and tend to shrink after menopause. Cancer does not follow this pattern and may progress despite menopause.
  • Pain and pressure: Both can cause pelvic discomfort, but rapid enlargement, especially after menopause, warrants urgent assessment.

Risk factors to know

Fibroids

  • Age (most common in 30s 60s)
  • Race (higher risk and severity among Black women)
  • Family history
  • Early first period, obesity, and certain lifestyle factors

Endometrial (uterine) cancer

  • Obesity and conditions with prolonged unopposed estrogen (e.g., polycystic ovary syndrome with infrequent periods)
  • Age (risk increases after menopause)
  • Use of estrogen without progesterone after menopause
  • Inherited syndromes (e.g., Lynch syndrome)
  • Diabetes, hypertension, and tamoxifen use

How doctors tell them apart

No single test can diagnose every case, but evaluation typically includes:

  • Pelvic exam to assess uterine size and tenderness.
  • Transvaginal ultrasound to visualize fibroids and measure the uterine lining; fibroids often appear as well-defined masses within or on the uterus.
  • MRI for complex cases or surgical planning; it can help characterize masses but cannot always exclude a rare sarcoma with certainty.
  • Endometrial biopsy or hysteroscopy if abnormal bleeding is present, to sample the uterine lining and rule out endometrial cancer.

Importantly, while imaging can strongly suggest fibroids, distinguishing a benign fibroid from a rare leiomyosarcoma before surgery is not always possible; pathology (examining tissue under a microscope) is definitive.

Treatment options at a glance

Fibroids

  • Watchful waiting: Appropriate if symptoms are mild and not affecting quality of life.
  • Medications for bleeding and pain: Nonsteroidal anti-inflammatory drugs (NSAIDs), tranexamic acid, combined hormonal contraceptives, or a levonorgestrel-releasing intrauterine device can reduce bleeding.
  • Hormonal therapies targeting fibroids: Gonadotropin-releasing hormone (GnRH) agonists (e.g., leuprolide) or oral GnRH antagonists with add-back therapy (e.g., relugolix combination, elagolix combination) can shrink fibroids and reduce heavy bleeding.
  • Minimally invasive procedures: Uterine artery embolization, radiofrequency ablation, or MRI-guided focused ultrasound can relieve symptoms while preserving the uterus for many patients.
  • Surgery: Myomectomy removes fibroids while preserving the uterus; hysterectomy cures fibroid symptoms by removing the uterus.

Surgical planning note: The U.S. Food and Drug Administration (FDA) advises against using laparoscopic power morcellators in many women because morcellation can spread an undiagnosed uterine cancer. If morcellation is considered, it should be performed only with FDA-cleared containment systems and in carefully selected patients after thorough counseling.

Uterine cancer

  • Endometrial cancer: Most often treated with surgery (hysterectomy with removal of fallopian tubes and ovaries), with radiation and/or chemotherapy as needed based on stage and tumor type. Selected patients with very early, low-grade disease who wish to preserve fertility may be candidates for high-dose progesterone therapy under close oncology supervision.
  • Uterine sarcoma: Managed by gynecologic oncology; treatment usually includes surgery, with consideration of chemotherapy and/or radiation depending on subtype and stage.

When to seek care

  • Bleeding between periods or soaking pads/tampons hourly for several hours
  • Bleeding after sex
  • Any vaginal bleeding after menopause
  • New or worsening pelvic pain, pressure, or rapid abdominal enlargement
  • Signs of anemia (fatigue, shortness of breath, dizziness)

If you have fibroids and your symptoms change after menopause, or if youre considering surgery, ask about how your team will evaluate for cancer risk and what surgical techniques will be used to minimize risk.

Key takeaways

  • Fibroids are common and benign; they do not turn into uterine cancer.
  • Abnormal bleeding is the most important shared symptom; postmenopausal bleeding requires prompt evaluation.
  • Imaging and endometrial biopsy help distinguish fibroids from endometrial cancer; definitive diagnosis of rare uterine sarcoma is by pathology.
  • Effective, individualized treatments exist for both fibroids and uterine cancerfrom medications to minimally invasive procedures and surgery.

Trusted sources and further reading

This article is for education and does not replace personalized medical advice. If youre experiencing symptoms, consult your clinician.

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