Carboprost Tromethamine (Hemabate) for Resection of Fibroids-a Pilot Study

Uterine fibroids, also known as leiomyomas, are estimated to affect over 80% of women by the time menopause begins. Many women are asymptomatic and remain undiagnosed, therefore the prevalence of the disease is likely underestimated. Leiomyomas are the most common neoplasms to affect women and can cause morbidities such as heavy menstrual bleeding (HMB) and infertility. According to the American College of Obstetricians and Gynecologists, one-fourth of the women with leiomyomas befit treatment, presenting with heavy or prolonged menstrual bleeding, abdominal protrusion, bowel or bladder dysfunction, infertility, recurrent pregnancy loss, painful menses, or pelvic pain. Risk factors associated with developing leiomyomas include: early menarche, use of oral hormonal contraceptives before the age of 16 years, African descent, and an increased body mass index (BMI) (StatPearls Leiomyoma). Factors that may lower the incidence of leiomyomas include: increased parity, use of depot medroxyprogesterone acetate (DMPA) or oral hormonal contraceptives for any duration.

Leiomyomas are benign tumors which arise from monoclonal smooth muscle cells of the uterus (StatPearls Leiomyoma); cells mostly composed of extracellular matrix and encapsulated in a pseudocapsule of areolar tissue. These tumor cells characteristically express higher levels of estrogen and progesterone receptors than normal myometrial cells, and ovarian steroids such as estradiol and progesterone enhance leiomyoma growth. Studies have shown that the size of leiomyomas decrease after menopause when ovarian steroid hormones decline. Leiomyoma cells typically exhibit a low mitotic index. Uterine leiomyomas can impact fertility in multiple ways, for instance, leiomyomas can impede sperm migration, interrupt ovum transport or embryo implantation, and can cause early pregnancy loss. Current treatment options for management of leiomyomas including medical therapies and surgical intervention.

Surgically resecting fibroids is one of the most common procedures performed for women of reproductive age. The goal of surgery is to mitigate symptoms and lower the risk of recurrence. Fibroids identified as FIGO 0 or 1 are typically resected completely at hysteroscopy. Unfortunately, fibroids categorized as FIGO 2 when approached hysteroscopically are almost never completely removed given that there can remain residual leiomyoma within the myometrium that is inaccessible. This commonly requires follow up procedures in the coming 6 months as the myometrial portion migrates into the cavity allowing it to be accessible hysteroscopically. Similarly at laparoscopy/laparotomy, FIGO 6 or 7 fibroids are easily resected completely without significant myometrial disruption. In contrast, FIGO 3-5 fibroids require a much more invasive approach into the myometrium, potentially increasing the risk of uterine rupture during pregnancy, a potentially life-threatening event. Techniques have been developed to promote intraoperative fibroid migration towards the access point (laparoscopy/laparotomy/hysteroscopy) with some success. This is a pilot study to determine whether intramural carboprost at low concentrations can facilitate fibroid migration and minimize the risk of carboprost-related side effects. Using carboprost intraoperatively is relatively simple, does not require additional instrumentation, and potentially results in a more complete resection, reducing operative times and re-operation. With the use of carboprost, the myoma is expelled due to the myometrial contraction, and the leiomyoma is shaved down to the myometrium surface, nullifying the need to deeply invade the myometrium.