Comparison of 'pattern recognition' and logistic regression models for discrimination between benign and malignant pelvic masses: a prospective cross validation

A nomogram for estimating the probability of ovarian cancer

OBJECTIVE

Accurate preoperative estimates of the probability of malignancy in women with adnexal masses are essential for ensuring optimal care. This study presents a new statistical model for combining predictive information and a graphic decision support tool for calculating risk of malignancy.

METHODS

The study included 153 women treated with definitive surgery for adnexal mass between 2001 and 2007 with preoperative ultrasound testing and a serum CA125. Multivariable logistic regression was used to develop a statistical model for estimating the probability of ovarian cancer as a function of age, ultrasound score, and CA125 value, with adjustments for nonlinear and interactive relationships.

RESULTS

A total of 20 cases of pathologically confirmed cancer (13 invasive malignancies, and 7 tumors of low malignant potential) were identified (20/153=13%). The model obtained excellent discrimination (ROC area=0.87), explained nearly half of the observed variation in the risk of malignancy (R²=0.43), and was well calibrated across the full range of malignancy probabilities. The model equation is represented in the form of a nomogram, which can be used to calculate preoperative probability of malignancy. At a 5% risk of malignancy threshold, the model has a sensitivity of 90% and a specificity of 73%.

CONCLUSIONS

Statistical models for estimating the probability of adnexal mass malignancy are substantially improved by including adjustments for non-linear relationships among key variables. A clinically relevant nomogram provides an objective tool to further aid clinicians in counseling patients and ensuring proper referral to surgical sub-specialists when indicated.

Improving the preoperative classification of adnexal masses as benign or malignant by second-stage tests

OBJECTIVE

The aim of this study was to establish when a second-stage diagnostic test may be of value in cases where a primary diagnostic test has given an uncertain diagnosis of the benign or malignant nature of an adnexal mass.

METHODS

The diagnostic performance with regard to discrimination between benign and malignant adnexal masses for mathematical models including ultrasound variables and for subjective evaluation of ultrasound findings by an experienced ultrasound examiner was expressed as area under the receiver-operating characteristics curve (AUC), sensitivity and specificity. These were calculated for the total study population of 1938 patients with an adnexal mass as well as for subpopulations defined by the certainty with which the diagnosis of benignity or malignancy was made. The effect of applying a second-stage test to the tumors where risk estimation was uncertain was determined.

RESULTS

The best mathematical model (LR1) had an AUC of 0.95, sensitivity of 92% and specificity of 84% when applied to all tumors. When model LR1 was applied to the 10% of tumors in which the calculated risk fell closest to the risk cut-off of the model, the AUC was 0.59, sensitivity 90% and specificity 21%. A strategy where subjective evaluation was used to classify these 10% of tumors for which LR1 performed poorly and where LR1 was used in the other 90% of tumors resulted in a sensitivity of 91% and specificity of 90%. Applying subjective evaluation to all tumors yielded an AUC of 0.95, sensitivity of 90% and specificity of 93%. Sensitivity was 81% and specificity 47% for those patients where the ultrasound examiner was uncertain about the diagnosis (n = 115; 5.9%). No mathematical model performed better than did subjective evaluation among the 115 tumors where the ultrasound examiner was uncertain.

CONCLUSION

When model LR1 is used as a primary test for discriminating between benign and malignant adnexal masses, the use of subjective evaluation of ultrasound findings by an experienced examiner as a second-stage test in the 10% of cases for which the model yields a risk of malignancy closest to its risk cut-off will improve specificity without substantially decreasing sensitivity. However, none of the models tested proved suitable as a second-stage test in tumors where subjective evaluation yielded an uncertain result.

Mathematical Models to Discriminate Between Benign and Malignant Adnexal Masses: Potential Diagnostic Improvement Using Ovarian HistoScanning

Purpose:

Accurate preoperative clinical assessment of adnexal masses can optimize outcomes by ensuring appropriate and timely surgery. This article addresses whether a new technology, ovarian HistoScanning, has an additional diagnostic value in mathematical models developed for the differential diagnosis of adnexal masses.

Patients and Methods:

Transvaginal sonography-based morphological variables were obtained through blinded analysis of archived images in 199 women enrolled in a prospective study to assess the performance of ovarian HistoScanning. Logistic regression (LR) and neural network (NN) models including these variables and clinical and patient data along with the HistoScanning score (HSS) (range, 0-125; based on mathematical algorithms) were developed in a learning set (60% patients). The remaining 40% patients (evaluation set) were used to assess model performance.

Results:

Of all morphological and clinical variables tested, serum CA-125, presence of a solid component, and HSS were most significant and used to develop the LR model. The NN model included all variables. The novel variable, HSS, offered significant improvement in the LR and NN models' performance. The LR and NN models in an independent evaluation set were found to have area under the receiver operating characteristic curve = 0.97 (95% confidence interval [CI], 94-99) and 0.93 (95% CI, 88-98), sensitivities = 83% (95% CI, 71%-91%) and 80% (95% CI, 67%-89%), and specificities = 98% (95% CI, 89%-99%) and 86% (95% CI, 72%-95%), respectively. In addition, these models showed an improved performance when compared with 3 other existing models (allP< 0.05).

Conclusions:

This initial report shows a clear benefit of including ovarian HistoScanning into mathematical models used for discriminating benign from malignant ovarian masses. These models may be specifically helpful to the less experienced examiner. Future research should assess performance of these models in prospective clinical trials in different populations.

Characterization of complex adnexal masses: value of adding perfusion- and diffusion-weighted MR imaging to conventional MR imaging

PURPOSE

To retrospectively determine the value of adding perfusion-weighted (PW) and diffusion-weighted (DW) sequences to a conventional magnetic resonance (MR) imaging protocol to differentiate benign from malignant tumors.

MATERIALS AND METHODS

The institutional ethics committee approved this retrospective study and waived the requirement to obtain informed consent. MR images in 87 women (age range, 25-87 years) who underwent imaging before surgery for complex adnexal masses-excluding endometriomas and cystic teratomas-were analyzed. Conventional morphologic, perfusion, and diffusion MR criteria of malignancy were recorded. Three independent observers reviewed images in four steps: conventional MR images alone, conventional MR images and PW images combined, conventional MR images and DW images combined, and conventional, PW, and DW MR images combined. Receiver operating characteristic curve analysis was performed to compare the results of the readings. A recursive partitioning model was built to establish a multivariate decision tree.

RESULTS

There was almost perfect agreement for lesion characterization regardless of the reader experiment or step considered (κ = 0.811-0.929). Area under the receiver operating characteristic curve values were higher for conventional and DW images combined, conventional and PW images combined, and conventional, DW, and PW images combined compared with conventional MR images alone (P < .05). For all readers, the accuracy of conventional, PW, and DW imaging combined was higher than that of conventional MR imaging alone for benign masses (P < .01) but not for malignant masses (P = .24). The addition of both PW and DW images led to a correct change in the diagnosis in 19% (11 of 57 patients), 23% (13 of 57 patients), and 24% (14 of 57 patients) of cases for readers 1, 2, and 3, respectively, with no incorrect changes. Conventional, PW, and DW MR imaging criteria were combined to generate a decision tree giving an accuracy of 95%.

