Operator Expertise is Important when Performing Ultrasound Exams to Detect Ovarian Cancer

Using expert ultrasonographers over regular operators for diagnosing ovarian cancer results in significant reduction in the overall number of diagnostic procedures required as well as in the length of inpatient hospital stays, according to a recent report.

The advantage of expert operators, according to study investigator Dr. Joseph Yazbek and colleagues, from King's College, Guy's and St. Thomas' Hospitals (London, UK), is their greater skill in differentiating benign from malignant ovarian pathology. "This ability decreases the number of patients who are treated as potentially having ovarian cancer and aids the use of more conservative management options.”

The established way to distinguish benign from malignant tumors in the region of the ovary, uterus, or fallopian tubes (known as adnexal tumors) is assessment of structural features (such as wall structure, blood vessels, and presence of fluid) using ultrasound images. Ultrasonography, however, is subject to substantial interobserver variability, with experienced operators being significantly more accurate in their diagnosis than the less experienced. Failure to distinguish between benign and malignant masses has the unfortunate consequence of patients being referred for major abdominal surgery to rule out the possibility of cancer, as opposed to the possibility of minimally invasive surgery (laparoscopy) to remove the benign mass or a wait and see approach.

In the study, Dr. Yazbek and colleagues set out to assess whether the level of operator skill had a measurable impact on patient management. Overall, 150 patients with suspected ovarian cancer, referred to the regional gynecologic cancer center at Guy's and St Thomas' National Health System (NHS) Foundation between May 3, 2004 and February 15, 2007, were randomized to level III (expert) ultrasonography (n = 77) or level II (routine) ultrasonography (n = 73). Level III ultrasonography was undertaken by gynecologists with a special interest in gynecologic ultrasound who had more than 10 years' experience in the procedure; while level II ultrasonography was undertaken by ultrasonographers trained in gynecologic ultrasonography. For all patients both transvaginal and transabdominal scans were undertaken to ensure complete assessment of the entire abdominal cavity.

Results showed the number of major surgical staging procedures for presumed ovarian cancer undertaken in women screened by a level III (expert) ultrasonographer was 17 of 77 (22%); compared with 27 of 73 (37%) for those screened by level II ultrasonography (p = 0.049). There was also a reduction in follow-up procedures after expert sonography with the median number of follow up scans being two (range 0-5) in the level II group, compared with one (0-4) in the level III group (p = 0.0004).

"This finding is likely to be the consequence of the greatly increased proportion of patients in whom a conclusive diagnosis of the nature of the adnexal tumor was possible from level III ultrasonography compared with level II ultrasonography,” wrote the researchers, who published their study in the February 2008 issue of the journal Lancet Oncology.

Furthermore, the findings showed that a histologic diagnosis was provided to clinicians for 76 of 77 (99%) of patients in the level III group compared with only 38 out of 73 (52%) of patients in the level II group (p < 0.0001). The total number of surgical procedures was similar between the two groups--35 of 73 (48%) in the level II group versus 33 of 77 (43%) in the level III group (p = 0.53). However, the number of minimally invasive procedures was higher for the level III group than the level II group.

This, according to the investigators, is likely to have contributed to the significant decrease in the length of hospital stays for patients in the expert level III group. The median duration of hospital stay for level II group patients was six days (range 3-13 days), compared to five days (range 1-9 days) for the level III group (p = 0.01).

The researchers added that the effect of expert scanning might have been even greater if it had been used in the primary assessment of ovarian pathology. "Increased confidence in the diagnosis of benign ovarian lesions is likely to decrease the need for additional diagnostic tests, such as magnetic resonance imaging [MRI] or serum CA- [cancer antigen]-125 concentration, and also decreases the number of referrals to regional cancer centers,” they wrote in their article.

In an accompanying commentary, Dr. Usha Menon, from University College (London, UK), reported, "In the current climate, where there is an increasing effort to rationalize procedures done by medical staff, this study is extremely important.” There is urgent need, she added, for detailed cost-benefit and quality of life analyses to be undertaken for the widespread introduction of expert sonography.


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