Do fibroids become cancerous?

 

Two types of cancer may occur in the uterus. Classic uterine cancer (endometrial cancer) originates from the inner surface of the uterus called endometrium, which causes menstrual bleeding. Endometrial cancer is the most common type of cancer in the uterus (constitutes approximately 95% of all uterine cancers) and is usually found in women close to or in menopause. The classic symptom is bleeding between periods or bleeding again after menopause. Since these symptoms are remarkable for the patient, an early visit to the doctor is made and the diagnosis is made early and easily with a kind of curettage called endometrial biopsy. Most of the patients can regain their health with hysterectomy. ​ ​

 

The second type of cancer seen in the uterus is sarcoma. Sarcomas arise from muscle tissue and connective tissue cells in the uterus. They constitute only 5% of uterine cancers. Unlike endometrial cancer, they can also occur in young women and do not cause typical symptoms. The most useful imaging method in diagnosis is MRI, but biopsy is absolutely necessary for definitive diagnosis. Since sarcomas are located in the muscle layer of the uterus, endometrial biopsy is insufficient for diagnosis, the ideal method is trucut (core) needle biopsy under ultrasound guidance.

 

Fibroids are not directly related to either type of cancer. Endometrial cancer already originates from the endometrium independently of fibroids. Sarcomas originating from the uterine muscle tissue are also thought to originate from normal muscle cells in the uterine tissue, not from existing fibroids. Therefore, a patient with fibroids has the same risk of developing sarcoma or other types of cancer in the uterus as those without fibroids.