CONCLUSION

The addition of PW and DW sequences to a conventional MR imaging protocol improved the diagnostic accuracy in the characterization of complex adnexal masses.

Simple ultrasound rules to distinguish between benign and malignant adnexal masses before surgery: prospective validation by IOTA group

OBJECTIVES

To prospectively assess the diagnostic performance of simple ultrasound rules to predict benignity/malignancy in an adnexal mass and to test the performance of the risk of malignancy index, two logistic regression models, and subjective assessment of ultrasonic findings by an experienced ultrasound examiner in adnexal masses for which the simple rules yield an inconclusive result.

DESIGN

Prospective temporal and external validation of simple ultrasound rules to distinguish benign from malignant adnexal masses. The rules comprised five ultrasonic features (including shape, size, solidity, and results of colour Doppler examination) to predict a malignant tumour (M features) and five to predict a benign tumour (B features). If one or more M features were present in the absence of a B feature, the mass was classified as malignant. If one or more B features were present in the absence of an M feature, it was classified as benign. If both M features and B features were present, or if none of the features was present, the simple rules were inconclusive.

SETTING

19 ultrasound centres in eight countries.

PARTICIPANTS

1938 women with an adnexal mass examined with ultrasound by the principal investigator at each centre with a standardised research protocol. Reference standard Histological classification of the excised adnexal mass as benign or malignant.

MAIN OUTCOME MEASURES

Diagnostic sensitivity and specificity.

RESULTS

Of the 1938 patients with an adnexal mass, 1396 (72%) had benign tumours, 373 (19.2%) had primary invasive tumours, 111 (5.7%) had borderline malignant tumours, and 58 (3%) had metastatic tumours in the ovary. The simple rules yielded a conclusive result in 1501 (77%) masses, for which they resulted in a sensitivity of 92% (95% confidence interval 89% to 94%) and a specificity of 96% (94% to 97%). The corresponding sensitivity and specificity of subjective assessment were 91% (88% to 94%) and 96% (94% to 97%). In the 357 masses for which the simple rules yielded an inconclusive result and with available results of CA-125 measurements, the sensitivities were 89% (83% to 93%) for subjective assessment, 50% (42% to 58%) for the risk of malignancy index, 89% (83% to 93%) for logistic regression model 1, and 82% (75% to 87%) for logistic regression model 2; the corresponding specificities were 78% (72% to 83%), 84% (78% to 88%), 44% (38% to 51%), and 48% (42% to 55%). Use of the simple rules as a triage test and subjective assessment for those masses for which the simple rules yielded an inconclusive result gave a sensitivity of 91% (88% to 93%) and a specificity of 93% (91% to 94%), compared with a sensitivity of 90% (88% to 93%) and a specificity of 93% (91% to 94%) when subjective assessment was used in all masses.

CONCLUSIONS

The use of the simple rules has the potential to improve the management of women with adnexal masses. In adnexal masses for which the rules yielded an inconclusive result, subjective assessment of ultrasonic findings by an experienced ultrasound examiner was the most accurate diagnostic test; the risk of malignancy index and the two regression models were not useful.

Ovarian cancer prediction in adnexal masses using ultrasound-based logistic regression models: a temporal and external validation study by the IOTA group

OBJECTIVES

The aims of the study were to temporally and externally validate the diagnostic performance of two logistic regression models containing clinical and ultrasound variables in order to estimate the risk of malignancy in adnexal masses, and to compare the results with the subjective interpretation of ultrasound findings carried out by an experienced ultrasound examiner ('subjective assessment').

METHODS

Patients with adnexal masses, who were put forward by the 19 centers participating in the study, underwent a standardized transvaginal ultrasound examination by a gynecologist or a radiologist specialized in ultrasonography. The examiner prospectively collected information on clinical and ultrasound variables, and classified each mass as benign or malignant on the basis of subjective evaluation of ultrasound findings. The gold standard was the histology of the mass with local clinicians deciding whether to operate on the basis of ultrasound results and the clinical picture. The models' ability to discriminate between malignant and benign masses was assessed, together with the accuracy of the risk estimates.

RESULTS

Of the 1938 patients included in the study, 1396 had benign, 373 had primary invasive, 111 had borderline malignant and 58 had metastatic tumors. On external validation (997 patients from 12 centers), the area under the receiver-operating characteristics curve (AUC) for a model containing 12 predictors (LR1) was 0.956, for a reduced model with six predictors (LR2) was 0.949 and for subjective assessment was 0.949. Subjective assessment gave a positive likelihood ratio of 11.0 and a negative likelihood ratio of 0.14. The corresponding likelihood ratios for a previously derived probability threshold (0.1) were 6.84 and 0.09 for LR1, and 6.36 and 0.10 for LR2. On temporal validation (941 patients from seven centers), the AUCs were 0.945 (LR1), 0.918 (LR2) and 0.959 (subjective assessment).

CONCLUSIONS

Both models provide excellent discrimination between benign and malignant masses. Because the models provide an objective and reasonably accurate risk estimation, they may improve the management of women with suspected ovarian pathology.

Value of ultrasonographic detection of normal ovarian tissue in the differential diagnosis of adnexal masses in pediatric patients

OBJECTIVE

The aim of the study was to evaluate whether the presence of normal ovarian tissue, the 'ovarian crescent sign' (OCS), could assist in the differential diagnosis between benign and malignant adnexal masses in young patients.

METHODS

This was a prospective observational study, from March 2004 to January 2006, which included 98 patients younger than 20 years of age (including two with bilateral tumors) with an ultrasonographic diagnosis of an adnexal mass. Morphological assessment using the Ueland index was performed in each case. Patients were also systematically examined for the presence of the OCS and a comparison was made with the Ueland index. All findings in surgically treated patients were compared with the final histological diagnosis.

RESULTS

There were 100 adnexal masses: 90 were benign and 10 were malignant. Forty-eight were managed expectantly and 52, including 17 cases of adnexal torsion, underwent surgical treatment. The OCS was found in 65 (72%) benign adnexal masses and in one (10%) non-invasive malignant tumor. A Ueland index score of < 7 was found in 85 (94%) benign masses and in one (10%) non-invasive malignancy. The OCS was seen in 15 (45%) of 33 masses in premenarchal patients and in 51 (76%) of 67 masses in postmenarchal patients. The OCS was absent in 15 (88%) of the torsioned adnexal masses.

CONCLUSIONS

The presence of normal ovarian tissue adjacent to an ovarian mass is a useful morphological feature that can assist exclusion of a malignant tumor in pediatric and adolescent patients. When compared with the Ueland index, diagnostic sensitivity of the OCS is similar, but specificity is lower. The presence of the OCS is significantly less frequent in premenarchal patients than in postmenarchal patients.

