Is Endometriosis Cancer and Fibroids: What to Know

Is Endometriosis Cancer and Fibroids: What to Know

Endometriosis and uterine fibroids are two of the most common gynecologic conditions, and both can significantly affect quality of life. People often ask whether either condition is a form of cancer—or whether having them raises cancer risk. Here’s what you should know, based on guidance from trusted sources such as the National Institutes of Health (NIH), National Cancer Institute (NCI), Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists (ACOG), and the U.S. Food and Drug Administration (FDA).

Quick answer: Are endometriosis or fibroids cancer?

  • Endometriosis is not cancer. It occurs when tissue similar to the uterine lining grows outside the uterus, causing inflammation and pain. While endometriosis is not malignant, it is associated with a small increase in risk for certain ovarian cancers. Overall risk remains low for most people (NCI).
  • Fibroids are not cancer. Uterine fibroids (leiomyomas) are benign growths of the muscle wall of the uterus. They do not turn into cancer. Very rarely, a different cancer called uterine sarcoma can be present, but this is uncommon (ACOG).

Understanding the conditions

What is endometriosis?

Endometriosis involves endometrium-like tissue growing outside the uterus—on the ovaries, fallopian tubes, pelvic lining, and occasionally beyond. It commonly causes pelvic pain that can be severe, especially around menstruation, and may be linked with infertility (NIH MedlinePlus; ACOG).

What are uterine fibroids?

Fibroids are noncancerous tumors made of smooth muscle and connective tissue that develop in the uterine wall. They are extremely common, particularly during the reproductive years. Many cause no symptoms; others lead to heavy menstrual bleeding, pelvic pressure, frequent urination, constipation, pain with intercourse, and pregnancy or fertility issues (CDC; NIH MedlinePlus).

How are they related to cancer?

Endometriosis and cancer risk

  • Not cancerous: Endometriosis lesions are benign.
  • Slightly higher ovarian cancer risk: People with endometriosis have a modestly increased risk of certain ovarian cancers (notably endometrioid and clear cell subtypes). Importantly, the absolute risk remains low—most people with endometriosis will never develop ovarian cancer (NCI).
  • No proven screening test: There is no effective population screening test for ovarian cancer. Discuss individual risk and symptom awareness with your clinician.

Fibroids and cancer risk

  • Benign by nature: Fibroids do not become cancer. Having fibroids does not meaningfully increase your risk of uterine cancer.
  • Rare sarcoma: A different, rare cancer called uterine sarcoma (e.g., leiomyosarcoma) can occur independently and may sometimes be mistaken for a fibroid before surgery. This is uncommon, and fibroids themselves do not transform into sarcoma (ACOG).

Symptoms: How they overlap and differ

  • Shared symptoms: Heavy menstrual bleeding, pelvic pain, and fertility challenges can occur in both conditions.
  • More typical of endometriosis: Severe period pain, pain with intercourse, pain with bowel movements during menses, and chronic pelvic pain that flares cyclically.
  • More typical of fibroids: Heavy or prolonged periods, anemia, a sensation of pelvic pressure or fullness, frequent urination, constipation, and an enlarged abdomen.

Diagnosis

  • Endometriosis: A clinical diagnosis is often made based on symptoms and exam. Imaging (ultrasound or MRI) can help identify ovarian endometriomas, but laparoscopy is the only way to definitively diagnose and stage endometriosis (ACOG).
  • Fibroids: Usually identified with pelvic exam and confirmed by imaging, especially transvaginal ultrasound. MRI can help map fibroid number, size, and location when planning procedures (ACOG).

Treatment options

Care is personalized based on age, symptoms, fertility goals, and the size/location of lesions or fibroids.

Endometriosis

  • Pain control: NSAIDs may reduce cramps and pelvic pain.
  • Hormonal therapies: Combined hormonal contraceptives (pill/patch/ring), progestins (including the levonorgestrel IUD), and gonadotropin-releasing hormone (GnRH) medicines can suppress lesions and pain.
  • FDA-approved options: Oral GnRH antagonist elagolix for moderate-to-severe pain (FDA); a once-daily relugolix combination (estradiol/norethindrone acetate) is also approved for endometriosis-associated pain (FDA).
  • Surgery: Laparoscopic excision or ablation of lesions can relieve pain and may improve fertility for some. Recurrence is possible; medical therapy is often used after surgery.
  • Fertility care: Options range from timed intercourse/ovulation induction to in vitro fertilization (IVF), depending on age, ovarian reserve, and extent of disease.

Fibroids

  • Watchful waiting: Appropriate if symptoms are mild and anemia is absent.
  • Medical therapy: NSAIDs for cramps; tranexamic acid during menses to reduce bleeding; hormonal contraception or levonorgestrel IUD to lessen bleeding; GnRH agonists/antagonists to shrink fibroids and control bleeding.
  • FDA-approved options for heavy bleeding due to fibroids: Oral elagolix with add-back therapy (Oriahnn) (FDA) and once-daily relugolix combination therapy (Myfembree) (FDA).
  • Procedures and surgery:
    • Myomectomy to remove fibroids while preserving the uterus (hysteroscopic, laparoscopic, or open).
    • Uterine artery embolization to shrink fibroids by blocking blood supply.
    • MRI-guided focused ultrasound in select cases.
    • Hysterectomy for definitive treatment when childbearing is complete or symptoms are severe.

Note: Decisions about surgical approach consider age, fertility goals, size and number of fibroids, and the rare possibility of an unsuspected sarcoma. Discuss risks and benefits with your surgeon (see ACOG).

Fertility considerations

  • Endometriosis: Can affect fertility through inflammation, adhesions, and ovarian involvement. Many people conceive with medical or surgical management; some require IVF.
  • Fibroids: Submucosal and certain intramural fibroids may impair fertility or increase miscarriage risk; removing cavity-distorting fibroids can improve outcomes in some cases.

When to see a clinician

  • Severe period pain that disrupts daily life.
  • Heavy bleeding (e.g., soaking through a pad or tampon every hour for several hours) or symptoms of anemia (fatigue, lightheadedness).
  • Pelvic pain, persistent pressure, or bloating.
  • Difficulty getting pregnant after 6–12 months of trying (depending on age).

Key takeaways

  • Neither endometriosis nor fibroids are cancers.
  • Endometriosis slightly raises the risk of certain ovarian cancers, but the absolute risk is low.
  • Fibroids are benign and do not turn into cancer; uterine sarcoma is a separate, rare disease.
  • Both conditions are treatable with a range of medical and surgical options tailored to your goals.

Trusted sources and further reading

This article is for general education and is not a substitute for personal medical advice. If you have symptoms or concerns, speak with a qualified clinician.

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