Letrozole add-on in the Treatment of Cesarean Scar Pregnancy

Evaluation of the Therapeutic Effect of Adding Letrozole to the Protocol of Combined Treatment of Cesarean Scar Pregnancy

It is hypothesized that the inhibition of estradiol production by letrozole may interfere with physiological effects of progesterone necessary to maintain the pregnancy. There is no reference treatment of cesarean scar pregnancy (CSP) as the limited number of cases precludes the extrapolation of results. In our center we successfully use two-step treatment with methotrexate (MTX) followed by hysteroscopic removal of products of conception (POC). The time in between is needed to achieve a decrease in the trophoblast's vital potential (B-hCG fall) and its vascularization. Additional administration of letrozole could further reduce the vital potential of the pregnancy, eliminating the need for another dose of MTX, resulting in faster healing and lower rate of complications.

A prospective cohort study is conducted among women with cesarean scar pregnancy (CSP). Women with increasing B-human chorionic gonadotropin (B-hCG) concentrations are included. Two study arms were planned: women treated with a single dose of 100 mg MTX intravenously and 50 mg MTX in intra-amniotic injection (day 0), along with 30 mg potassium chloride in case of positive fetal heartbeat (FH) women treated with a single dose of 100 mg MTX intravenously and 50 mg MTX in intra-amniotic injection (day 0), along with 30 mg potassium chloride in case of positive fetal heartbeat (FH) with additional use of letrozole 5 mg orally (from day 0) for 10 days. Blood parameters (B-hCG, hemoglobin, total blood count, creatinine, urea, alanine/aspartate transaminase, gamma-glutamyltransferase, bilirubin) were tested on days 0,4,7, followed by B-hCG concentration measurement every 7 days until surgery. After obtaining satisfactory decrease in B-hCG and POC vascularization, women underwent hysteroscopic evacuation of POC. Blood loss parameters, frequency of conversion from hysteroscopy to laparoscopy and laparotomy were measured. The women were given the option to choose the treatment used in the study. All enrolled women gave informed written consent to participate in the study.

MTX in a single dose of 100 mg intravenously and 50 mg in intra-amniotic injection (day 0), along with 30 mg potassium chloride in case of positive fetal heartbeat (FH), and subsequent hysteroscopic evacuation of products of conception (POC)

MTX in a single dose of 100 mg intravenously and 50 mg in intra-amniotic injection (day 0), along with 30 mg potassium chloride in case of positive fetal heartbeat (FH) + Letrozole in a daily dose of 5 mg (2 x 2.5 mg) orally for 10 days from day 0, and subsequent hysteroscopic evacuation of products of conception (POC)

Decrease in hemoglobin concentration in g/dl on day 1 after the procedure compared to the pre-procedure concentration

Changes in the concentrations of serum total bilirubin (mg/dl) in the course of treatment (day 0,4,7)

Changes in the concentrations of aspartate transaminase (IU/l) in the course of treatment (day 0,4,7)

Changes in the concentrations of gamma-glutamyltransferase (IU/l) in the course of treatment (day 0,4,7)

Inclusion Criteria: CSP confirmed on pelvic ultrasound consent of the Bioethics Committee for termination of CSP increasing B-hCG concentrations Exclusion Criteria: heterotopic pregnancy decreasing B-hCG concentrations

Jagiellonian University Medical College, Department of Gynecology and Obstetrics, Clinic of Gynecological Endocrinology