Ultrasound methods to distinguish between malignant and benign adnexal masses in the hands of examiners with different levels of experience

OBJECTIVES

To determine the effect of an ultrasound training course on the performance of pattern recognition when used by less experienced examiners and to compare the performance of pattern recognition, a logistic regression model and a scoring system to estimate the risk of malignancy between examiners with different levels of experience.

METHODS

Using ultrasound images of selected adnexal masses, two trainees classified the masses as benign or malignant by using pattern recognition both before and after they had attended a theoretical gynecological ultrasound course. They also classified the masses by using a logistic regression model and a scoring system, but only after they had attended the course. The performance of these three methods when they were used by the trainees was then compared with that when they were used by experts.

RESULTS

One hundred and sixty-five adnexal masses were included, of which 42% were malignant (21% invasive tumors and 21% borderline tumors). The area under the receiver-operating characteristics curve of pattern recognition when used by the trainees was similar before and after they had attended the course. Training decreased sensitivity (84% vs. 70% for Trainee 1, P = 0.004; 70% vs. 61% for Trainee 2, P = 0.058) and increased specificity (77% vs. 92% for Trainee 1, P = 0.001; 89% vs. 95% for Trainee 2, P = 0.058). The performance of pattern recognition was poorer in the hands of the trainees than in the hands of the experts. The sensitivities of the logistic regression model were 70% and 54% for the trainees vs. 83% for an expert (P = 0.020 and < 0.001, respectively) and the specificities were 84% and 94% vs. 89% (P = 0.25 and 0.59, respectively). The sensitivities of the scoring system were 59% and 54% for the trainees vs. 75% for the expert (P = 0.002 and < 0.001, respectively), and the specificities were 90% and 93% vs. 85% (P = 0.103 and 0.008, respectively).

CONCLUSION

Theoretical ultrasound teaching did not seem to improve the performance of pattern recognition in the hands of trainees. A logistic regression model and a scoring system to classify adnexal masses as benign or malignant perform less well when they were used by inexperienced examiners than when used by an expert. Before using a model or a scoring system, experience and/or proper training are likely to be of paramount importance if diagnostic performance is to be optimized.

Diagnostic accuracy of transvaginal ultrasound examination for assigning a specific diagnosis to adnexal masses

OBJECTIVES

To determine the sensitivity and specificity of subjective evaluation of gray-scale and Doppler ultrasound findings (here called pattern recognition) when used by experienced ultrasound examiners with regard to making a specific diagnosis of adnexal masses.

METHODS

Within the framework of a European multicenter study, the International Ovarian Tumor Analysis study, comprising nine ultrasound centers, women with at least one adnexal mass were examined with gray-scale and color Doppler ultrasonography by experienced ultrasound examiners. A standardized examination technique, and standardized terms and definitions were used. Using pattern recognition the examiners classified each mass as benign or malignant and suggested a specific diagnosis (e.g. dermoid cyst or endometrioma). The reference standard was the histology of the surgically removed adnexal tumors.

RESULTS

A total of 1066 women were included, of whom 800 had a benign mass and 266 a malignant mass. A specific diagnosis based on ultrasound findings was suggested in 899 (84%) tumors. The specificity was high for all diagnoses (range, 94-100%). The sensitivity was highest for benign teratoma/dermoid cysts (86%, 100/116), hydrosalpinges (86%, 18/21), peritoneal pseudocysts (80%, 4/5) and endometriomas (77%, 153/199), and lowest for functional cysts (17%, 4/24), paraovarian/parasalpingeal cysts (14%, 3/21), benign rare tumors (11%, 1/9), adenofibromas (8%, 3/39), simple cysts (6%, 1/18) and struma ovarii (0%, 0/5). The positive and negative likelihood ratios of pattern recognition with regard to dermoid cysts, hydrosalpinges and endometriomas were 68.2 and 0.14, 38.9 and 0.15, and 33.3 and 0.24, respectively. Dermoid cysts, hydrosalpinges, functional cysts, paraovarian cysts, peritoneal pseudocysts, fibromas/fibrothecomas and simple cysts were never misdiagnosed as malignancies by the ultrasound examiner, whereas more than 10% of inflammatory processes, adenofibromas and rare benign tumors including struma ovarii were misdiagnosed as malignancies.

CONCLUSIONS

Using subjective evaluation of gray-scale and Doppler ultrasound findings it is possible to make an almost conclusive diagnosis of a dermoid cyst, endometrioma and hydrosalpinx. Many other adnexal pathologies can be recognized but not confidently confirmed or excluded.

Adding a single CA 125 measurement to ultrasound imaging performed by an experienced examiner does not improve preoperative discrimination between benign and malignant adnexal masses

OBJECTIVES

To determine whether CA 125 measurement is superior to ultrasound imaging performed by an experienced examiner for discriminating between benign and malignant adnexal lesions, and to determine whether adding CA 125 to ultrasound examination improves diagnostic performance.

METHODS

This is a prospective multicenter study (International Ovarian Tumor Analysis (IOTA) study) conducted in nine European ultrasound centers in university hospitals. Of 1149 patients with an adnexal mass examined in the IOTA study, 83 were excluded. Of the remaining 1066 patients, 809 had CA 125 results available and were included. The patients underwent preoperative serum CA 125 measurements and transvaginal ultrasound examination by an experienced ultrasound examiner blinded to CA 125 values. The examiner classified each mass as certainly or probably benign, difficult to classify, or probably or certainly malignant. The outcome measure was the sensitivity and specificity with regard to malignancy of CA 125, ultrasound imaging and their combined use, the 'gold standard' being the histological diagnosis of the adnexal mass removed surgically within 120 days after the ultrasound examination.

RESULTS

There were 242 (30%) malignancies. For 534 tumors judged to be certainly benign or certainly malignant by the ultrasound examiner the sensitivity and specificity of ultrasound examination and CA 125 (> or =35 U/mL indicating malignancy) were 97% vs. 86% (95% CI of difference, 4.7-17.2) and 99% vs. 79% (95% CI of difference, 15.7-24.2); for 209 tumors judged probably benign or probably malignant, sensitivity and specificity were 81% vs. 57% (95% CI of difference, 12.3-36.0) and 91% vs. 74% (95% CI of difference, 8.5-25.7); for 66 tumors that were difficult to classify, sensitivity and specificity were 57% vs. 39% (95% CI of difference, -9.7 to 41.1) and 74% vs. 67% (95% CI of difference, -14.6 to 27.7). Diagnostic performance deteriorated when CA 125 was used as a second-stage test after ultrasound examination.

CONCLUSIONS

Specialist ultrasound examination is superior to CA 125 for preoperative discrimination between benign and malignant adnexal masses, irrespective of the diagnostic confidence of the ultrasound examiner; adding CA 125 to ultrasound does not improve diagnostic performance. Our results indicate that greater investment in education and training in gynecological ultrasound imaging would be of value.

The accuracy of risk scores in predicting ovarian malignancy: a systematic review

OBJECTIVE

To perform a systematic review of the literature on the accuracy of prediction models in the preoperative assessment of adnexal masses.

