Prospective external validation of IOTA three-step strategy for characterizing and classifying adnexal masses and retrospective assessment of alternative two-step strategy using simple-rules risk

OBJECTIVES

To perform an external validation of the diagnostic performance of the three-step strategy proposed by the International Ovarian Tumor Analysis (IOTA) group for classifying adnexal masses as benign or malignant, when ultrasound is performed by non-expert sonographers in the first two steps. The second objective was to assess the diagnostic performance of an alternative strategy using simple-rules risk (SRR), instead of simple rules (SR), in the second step.

METHODS

This was a prospective observational study conducted at two university hospitals, from September 2015 to August 2017, of consecutive patients diagnosed with an adnexal mass. All women were evaluated by ultrasound using the IOTA three-step strategy. Non-expert sonographers performed the first step (use of simple descriptors to classify the masses) and the second step (use of SR if the mass could not be classified in the first step); masses that could not be classified in the first two steps were categorized by an expert sonographer based on their subjective assessment (third step). The reference standard was histological diagnosis in patients who underwent surgery or at least 12 months of follow-up in cases managed expectantly. The sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratios and overall accuracy of the IOTA three-step strategy were estimated. Furthermore, we evaluated retrospectively an alternative two-step strategy using SRR in the second step to categorize the masses not classifiable with simple descriptors, classifying the lesions as being of low, intermediate or high risk for malignancy. The diagnostic performance of this strategy was estimated by calculating its sensitivity and specificity, assuming surgical intervention for intermediate- or high-risk lesions.

RESULTS

The study included 283 patients (median age, 48 (range, 18-90) years), of whom 165 (58.3%) were premenopausal and 118 (41.7%) postmenopausal. Two hundred and sixteen (76.3%) women underwent surgery (154 benign and 62 malignant masses) and 67 (23.7%) were managed expectantly with serial ultrasound follow-up for at least 12 months. All expectantly managed masses were considered benign because no sonographic changes suggestive of malignancy were observed during follow-up. Simple descriptors could be applied in 126 (44.5%) masses. Of the remaining 157 lesions, 112 (39.6%) could be characterized using SR. Therefore, 238 (84.1%) masses could be classified by non-expert sonographers in the first two steps. Of the remaining 45 (15.9%) masses, all could be classified by an expert sonographer. Overall sensitivity, specificity, LR+ and LR- of the IOTA three-step strategy were 95.2%, 97.7%, 42.1 and 0.05, respectively. The diagnostic accuracy was 97.2%. Following the two-step strategy using SRR in the second step, of the 157 lesions not classified with simple descriptors, 42, 38 and 77 presented low, intermediate or high risk for malignancy, respectively. Based on this method, 210 women would have undergone surgical treatment. The sensitivity and specificity of this two-step strategy were 98.4% and 63.8%, respectively.

CONCLUSIONS

The IOTA three-step strategy shows high accuracy for discriminating between benign and malignant adnexal lesions when used by non-expert sonographers. An alternative strategy using the SRR calculator in the second step might improve on this diagnostic performance by decreasing the number of surgical interventions and increasing sensitivity. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

External validation of IOTA simple descriptors and simple rules for classifying adnexal masses

OBJECTIVE

To assess the diagnostic performance of a three-step strategy proposed by the International Ovarian Tumor Analysis (IOTA) Group for discriminating between benign and malignant adnexal masses.

METHODS

This was a prospective observational study, performed at two tertiary-care university hospitals, of women diagnosed with an adnexal mass on transvaginal or transabdominal ultrasound between December 2012 and December 2014. Women were scheduled for an ultrasound evaluation, which was initially performed by non-expert examiners. The examiner had to classify the mass using 'simple descriptors' (first step) and, if not possible, using 'simple rules' (second step). For inconclusive masses, an expert examiner classified the mass according to their subjective impression (third step). Masses were managed expectantly, with serial follow-up examinations, or surgically, according to ultrasound findings and clinical symptoms. Histology was used as the reference standard. Masses that were managed expectantly with at least 1 year of follow-up were considered as benign for analytical purposes. Women with less than 1 year of follow-up were not included in the study.

RESULTS

Six hundred and sixty-six women were included (median age, 41 (range, 18-81) years) of whom 514 were premenopausal and 152 were postmenopausal. Based on the three-step strategy, 362 women had surgical removal of the mass (53 malignant and 309 benign), 71 masses resolved spontaneously and 233 persisted. Four hundred and forty-eight (67.3%) of 666 masses could be classified using simple descriptors and, of the 218 that could not, 147 (67.4%) were classified using simple rules. Of the remaining 71 masses, the expert examiner classified 45 as benign, 12 as malignant and 14 as uncertain. Overall sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of the three-step strategy were 94.3%, 94.9%, 18.6 and 0.06, respectively.

CONCLUSION

The IOTA three-step strategy, based on the sequential use of simple descriptors, simple rules and expert evaluation, performs well for classifying adnexal masses as benign or malignant. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Performance of three-dimensional power Doppler angiography as third-step assessment in differential diagnosis of adnexal masses

OBJECTIVE

To evaluate the contribution of three-dimensional (3D) power Doppler angiography (3D-PDA) to the differential diagnosis of adnexal masses.

