Sonographic characteristics of post-molar gestational trophoblastic neoplasia at diagnosis and during follow-up, and relationship with methotrexate resistance.

OBJECTIVES

To describe the sonographic characteristics of post-molar gestational trophoblastic neoplasia (GTN) at diagnosis and during follow-up, and to assess their association with methotrexate (MTX) resistance (R) as first-line chemotherapy.

METHODS

This was a retrospective study of all women treated for post-molar GTN at Karolinska University Hospital, Stockholm, Sweden, between October 2010 and December 2017, who had undergone expert transvaginal ultrasound assessment ≤ 2 weeks prior to, or ≤ 1 week after, the start of first-line MTX treatment. Women with a detectable uterine lesion were followed up with repeat scans during treatment, as well as after treatment in cases of persistent lesions. The association between MTX-R and sonographic findings at inclusion was assessed.

RESULTS

Of 47 eligible women, 36 were included in the analysis after excluding those who had not undergone structured transvaginal ultrasound assessment and those who started treatment at another center. The median age at diagnosis was 33 (interquartile range (IQR), 27-43) years and 35/36 (97%) women were in the FIGO low-risk group (risk score, 0-6). At inclusion, no uterine lesions were found in eight (22%) women, focal lesions in 24 (67%) women and global lesions in four (11%) women. Median maximum lesion diameter was 40.4 (IQR, 31.3-49.4) mm and 26/28 (93%) lesions had a color score of 3 or 4. Arteriovenous fistulas were found in 9/28 (32%) women and theca lutein cysts in 4/36 (11%) women. Four women with GTN lesion at inclusion underwent hysterectomy prior to the first follow-up ultrasound scan and a fifth woman with a growing lesion underwent hysterectomy, which revealed persistent viable trophoblastic tissue. All remaining women reached complete remission and median time to human chorionic gonadotropin normalization was 2.7 (IQR, 1.4-3.7) months. During ultrasound follow-up, 88% (21/24) of lesions resolved completely. Two women with a persisting lesion remained in complete remission. Median time to disappearance of vascularity was 5.8 (IQR, 3.7-9.3) months and median time to resolution of the lesion was 6.8 (IQR, 3.7-9.3) months. MTX-R developed in 12/31 (39%) women. Uterine tumors ≥ 4 cm (73% vs 17%; P = 0.008) and global lesions (25% vs 0%; P = 0.03) were significantly more common in women with compared to those without MTX-R.

CONCLUSION

Uterine lesions were detected at the time of diagnosis in 78% of women with post-molar GTN. The vast majority of the lesions resolved completely during follow-up, after a median of 7 months. MTX-R was more common in uterine tumors of 4 cm, or larger, and in global lesions. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.