DATA SOURCES

Studies were identified through the MEDLINE and EMBASE databases from inception to March 2008. The MEDLINE search was performed using the keywords ["ovarian neoplasms"[MeSH] NOT "therapeutics"[MeSH] AND "model"] and ["ovarian neoplasms"[MeSH] NOT "therapeutics"[MeSH] AND "prediction"]. The Embase search was performed using the keywords [ovary tumor AND prediction], [ovary tumor AND Mathematical model], and [ovary tumor AND statistical model].

METHODS OF STUDY SELECTION

The search detected 1,161 publications; from the cross-references, another 116 studies were identified. Language restrictions were not applied. Eligible studies contained data on the accuracy of models predicting the risk of malignancy in ovarian masses. Models were required to combine at least two parameters.

TABULATION, INTEGRATION, AND RESULTS

Two independent reviewers selected studies and extracted study characteristics, study quality, and test accuracy. There were 109 accuracy studies that met the selection criteria. Accuracy data were used to form two-by-two contingency tables of the results of the risk score compared with definitive histology. We used bivariate meta-analysis to estimate pooled sensitivities and specificities and to fit summary receiver operating characteristic curves.Studies included in our analysis reported on 83 different prediction models. The model developed by Sassone was the most evaluated prediction model. All models has acceptable sensitivity and specificity. However, the Risk of Malignancy Index I and the Risk of Malignancy Index II, which use the product of the serum CA 125 level, an ultrasound scan result, and the menopausal state, were the best predictors. When 200 was used as the cutoff level, the pooled estimate for sensitivity was 78% for a specificity of 87%.

CONCLUSION

Based on our review, the Risk of Malignancy Index should be the prediction model of choice in the preoperative assessment of the adnexal mass.

A scoring system to differentiate malignant from benign masses in specific ultrasound-based subgroups of adnexal tumors

OBJECTIVE

To investigate if the prediction of malignant adnexal masses can be improved by considering different ultrasound-based subgroups of tumors and constructing a scoring system for each subgroup instead of using a risk estimation model applicable to all tumors.

METHODS

We used a multicenter database of 1573 patients with at least one persistent adnexal mass. The masses were categorized into four subgroups based on their ultrasound appearance: (1) unilocular cyst; (2) multilocular cyst; (3) presence of a solid component but no papillation; and (4) presence of papillation. For each of the four subgroups a scoring system to predict malignancy was developed in a development set consisting of 754 patients in total (respective numbers of patients: (1) 228; (2) 143; (3) 183; and (4) 200). The subgroup scoring system was then tested in 312 patients and prospectively validated in 507 patients. The sensitivity and specificity, with regard to the prediction of malignancy, of the scoring system were compared with that of the subjective evaluation of ultrasound images by an experienced examiner (pattern recognition) and with that of a published logistic regression (LR) model for the calculation of risk of malignancy in adnexal masses. The gold standard was the pathological classification of the mass as benign or malignant (borderline, primary invasive, or metastatic).

RESULTS

In the prospective validation set, the sensitivity of pattern recognition, the LR model and the subgroup scoring system was 90% (129/143), 95% (136/143) and 88% (126/143), respectively, and the specificity was 93% (338/364), 74% (270/364) and 90% (329/364), respectively.

CONCLUSIONS

In the hands of experienced ultrasound examiners, the subgroup scoring system for diagnosing malignancy has a performance that is similar to that of pattern recognition, the latter method being the best diagnostic method currently available. The scoring system is less sensitive but more specific than the LR model.

Comparison of the risk of malignancy index and self-constructed logistic regression models in preoperative evaluation of adnexal masses

OBJECTIVE

The aim of this study was to evaluate women with adnexal masses in the preoperative period by creating 2 logistic regression models, 1 including sonographic morphologic characteristics and the other including both morphologic and color Doppler characteristics, to compare the diagnostic accuracy of these 2 models with the risk of malignancy index (RMI).

METHODS

This prospective study included 38 malignant, 7 borderline, and 244 benign ovarian masses. The menopausal status, presence of septa, presence of papillary projections, location of the tumor, presence of ascites, presence of metastases, cancer antigen 125 level, tumor volume, septa thickness, and percentage of the solid component were included in the initial analysis. A second regression analysis was performed with the addition of Doppler parameters (location of blood flow and lowest resistive index) in the data set. Diagnostic performance of the 2 regression models and RMI were described and compared by generating receiver operating characteristic curves for each model.

RESULTS

The area under the curve values for the morphologic model (model 1), Doppler model (model 2), and RMI were 0.907, 0.971, and 0.889, respectively. Significance levels of model 1 and the RMI were similar (P = .23), whereas model 2 had a significantly higher area under the curve compared with both model 1 (P = .037) and the RMI (P = .018).

CONCLUSIONS

The addition of Doppler parameters in the regression model significantly increases the predictive performance. Nevertheless, in low-resource settings, the RMI remains the method of choice for distinguishing adnexal masses and referral to gynecologic oncology clinics.

Imaging of gynecological disease (3): clinical and ultrasound characteristics of granulosa cell tumors of the ovary

OBJECTIVES

To describe the clinical and ultrasound characteristics of granulosa cell tumors (GCTs) of the ovary, and to define the ultrasound appearance of GCTs based on pattern recognition.

METHODS

Databases of four gynecological ultrasound centers were searched to identify patients with histologically proven GCTs who had undergone a standard preoperative ultrasound examination.

RESULTS

A total of 23 women with confirmed GCT were identified. Twelve (52%) women were postmenopausal, nine (39%) were of fertile age and two (9%) were prepubertal. Clinical symptoms were abdominal distension (7/23, 30%), pain (5/23, 22%) and irregular vaginal bleeding (6/23, 26%). Seven patients (30%) were asymptomatic. Endometrial pathology was found in 54% (7/13) of the patients from whom endometrial biopsies were taken. On ultrasound scan 12/23 (52%) masses were multilocular-solid, 9/23 (39%) were purely solid, one mass (4%) was unilocular-solid and one mass was multilocular (4%). Multilocular and multilocular-solid cysts typically contained large numbers of small locules (> 10). The echogenicity of the cyst content was most often mixed (6/16, 38%) or low level (7/16, 44%). Papillary projections were found in only four women (17%). The GCTs were large tumors with a median largest diameter of 102 (range, 37-242) mm and manifested moderate or high color content at color Doppler examination (color score 3 in 13/23 tumors (57%); color score 4 in 8/23 tumors (35%)).

CONCLUSIONS

At ultrasound examination, most GCTs are large multilocular-solid masses with a large number of locules, or solid tumors with heterogeneous echogenicity of the solid tissue. Hemorrhagic components are common and increased vascularity is demonstrated at color/power Doppler ultrasound examination. The hyperestrogenic state that is created by the tumor often causes endometrial pathology with bleeding problems as a typical associated symptom.

