Uterine fibroids are common, non-cancerous growths that develop within the uterus. They affect a significant number of women, with estimates suggesting that between 40% and 80% of women may develop them by age 50. These growths, also known as leiomyomas, are benign and do not increase the risk of uterine cancer. Many women with fibroids experience no symptoms and may not even be aware of their presence.
Understanding Uterine Fibroids
Uterine fibroids are composed of muscle and fibrous tissue and can vary considerably in size, from as small as a seed to larger than a grapefruit. They can grow in different locations within the uterus, influencing the type of symptoms experienced. Intramural fibroids grow within the muscular wall of the uterus and are the most common type. Submucosal fibroids develop just beneath the inner lining of the uterus and can bulge into the uterine cavity, while subserosal fibroids form on the outer surface of the uterus.
Fibroids can cause a range of symptoms depending on their size, number, and location. Common symptoms include heavy or prolonged menstrual bleeding, which can sometimes lead to anemia, and pelvic pain or pressure. Some women also experience frequent urination due to fibroids pressing on the bladder, constipation, or discomfort during sexual activity.
The Relationship Between Fibroids and Cancer
Uterine fibroids are benign and do not turn into cancer. Having fibroids does not increase a woman’s risk of developing uterine cancer. The rare concern arises from a distinct and aggressive type of uterine cancer called uterine leiomyosarcoma (LMS).
Uterine leiomyosarcoma is a rare malignancy that arises from the smooth muscle of the uterus, similar to where fibroids originate. However, LMS is a separate condition and is not believed to develop from pre-existing benign fibroids. This cancer is rare, affecting approximately 6 in every 1 million women in the United States each year, and accounts for a very small percentage of all uterine malignancies, around 1-2%.
Identifying Malignant Uterine Growths
Differentiating uterine leiomyosarcoma (LMS) from benign fibroids before surgery can be challenging because their symptoms can be similar. Imaging techniques like ultrasound or MRI often cannot definitively distinguish between the two. While MRI is considered the best imaging modality for assessing uterine masses, some features that might suggest LMS, such as rapid growth, irregular outlines, or certain signal intensities, can also be present in atypical benign fibroids.
Rapid growth of a presumed fibroid, particularly after menopause, can be a potential red flag for LMS, though it is not a definitive indicator. In postmenopausal women, any new or growing uterine mass warrants evaluation. Ultimately, a definitive diagnosis of LMS requires pathological examination of the tissue after surgical removal.
When to Consult a Doctor
It is advisable to consult a healthcare professional if you experience new or worsening pelvic symptoms. These symptoms might include unusually heavy or prolonged bleeding, bleeding between periods, severe pelvic pain or pressure, or changes in bladder or bowel habits. While such symptoms are frequently caused by benign conditions like fibroids, medical evaluation is important for proper diagnosis and management.
Regular gynecological check-ups are also important for maintaining overall reproductive health and for the early detection of potential health issues. These routine visits allow for discussions about any concerns, and enable healthcare providers to identify and address conditions early, even if they are not causing severe symptoms.