Are too many imaging tests being performed in women with an adnexal mass?

Objective — To evaluate the patterns of radiologic imaging requested by family physicians and gynaecologists in the work-up of women found to have an adnexal mass on pelvic ultrasound, and to evaluate whether advanced imaging tests are associated with more appropriate referral of women with a high-risk adnexal mass to gynaecologic oncologists.

Methods — Centralized provincial databases of healthcare usage were used to identify women aged 45 and older who had a pelvic ultrasound examination between 2006 and 2008. Subsequent imaging tests ordered were identified according to physician specialty. For women who proceeded to laparotomy, logistic regression was performed to determine which imaging tests enabled primary physicians to make appropriate referrals of women with high risk adnexal tumours to a gynaecologic oncologist.

Results — The researchers identified 193 261 women aged 45 and older who had a pelvic ultrasound. Of these, 19 949 (10.3%) had a subsequent laparotomy; 2223 women were categorized as having a benign adnexal mass, 627 were categorized as having a malignant adnexal mass, and the remainder had another diagnosis such as uterine fibroid. Up to 12% of women had a pelvic MRI, and 58% of women had a CT scan after a pelvic ultrasound. Family physicians referred 95% of women with a high-risk ovarian mass to a gynaecologic surgeon rather than to a gynaecologic oncologist, and gynaecologists referred 47% of such women to a gynaecologic oncologist after imaging. Gynaecologic oncologists operated on 55% of women with a malignant adnexal mass. On multivariate analysis, a preoperative CT scan (OR 3.58; P < 0.001) and a CT scan and MRI (OR 7.78; P < 0.001) were associated with surgery performed by a gynaecologic oncologist, but a preoperative MRI alone was not significantly associated (OR 1.86; P = 0.09). After ultrasound alone the mean time to surgery was 100 days; this increased significantly when further imaging tests were performed (with additional CT to 131 days, with MRI to 170 days, and with CT and MRI to 179 days; P = 0.002).

Conclusion — Performing a pelvic MRI after a pelvic ultrasound does not increase the rate of referral of women with a high-risk adnexal mass to a gynaecologic oncologist. A consensus on appropriate imaging and triage is needed when an adnexal mass is identified on ultrasound.