Discrimination between benign and malignant adnexal masses by specialist ultrasound examination versus serum CA-125

BACKGROUND

Subjective evaluation of gray-scale and Doppler ultrasound findings (i.e., pattern recognition) by an experienced examiner and preoperative serum levels of CA-125 can both discriminate benign from malignant adnexal (i.e., ovarian, paraovarian, or tubal) masses. We compared the diagnostic performance of these methods in a large multicenter study.

METHODS

In a prospective multicenter study--the International Ovarian Tumor Analysis--1066 women with a persistent adnexal mass underwent transvaginal gray-scale and color Doppler ultrasound examinations by an experienced examiner within 120 days of surgery. Pattern recognition was used to classify a mass as benign or malignant. Of these women, 809 also had blood collected preoperatively for measurement of serum CA-125. Various levels of CA-125 were used as cutoffs to classify masses. Results from both assays were then compared with histologic findings after surgery.

RESULTS

Pattern recognition correctly classified 93% (95% confidence interval [CI] = 90.9% to 94.6%) of the tumors as benign or malignant. Serum CA-125 correctly classified at best 83% (95% CI = 80.3% to 85.6%) of the masses. Histologic diagnoses that were most often misclassified by CA-125 were fibroma, endometrioma, and abscess (false-positive results) and borderline tumor (false-negative results). Pattern recognition correctly classified 86% (95% CI = 81.1% to 90.4%) of masses of these four histologic types as being benign or malignant, whereas a serum CA-125 at a cutoff of 30 U/mL correctly classified 41% (95% CI = 34.4% to 47.5%) of them. Pattern recognition assigned a correct specific histologic diagnosis to 333 (59%, 95% CI = 54.5% to 62.8%) of the 567 benign lesions.

CONCLUSION

Pattern recognition was superior to serum CA-125 for discrimination between benign and malignant adnexal masses.

Contribution of morphological assessment of the vessel tree by three-dimensional ultrasound to a correct diagnosis of malignancy in ovarian masses

OBJECTIVE

To determine whether subjective evaluation of the morphology of the vessel tree of ovarian tumors, as depicted by three-dimensional (3D) power Doppler ultrasound, can discriminate between benign and malignant ovarian tumors, and whether it improves characterization compared with using gray-scale ultrasound imaging alone.

METHODS

A consecutive series of 104 women scheduled for surgical removal of an ovarian mass were examined with transvaginal two-dimensional (2D) gray-scale and 3D power Doppler ultrasound. Predetermined vessel characteristics, e.g. density of vessels, branching, caliber changes and tortuosity, were evaluated in 360 degrees rotating 3D images of the vessel tree of the tumor. Ultrasound results were compared with those of the histology of the surgical specimens. Univariate and multivariate logistic regression were used.

RESULTS

There were 77 benign tumors, six borderline tumors and 21 invasive malignancies. All vascular features differed significantly between benign and malignant tumors. The areas under their receiver-operating characteristics (ROC) curves (AUCs) were in the range 0.61-0.83. The AUC of a logistic regression model containing three gray-scale ultrasound variables was 0.98. This model correctly classified all malignancies, with a false-positive rate of 10% (8/77). Adding branching of vessels in the whole tumor to the gray-scale model yielded an AUC of 0.99 and resulted in all malignancies and an additional four benign tumors being correctly classified.

CONCLUSIONS

Subjective evaluation of the morphology of the vessel tree, as depicted by 3D power Doppler ultrasound, can be used to discriminate between benign and malignant ovarian tumors, but adds little to gray-scale ultrasound imaging in an ordinary population of tumors.

Value of preoperative ultrasound examination in the selection of women with adnexal masses for laparoscopic surgery

OBJECTIVES

To assess the value of preoperative ultrasound examination in predicting the feasibility of intermediate-level laparoscopic surgery for benign adnexal masses.

METHODS

Symptomatic women with a clinical or ultrasound diagnosis of adnexal mass were offered a detailed transvaginal ultrasound scan in order to assess the feasibility of laparoscopic cystectomy/oophorectomy. In all cases an attempt was made to establish a likely histological diagnosis using the pattern recognition method. The selection criteria for laparoscopic surgery were: no ultrasound features suggestive of ovarian cancer, predominantly cystic lesion with no solid foci > 5 cm in mean diameter, no evidence of severe pelvic endometriosis or severe pelvic adhesions and dermoid cyst < 10 cm in mean diameter. Laparoscopic surgery was classified as successful if the mass was removed completely without resorting to a laparotomy.

RESULTS

One hundred and forty-three women were diagnosed with a total of 162 adnexal cysts. The final dataset consisted of 137 women (with 153 lesions), 113 (82.5%) of whom were selected for laparoscopy and 24 (17.5%) for laparotomy. On histological examination 152 (99.3%) cysts were benign and the remaining one (0.7%) was borderline. The operation was successfully completed laparoscopically in 107/113 (94.7%) cases. The preoperative ultrasound assessment predicted the successful outcome of laparoscopic surgery with a sensitivity of 98% (95% CI, 94-99%), specificity of 79% (95% CI, 60-90%), positive predictive value of 95% (95% CI, 89-98%), positive likelihood ratio of 4.58 (95% CI, 2.25-9.32) and negative likelihood ratio of 0.02 (95% CI, 0.01-0.09).

CONCLUSIONS

A detailed preoperative transvaginal ultrasound examination is a helpful tool for assessing the feasibility of intermediate-level laparoscopic surgery in women with benign adnexal lesions.

External validation of mathematical models to distinguish between benign and malignant adnexal tumors: a multicenter study by the International Ovarian Tumor Analysis Group

PURPOSE

Several scoring systems have been developed to distinguish between benign and malignant adnexal tumors. However, few of them have been externally validated in new populations. Our aim was to compare their performance on a prospectively collected large multicenter data set.

EXPERIMENTAL DESIGN

In phase I of the International Ovarian Tumor Analysis multicenter study, patients with a persistent adnexal mass were examined with transvaginal ultrasound and color Doppler imaging. More than 50 end point variables were prospectively recorded for analysis. The outcome measure was the histologic classification of excised tissue as malignant or benign. We used the International Ovarian Tumor Analysis data to test the accuracy of previously published scoring systems. Receiver operating characteristic curves were constructed to compare the performance of the models.

RESULTS

Data from 1,066 patients were included; 800 patients (75%) had benign tumors and 266 patients (25%) had malignant tumors. The morphologic scoring system used by Lerner gave an area under the receiver operating characteristic curve (AUC) of 0.68, whereas the multimodal risk of malignancy index used by Jacobs gave an AUC of 0.88. The corresponding values for logistic regression and artificial neural network models varied between 0.76 and 0.91 and between 0.87 and 0.90, respectively. Advanced kernel-based classifiers gave an AUC of up to 0.92.

CONCLUSION

The performance of the risk of malignancy index was similar to that of most logistic regression and artificial neural network models. The best result was obtained with a relevance vector machine with radial basis function kernel. Because the models were tested on a large multicenter data set, results are likely to be generally applicable.

