Types of Cancer

Fibroids and Cancer

Do Growing Fibroids Mean Cancer?

Fibroids are benign uterine growths. Furthermore, fibroids do not turn into cancer. Genetic studies of fibroids and uterine muscle cancer (sarcoma) show that they have very different genetic mutations and that sarcomas do not develop from fibroids. However, a leiomyosarcoma, an extremely rare malignant tumor of the uterine muscle, also causes enlargement of the uterus. But only 1 out of every 1,000 women admitted to the hospital for surgery because of problems thought to be from fibroids will be found to have a sarcoma. And since 80 percent of women with fibroids are never admitted to a hospital for surgery, the incidence of sarcoma in all women with fibroids is extraordinarily low. The average age of women who develop fibroids is 38. Although sarcoma can rarely occur in young women, the average age of a woman who develops a sarcoma is 63. So, if you have fibroids, there is not much reason to worry about sarcoma.

Most gynecologic textbooks teach physicians that if a woman has a rapidly growing uterus, she should have surgery to see if she has a uterine sarcoma. Surgery would be needed to remove tissue for microscopic analysis. However, during the course of my training and years in practice, I have never seen a "rapidly growing fibroid" actually turn out to be a sarcoma.

To study this issue, I did a clinical study at the hospitals where I practice and reviewed the charts of 1,332 women admitted for surgery because of fibroids. Only three women (two tenths of 1%) were found to have a sarcoma. Of the 371 patients admitted because of rapidly growing fibroids, only one (three tenths of 1%) had a sarcoma. This study showed that the risk of developing a sarcoma is extremely low, even if your fibroids are rapidly growing.

I am including the abstract from our article:

Uterine sarcoma in patients operated on for presumed leiomyomas and rapidly growing leiomyomas. Authors: Parker W, Berek J, Fu YS. Obstetrics and Gynecology 1994 83:414-8

Fibroids-especially those located in the cavity of the uterus-may increase the chance of a miscarriage or may cause a woman to go into labor before her due date (premature labor). Fibroids may also increase the chance that the baby is not positioned to come out headfirst. This can increase the need for cesarean section. Rarely, fibroids can cause complications of pregnancy called placental abruption and postpartum hemorrhage

Objective: To determine the incidence of uterine sarcoma in patients operated on for symptomatic uterine leiomyomas or "rapidly growing" leiomyomas. Methods: Medical records of 1332 women admitted to either of two community hospitals between 1988-1992 for hysterectomy or myomectomy for uterine leiomyomas were reviewed. The incidence of leiomyosarcoma, endometrial stromal sarcoma and mixed mesodermal tumor was calculated. Patient ages, admitting symptoms, operative and pathologic findings were analyzed. Included in the study were 371 women (28%) operated on for "rapidly growing" leiomyomas. All patients operated on during the same interval and found to have a uterine sarcoma were reviewed.

Results: One of 1332 patients (.07%) operated on for presumed leiomyoma was found to have a leiomyosarcoma This woman was the only patient found to have a sarcoma among 371 (0.27%) women operated on for "rapid growth" of the uterus. None of 198 patients who met a published definition of rapid growth had a uterine sarcoma. Two women (0.15%) were found to have endometrial stromal sarcoma and none was found to have a mixed mesodermal tumor. During the same interval, nine additional patients were found to have uterine sarcomas, and for these the preoperative diagnosis was sarcoma in four, endometrial cancer in three, ovarian cancer in one, and prolapsed uterus in one. Conclusions: The total incidence of uterine sarcoma (leiomyosarcoma, endometrial stromal sarcoma, and mixed mesodermal tumor) among patients operated on for uterine leiomyoma is extremely low (0.23%). The incidence of sarcoma among patients operated on for "rapidly growing" leiomyoma (0.27%), or those who met published criteria for rapid growth (0%) does not substantiate the concept of increased risk of sarcoma in these women.