METHODS

This was a prospective study in women diagnosed with a persistent adnexal mass and subsequently scheduled for surgery in a tertiary university hospital. All women were evaluated by transvaginal/transrectal ultrasound according to a predetermined three-step protocol, with transabdominal ultrasound being performed in some cases. First, morphological evaluation of the mass was performed using gray-scale 'pattern recognition' (first step). Lesions diagnosed as having a benign pattern were considered as being at low risk of malignancy whereas tumors with solid components, ascites and/or signs of carcinomatosis were considered as being at high risk of malignancy. In both cases no further test was performed and a decision regarding clinical management, either for follow-up or surgery, was taken. Tumors with solid components but without signs of ascites or carcinomatosis were considered as being at intermediate risk of malignancy. These lesions were assessed by two-dimensional (2D) PDA to evaluate tumor vascularity (color score) (second step). Solid tumors with a color score of 1 or 2 were considered as benign and no further test was performed, while tumors with a color score of 2, 3 or 4 within solid components or a color score of 3 or 4 in the case of a solid tumor were considered as malignant. The latter group underwent 3D-PDA assessment (third step). Vascularization index (VI) was calculated in a 1-mL sphere of the most vascularized area of the tumor. When a VI ≥ 24.015% was found, the tumor was considered as malignant. All masses were removed surgically and definitive histological diagnosis was used as the gold standard. Sensitivity and specificity for each strategy were calculated and compared. In the case of bilateral tumors, only the more suspicious one was used for analysis.

RESULTS

A total of 367 adnexal masses diagnosed in 367 women (mean age, 46.5 (range, 18-80) years) were evaluated during the study period. Of these, 86 masses were malignant and 281 were benign. The sensitivity and specificity for each assessment strategy were as follows: one-step, 97.7% and 78.6%; two-step, 94.2% and 97.9% (P < 0.001 for specificity when compared with that of one-step); three-step, 90.7% and 98.9% (not statistically significant when compared with that of two-step).

CONCLUSIONS

The addition of 2D-PDA in the differential diagnosis of an adnexal mass significantly increases specificity while sensitivity remains high; however performing subsequent 3D-PDA does not provide additional information or further improve diagnostic performance subsequent to 2D-PDA.

IOTA simple rules for discriminating between benign and malignant adnexal masses: prospective external validation

OBJECTIVE

To determine the diagnostic performance of International Ovarian Tumor Analysis (IOTA) 'simple' rules for discriminating between benign and malignant adnexal masses.

METHODS

A prospective study was performed between January 2011 and June 2012. Eligible patients were women diagnosed with a persistent adnexal mass who presented to the participating centers. Four trainees evaluated the adnexal mass by transvaginal ultrasound under the supervision of an expert examiner. The trainee analyzed the mass according to IOTA simple rules and provided a diagnosis of benign, malignant or inconclusive. All women included in the study underwent surgery and tumor removal in the center of recruitment. Diagnostic performance was assessed by calculating sensitivity, specificity and positive (LR+) and negative (LR-) likelihood ratios.

RESULTS

A total of 340 women were included (mean patient age, 42.1 (range, 13-79) years). Of the tumors, 55 (16.2%) were malignant and 285 (83.8%) were benign. The IOTA simple rules could be applied in 270 (79.4%) cases. In these cases, sensitivity was 87.9% (95% CI, 72.4-95.2), specificity 97.5% (95% CI, 94.6-98.8), LR+ 34.7 (95% CI, 15.6-77.3) and LR- 0.12 (95% CI, 0.05-0.31).

CONCLUSIONS

Application of the IOTA simple rules yielded acceptable results in terms of specificity in the hands of non-expert examiners. However, with non-expert examiners there was a 12% false-negative rate, which is relatively high.

[Diagnosis of endometriosis]

There are no sufficiently sensitive and specific signs and symptoms or diagnostic tests for the clinical diagnosis of endometriosis, and no diagnostic strategy is supported by evidence of effectiveness. Pelvic and rectal examinations should be performed, although the yield of the physical examination is low. Laboratory tests and radiological examinations are usually not warranted. Measurement of CA 125 levels may be useful for monitoring disease progress, and MRI has a high sensitivity in detecting endometrial cysts but poor diagnostic accuracy for endometriosis in general. Patients with persistent symptoms after empirical treatment should be referred for laparoscopy, the preferred method for diagnosis of endometriosis.

[Angiogenesis and endometriosis]

Endometriosis is a common gynaecological disease of unknown aetiology. Angiogenesis appears to be one of the processes involved in its pathogenesis. Angiogenic factors are increased in the peritoneal fluid of patients with endometriosis (McLaren 1996 et al; Taylor et al, 2002), in peritoneal implants (Ferriani et al, 1993) and in ovarian endometriomas. On the other hand, some researchers have found that angiogenesis is related to pelvic pain. We speculated that ovarian endometriomas in patients presenting with pelvic pain would be more angiogenic than those in asymptomatic women and that their vascular features would therefore be different.

[Endometriosis]

Endometriosis is a common gynaecological disease of unknown aetiology which affects an estimated 10% to 15% of all premenopausal women. It is defined as the presence of endometrial tissue, consisting of both glandular epithelium and stroma, outside the uterine cavity. Three different clinical entities of endometriosis can be distinguished: peritoneal endometriosis, ovarian endometriosis and deep invasive endometriosis. There are several theories to explain their pathogenesis: metaplasia of the mesothelium, in situ development of Müllerian remnants in the rectovaginal area (deep-invasive lesions) or retrograde transplantation of shed menstrual effluent (peritoneal implants). The most widely accepted hypothesis for the development of endometriosis is retrograde menstruation. However, some other factor renders certain women susceptible to the implantation and growth of this ectopic endometrium.