Inclusion of CA-125 does not improve mathematical models developed to distinguish between benign and malignant adnexal tumors

PURPOSE

To test the value of serum CA-125 measurements alone or as part of a multimodal strategy to distinguish between malignant and benign ovarian tumors before surgery based on a large prospective multicenter study (International Ovarian Tumor Analysis).

PATIENTS AND METHODS

Patients with at least one persistent ovarian mass preoperatively underwent transvaginal ultrasonography using gray scale imaging to assess tumor morphology and color Doppler imaging to obtain indices of blood flow.

RESULTS

Data from 809 patients recruited from nine centers were included in the analysis; 567 patients (70%) had benign tumors and 242 (30%) had malignant tumors-of these 152 were primary invasive (62.8%), 52 were borderline malignant (21.5%), and 38 were metastatic (15.7%). A logistic regression model including CA-125 (M2) resulted in an area under the receiver operating characteristic curve (AUC) of 0.934 and did not outperform a published (M1) without serum CA-125 information (AUC, 0.936). Specifically designed new models including CA-125 for premenopausal women (M3) and for postmenopausal women (M4) did not perform significantly better than the model without CA-125 (M1; AUC, 0.891 v AUC, 0.911 and AUC, 0.975 v AUC, 0.949, respectively). In postmenopausal patients, serum CA-125 alone (AUC, 0.920) and the risk of malignancy index (AUC, 0.924) performed very well. Results were very similar when the models were prospectively tested on a group of 345 new patients with adnexal masses of whom 126 had malignant tumors (37%).

CONCLUSION

Adding information on CA-125 to clinical information and ultrasound information does not improve discrimination of mathematical models between benign and malignant adnexal masses.

A Practical Approach to the Ultrasound Characterization of Adnexal Masses

Because pelvic ultrasound is commonly used to evaluate adnexal masses, it is important to understand the most useful sonographic features for predicting benign and malignant masses. Determining whether an adnexal mass is of ovarian or extraovarian origin is key in arriving at the most likely diagnosis. Most adnexal masses are benign, and each of the most common benign ovarian lesions has a typical sonographic appearance. Additionally, most malignant ovarian neoplasms have a solid component with detectable flow by Doppler ultrasound, allowing one to strongly suggest the diagnosis. We will review an approach to the ultrasound diagnosis of adnexal masses that progresses through a series of 4 questions to help lead one to the most likely diagnosis.

Preoperative diagnosis of ovarian tumors using Bayesian kernel-based methods

OBJECTIVES

To develop flexible classifiers that predict malignancy in adnexal masses using a large database from nine centers.

METHODS

The database consisted of 1066 patients with at least one persistent adnexal mass for which a large amount of clinical and ultrasound data were recorded. The outcome of interest was the histological classification of the adnexal mass as benign or malignant. The outcome was predicted using Bayesian least squares support vector machines in comparison with relevance vector machines. The models were developed on a training set (n=754) and tested on a test set (n=312).

RESULTS

Twenty-five percent of the patients (n=266) had a malignant tumor. Variable selection resulted in a set of 12 variables for the models: age, maximal diameter of the ovary, maximal diameter of the solid component, personal history of ovarian cancer, hormonal therapy, very strong intratumoral blood flow (i.e. color score 4), ascites, presumed ovarian origin of tumor, multilocular-solid tumor, blood flow within papillary projections, irregular internal cyst wall and acoustic shadows. Test set area under the receiver-operating characteristics curve (AUC) for all models exceeded 0.940, with a sensitivity above 90% and a specificity above 80% for all models. The least squares support vector machine model with linear kernel performed very well, with an AUC of 0.946, 91% sensitivity and 84% specificity. The models performed well in the test sets of all the centers.

CONCLUSIONS

Bayesian kernel-based methods can accurately separate malignant from benign masses. The robustness of the models will be investigated in future studies.

Accuracy of ultrasound subjective 'pattern recognition' for the diagnosis of borderline ovarian tumors

OBJECTIVES

To assess the value of pattern recognition for the preoperative ultrasound diagnosis of borderline ovarian tumors (BOTs).

METHODS

This was a prospective study of women who were referred to our regional cancer center with the diagnosis of an adnexal mass on a Level II (routine) gynecological ultrasound scan. Women with lesions of uncertain nature were referred for a Level III (expert) ultrasound scan in our tertiary center. The tumor pattern recognition method was used to differentiate between various types of ovarian tumors. Morphological features suggestive of BOTs were: unilocular cyst with a positive ovarian crescent sign and extensive papillary projections arising from the inner wall, or a cyst with a well defined multilocular nodule. The ultrasound findings were compared with the final histological diagnosis.

RESULTS

A total of 224 women with an adnexal mass of uncertain nature were referred for an expert scan, 166 (74.1%) of whom underwent surgery. In this group of women the final histological diagnoses were: 99 (60%) benign lesions, 32 (19%) invasive ovarian cancer and 35 (21%) BOTs. Using pattern recognition combining the different morphological features, a correct preoperative diagnosis of BOT was made in 24/35 (68.6%) women: area under the receiver-operating characteristics curve 0.812 (standard error 0.049; 95% CI, 0.716-0.908), sensitivity 0.69 (95% CI, 0.52-0.81), specificity 0.94 (95% CI, 0.88-0.97), positive likelihood ratio 11.3 (95% CI, 5.53-22.8) and negative likelihood ratio 0.34 (95% CI, 0.21-0.55).

CONCLUSIONS

Ultrasound diagnosis of BOTs is highly specific. However, typical features are absent in one-third of cases, which are typically misdiagnosed as benign lesions.

Numerous intracystic floating balls as a sonographic feature of benign cystic teratoma: report of 5 cases

OBJECTIVE

The purpose of this series was to describe the unusual but unique sonographic pattern of mature cystic teratoma.

METHODS

Five patients of reproductive age with clinical manifestations of a pelvic mass were evaluated with sonography for treatment planning.

RESULTS

All 5 cases showed the similar sonographic pattern of a large cystic tumor filled with multiple echogenic spherical structures floating in the cystic background. Of the 5 patients, 3 had rather large balls varying in size between 1 and 4 cm in the same tumor masses, whereas the other 2 had numerous smaller balls of about 0.5 cm in diameter. The numerous crowded very small echogenic balls in the last 2 cases mimicked solid nodules representing malignancy. However, there was no vascularization in the balls, which suggested a benign nature. The postoperative pathologic diagnosis was mature cystic teratoma without any malignant component in all cases.

CONCLUSIONS

The sonographic feature of intracystic floating echogenic balls is probably pathognomonic for mature teratoma and is easily detected in most cases. Color Doppler sonography is helpful in differentiating these benign nodules (small balls) from malignant tumors.