Can the Diagnosis of Sarcoma be Made Without Surgery?

A recent study found that by using a combination of an MRI (with a dye given intravenously) and a blood test called LDH the diagnosis of uterine sarcoma could be reliably made without any surgery. (see webpage "Do I Need Surgery for Fibroids?", question - What If There Is Concern That the Fibroids Might Be Cancer?)

What Should You Do if You have a Growing Fibroid?

If you have a growing fibroid, it is perfectly reasonable to be followed by having a pelvic examination every one to three months. If the fibroid begins to cause bothersome symptoms, then surgery may be considered. If the fibroid continues to grow very rapidly, doubling in size in a few weeks or months, then surgery may be indicated. However, because of the rarity of sarcomas (especially in women younger than fifty), we found no justification for assuming that growth in a fibroid means that cancer is developing. And, as stated before, there is no evidence to suggest that fibroids turn into cancer. Therefore, surgery is not usually indicated.

If you are a woman in her fifties or sixties, the issue of growth of fibroids is different. Published reports show that sarcomas may occur in women in their fifties and sixties. If you are postmenopausal and not on estrogen replacement therapy, any growth in your uterus may be cause for concern. Until there is further confirmation of the MRI/LDH tests, surgery may be needed to remove the growing fibroid. A pathologist performs an examination of the tissue under a microscope to conclusively show if cancer is present.

Do Birth Control Pills Cause Fibroids to Grow?

Birth control pills do not appear to cause the growth of fibroids. Three studies have tried to answer this question; one study found a slightly increased risk of fibroids, another study found no increased risk and the third study found a slightly decreased risk. However, these studies are retrospective and may contain selection bias.

Does Menopausal Hormone Therapy Cause Fibroids to Grow?

Postmenopausal hormone therapy does not normally cause fibroid growth. A few studies have tried to answer this question. After three years, only 8% of postmenopausal women with fibroids who were taking hormones had any increase in fibroid size. If any increase in uterine size is noted, it is likely related to the dose of progestins.

A study found that for women taking oral estrogen plus a low dose of synthetic progesterone for one year, 23% had a slight increase in size (about 1 inch in diameter) while 50% of the women taking a higher dose had an increase in size. Estrogen patches or skin creams (with synthetic progesterone) may cause slight (1/4 inch) increase in the diameter of fibroids while oral estrogen (with synthetic progesterone) caused no increase in size.

In our fibroid study, we found that in the small number of postmenopausal women (7 women) who were taking estrogen and were noted to have growing fibroids, none was found to have a sarcoma during surgery. Therefore, a reasonable option for these women might be to discontinue the estrogen and see if the uterus shrinks back to its previous size. If the fibroids do shrink (because the estrogen and progestin is no longer present), then you could stay off the hormones and avoid surgery. Or, if the hormones are necessary for bothersome menopausal symptoms, you can restart them with the knowledge that surgery will probably be necessary if the fibroids grow again. If you stop taking hormones and your uterus does not shrink, or especially if it continues to grow, then surgery should be performed because of the possibility of uterine sarcoma.

Can Fibroids turn into Cancer?

Often it is believed that all tumors some way or the other are related to cancer. Women with tumor in uterus are more pessimistic thinking the tumor as cancerous. It has been proved and well researched that Fibroids are non-cancerous and they have no associations with cancer. They are benign and any one who has been treated for fibroids hold no risk of cancer for the same.

Can Fibroids Lead To Cancer?

In most women, fibroids do not lead to cancer. Rarely, however, fibroids can turn into a cancer called a leiomyosarcoma. This happens to an estimated 1 in 1,000 women who have fibroids. Some cancerous tumors may develop directly from normal tissue in the uterus. The average age of women with leiomyosarcoma is 55.

Warning signs of cancer may include:

• rapid growth of the fibroids or the uterus
• vaginal bleeding after a woman has passed menopause.

If a woman has either of these problems, she should see a doctor right away.