FIBROID & CANCER

A fibroid cannot become a cancer. However a fibroid-like cancer called leiomyosarcoma, can look and behave like a fibroid. The two conditions are totally different but because they appear almost identical on ultrasound, confusion arises.

The chance is very very low. Studies of large patient populations around the world report the risk of leiomyosarcoma as 1:2000-8300. ( Pritts 2015 )

In Singapore, data from the largest Women’s Hospital reports 4 cases of leiomyosarcoma in 4000 surgeries of Laparoscopic Myomectomy, giving a cancer risk of 1:1000.

The 1:498 chance of cancer quoted by FDA USA is widely regarded as a gross over-estimate. This figure came from only a few small studies, including other cancers besides leiomyosarcoma and selecting a large proportion of elderly women. These factors elevated the risk of cancer. As a comparison, when the COVID death toll reached 500,000 Americans, it was equivalent to 1:670 Americans dying from COVID in a Pandemic.

No. Fibroids can grow normally at about 9% every 6 months with growth being faster in certain races. (Peddada 2008)

A small study looking at the risk of cancer in rapidly growing fibroids found 0.27% of growing fibroids as cancer, compared to 0.23% of non-growing fibroids as cancer. (Parker 1994)

A definite diagnosis of leiomyosarcoma is obtained only after surgery. There is no test to confirm leiomyosarcoma before surgery. Cancer marker like LDH Isoenzyme III together with MRI have been used to identify leiomyosarcoma before surgery. However the tests are not 100% accurate. (Goto 2002)

Myomectomy itself can spread leiomyosarcoma regardless of laparoscopy or open surgery. Only a total womb removal (hysterectomy) without cutting the fibroid can prevent some cancer spread. In laparoscopy, fibroids need to be cut into strips for removal. Cutting the fibroid into strips is called morcellation. Morcellation done with a power morcellator can spread the cancer much more than morcellation done with a normal knife. Morcellation within a containment bag is thought to reduce the cancer spread.

When leiomyosarcoma is diagnosed after surgery, the whole womb, ovaries and other areas of possible cancer involvement need to be removed. The outcome for leiomyosarcoma is generally poor, even in the early stage. There is 50-70% chance of the cancer returning within 3 years. If the leiomyosarcoma was morcellated, there is a 3-4 times increased risk of cancer spread and recurrence. (Bogani 2015)