Imaging in gynecology

This chapter summarizes the diagnostic performance (sensitivity, specificity, positive and negative likelihood ratios) of ultrasound, computer tomography, and magnetic resonance imaging in the diagnosis of various gynecological diseases and tumors. Positron emission tomography is not discussed. Imaging in infertility, in the diagnosis of Mullerian duct anomalies and in gynecological oncology (staging of gynecological cancers, diagnosis of recurrence of gynecological cancer, diagnosis of trophoblastic tumors) is not dealt with. Ultrasound is the first-line imaging method for discrimination between viable intrauterine pregnancy, miscarriage and tubal pregnancy in women with bleeding and/or pain in early pregnancy, for discrimination between benign and malignant adnexal masses and for making a specific diagnosis in adnexal tumors (e.g. dermoid cyst, endometrioma, hemorrhagic corpus luteum, etc.), for diagnosing intracavitary uterine pathology in women with bleeding problems, and for confirming or refuting pelvic pathology in women with pelvic pain. Magnetic resonance imaging can have a role as a secondary test in the diagnosis of adenomyosis, 'deep endometriosis' (e.g. endometriosis in the rectovaginal septum or in the uterosacral ligaments), and in the diagnosis of extremely rare types of ectopic pregnancy (e.g. in the spleen, liver or retroperitoneum).

Practical Approach to the Adnexal Mass

Gynecologic sonography has matured into a highly effective and accurate tool enabling confident diagnosis of a variety of adnexal masses. Using a practical evidence-based approach, sonologists are well equipped to differentiate expected findings in the normal ovary from pathologic entities and can often generate specific conclusions regarding the cause of an adnexal mass. Mastery of the diagnostic strategies to use when an adnexal mass is identified and the sonographic patterns of various types of adnexal pathology contributes greatly to the proper and cost-effective care of a woman with an adnexal mass.

A comparative study of the risk of malignancy index and the ovarian crescent sign for the diagnosis of invasive ovarian cancer

OBJECTIVE

To compare the value of the risk of malignancy index (RMI) and the ovarian crescent sign (OCS) in the diagnosis of ovarian malignancy.

METHODS

This was a prospective observational study of women with ultrasonographic diagnosis of an ovarian cyst. The RMI was calculated in all cases using a previously published formula (RMI = U (ultrasound score) x M (menopausal status) x serum CA125 (kU/L)). A value > 200 was considered to be diagnostic of ovarian cancer. The OCS was defined as a rim of visible healthy ovarian tissue in the ipsilateral ovary. Its absence was taken as being diagnostic of invasive cancer.

RESULTS

A total of 106 consecutive women were included in the study, of whom 92 (86.8%) had a benign ovarian tumor, five (4.7%) had borderline lesions and nine (8.5%) had an invasive ovarian cancer. The absence of an OCS diagnosed invasive ovarian cancer with a sensitivity of 100% (95% CI, 70-100%), specificity of 93% (95% CI, 86-96%), positive predictive value (PPV) of 56%, negative predictive value (NPV) of 100% and positive likelihood ratio (LR+) of 13.86 (95% CI, 6.79-28.29). This compared favorably with a sensitivity of 89% (95% CI, 57-98%), specificity of 92% (95% CI, 85-96%), PPV of 50%, NPV of 99% and LR+ of 10.78 (95% CI, 5.34-21.77), which were achieved using RMI > 200 (P < 0.01).

CONCLUSIONS

The RMI and the OCS are useful tests for discriminating between invasive and non-invasive ovarian tumors. The application of these tests in a sequential manner might improve the overall accuracy of ovarian cancer diagnosis.

Logistic regression model to distinguish between the benign and malignant adnexal mass before surgery: a multicenter study by the International Ovarian Tumor Analysis Group

PURPOSE

To collect data for the development of a more universally useful logistic regression model to distinguish between a malignant and benign adnexal tumor before surgery.

PATIENTS AND METHODS

Patients had at least one persistent mass. More than 50 clinical and sonographic end points were defined and recorded for analysis. The outcome measure was the histologic classification of excised tissues as malignant or benign.

RESULTS

Data from 1,066 patients recruited from nine European centers were included in the analysis; 800 patients (75%) had benign tumors and 266 (25%) had malignant tumors. The most useful independent prognostic variables for the logistic regression model were as follows: (1) personal history of ovarian cancer, (2) hormonal therapy, (3) age, (4) maximum diameter of lesion, (5) pain, (6) ascites, (7) blood flow within a solid papillary projection, (8) presence of an entirely solid tumor, (9) maximal diameter of solid component, (10) irregular internal cyst walls, (11) acoustic shadows, and (12) a color score of intratumoral blood flow. The model containing all 12 variables (M1) gave an area under the receiver operating characteristic curve of 0.95 for the development data set (n = 754 patients). The corresponding value for the test data set (n = 312 patients) was 0.94; and a probability cutoff value of .10 gave a sensitivity of 93% and a specificity of 76%.

CONCLUSION

Because the model was constructed from multicenter data, it is more likely to be generally applicable. The effectiveness of the model will be tested prospectively at different centers.

Differentiation of small adnexal masses based on morphologic characteristics of transvaginal sonographic imaging: a multicenter study

OBJECTIVE

The purpose of this study was to assess the diagnostic accuracy of transvaginal sonographic examination of small adnexal masses by simple descriptive sonographic scoring.

METHODS

In a prospective multicenter study, 4 teaching hospitals and 2 regional hospitals with homogeneous standard sonographic equipment and operator experience recruited 677 consecutive patients with small adnexal masses of less than 5 cm. Morphologic scoring was obtained for each mass and recorded. The management of the mass was based on local protocols. The minimal requirement was that surgery had to be performed for complex masses scoring 8 or higher, and follow-up of at least 12 months had to be performed and recorded for patients not admitted to surgery. Sonographic results were compared with pathologic reports and follow-up findings.

RESULTS

Fifty-two malignant tumors (19 borderline, 15 stage I-II, 15 stage III-IV, 2 tubal carcinomas, and 1 ovarian lymphoma), 243 benign tumors at pathologic examination, and 382 masses defined as benign according to follow-up findings were observed. Malignant tumors had a significantly higher mean +/- SD morphologic score (11.2 +/- 2.7) than benign masses (6.2 +/- 2.5) (P = .001). No difference was observed in the scoring assignment of malignant masses in different centers (P = .56). With a score of 8 or higher, the likelihood ratio was 3.61 (95% confidence interval, 3.09-4.21); sensitivity, 92%; specificity, 76.9%; and positive predictive value, 25.6%.

CONCLUSIONS

Our results provide evidence that descriptive morphologic scoring may overcome the subjectivity of interpretation of morphologic characteristics in small masses, and, at the same time, it can incorporate criteria to avoid simplistic description of a complex mass.

The role of ultrasound evaluation in the detection of early-stage epithelial ovarian cancer

OBJECTIVE

Epithelial ovarian cancer kills more women than all other gynecologic malignancies combined because of our inability to detect early-stage disease. Ultrasonography has demonstrated usefulness in the detection of ovarian cancer in asymptomatic women, but its value for the detection of early-stage epithelial ovarian cancer in women of increased risk is uncertain. We examined the usefulness of sonography in the detection of early-stage epithelial ovarian cancer in asymptomatic high-risk women who participated in the National Ovarian Cancer Early Detection Program.

STUDY DESIGN

Only asymptomatic women of increased risk for the development of ovarian cancer with initial normal gynecologic and ultrasound examinations were eligible to participate in the institutional review board-approved National Ovarian Cancer Early Detection Program. Participants underwent comprehensive gynecologic and ultrasound examinations every 6 months. Increased risk includes women with at least 1 affected first-degree relative with ovarian cancer; a personal history of breast, ovarian, or colon cancer; > or =1 affected first- and second-degree relatives with breast and or ovarian cancer; inheritance of a breast cancer mutation from an affected family member, or membership within a recognized cancer syndrome.

RESULTS

The average age of the 4526 women who were evaluated was 46 years; 2610 women were premenopausal, and 1916 women were postmenopausal. A total of 12,709 scans have been performed since 1990. Visualization of both ovaries was noted in 98% of premenopausal and in 94% of postmenopausal women. Fourteen women had undergone unilateral salpingo-oophorectomy. Recall rates at less than the routine 6-month interval were 0.4% in the premenopausal and 0.3% in postmenopausal women. A total of 98 women with persistent adnexal masses were identified, and 49 invasive surgical procedures were performed that diagnosed 37 benign ovarian tumors and 12 gynecologic malignancies. All cancers were detected in asymptomatic women who had normal ultrasound and physical examinations 12 and 6 months before the cancer diagnosis. The detected malignancies were fallopian tube carcinoma (stage IIIC; n = 4 women), primary peritoneal carcinoma (n = 4 women; stage IIIA, 1 woman; stage IIIB, 2 women; stage IIIC, 1 woman), epithelial ovarian cancer (stages IIIA and IIIB; n = 2 women), and endometrial adenocarcinoma (stage IA; n = 2 women). Additionally 37 primary and 12 recurrent breast carcinomas were detected by physical examination. A total of 184 women with genetic predisposition (breast cancer positive) have undergone a prophylactic bilateral salpingo-oophorectomy; 23% of these procedures found atypical hyperplasia, and unexpectedly, 2 women (1%) were found to have stage III (A and B) primary peritoneal carcinoma.

CONCLUSION

This study demonstrates the limited value of diagnostic ultrasound examination as an independent modality for the detection of early-stage epithelial ovarian cancer in asymptomatic women who are at increased risk for disease.

Preoperative sonographic features of borderline ovarian tumors

OBJECTIVE

To determine the sonographic findings that distinguish borderline ovarian tumors (BOT) from both benign and invasive malignant tumors, thus allowing conservative treatment and laparoscopic management of these tumors.

METHODS

We reviewed retrospectively transvaginal sonograms of 33 women who, when evaluated further by surgery and histology, were found to have BOT. Twenty-three were premenopausal and 10 were postmenopausal (mean age +/- SD, 45.8 +/- 15.7 years). For each mass, size and morphological features and power Doppler characteristics were evaluated. We compared these findings with those of 337 patients with benign ovarian tumors and those of 82 patients with invasive malignant ovarian tumors. Patients with dermoid cysts were not included in the study.

RESULTS

Of the 33 BOT, 15 were mucinous and 18 were serous cystadenomas. The presence of papillae, defined as a small number of solid tissue projections, 1-15 mm in height and 1-10 mm in width (base) and length (base), into the cyst cavity from the cyst wall, was significantly more frequent in BOT (48%) than it was in benign (4%) and invasive (4%) malignant tumors. Intracystic solid tissue (> 15 mm in height or > 10 mm in width or length) was observed in 48% of invasive malignant masses but in only 18% of BOT and in 7% of benign tumors (P < 0.001). No sonographically unilocular, hypoechoic, smooth-walled adnexal cysts were invasively malignant but three unilocular cysts with a diameter of > 6 cm were serous BOT. Although close attention was paid to the cyst wall at ultrasound examination we did not observe in these three cysts the very small papillae which were found at histological analysis.

CONCLUSIONS

The most frequent diagnostic feature on imaging BOT is the presence of papillae within the cyst. However, neither papillae nor other sonographic features constituted highly sensitive sonographic markers of BOT.

Progress and challenges in screening for early detection of ovarian cancer

Ovarian cancer is characterize by few early symptoms, presentation at an advanced stage, and poor survival. As a result, it is the most frequent cause of death from gynecological cancer. During the last decade, a research effort has been directed toward improving outcomes for ovarian cancer by screening for preclinical, early stage disease using both imaging techniques and serum markers. Numerous biomarkers have shown potential in samples from clinically diagnosed ovarian cancer patients, but few have been thoroughly assessed in preclinical disease and screening. The most thoroughly investigated biomarker in ovarian cancer screening is CA125. Prospective studies have demonstrated that both CA125 and transvaginal ultrasound can detect a significant proportion of preclinical ovarian cancers, and refinements in interpretation of results have improved sensitivity and reduced the false-positive rate of screening. There is preliminary evidence that screening can improve survival, but the impact of screening on mortality from ovarian cancer is still unclear. Prospective studies of screening are in progress in both the general population and high-risk population, including the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), a randomized trial involving 200,000 postmenopausal women designed to document the impact of screening on mortality. Recent advances in technology for the study of the serum proteome offer exciting opportunities for the identification of novel biomarkers or patterns of markers that will have greater sensitivity and lead time for preclinical disease than CA125. Considerable interest and controversy has been generated by initial results utilizing surface-enhanced laser desorption/ionization (SELDI) in ovarian cancer. There are challenging issues related to the design of studies to evaluate SELDI and other proteomic technology, as well as the reproducibility, sensitivity, and specificity of this new technology. Large serum banks such as that assembled in UKCTOCS, which contain preclinical samples from patients who later developed ovarian cancer and other disorders, provide a unique resource for carefully designed studies of proteomic technology. There is a sound basis for optimism that further developments in serum proteomic analysis will provide powerful methods for screening in ovarian cancer and many other diseases.

Use of morphology to characterize and manage common adnexal masses

The use of grey-scale ultrasound morphology to characterize a pelvic mass may also be called 'pattern recognition'. The grey-scale ultrasound image provides us with the same information as that obtained by the surgeon or pathologist when he or she cuts a surgical specimen to see what it looks like inside. Many pelvic masses have such a typical macroscopic appearance that a fairly confident diagnosis can be made on the basis of their macroscopic appearance alone, i.e. on the basis of their grey-scale ultrasound image. This is true of most dermoid cysts, endometriomas, corpus luteum cysts, hydrosalpinges and peritoneal pseudocysts, and of many paraovarian cysts and benign solid ovarian tumours, for example, fibromas, fibrothecomas, thecofibromas, thecomas and Brenner tumours. A mass with irregularities should always evoke suspicion of malignancy. A mass that is completely smooth is almost certainly benign. Papillary projections--considered a strong sign of malignancy--are more common in borderline tumours than in invasive cancers but may also be seen in benign tumours, for example, in adenofibromas. They explain many false-positive ultrasound diagnoses of malignancy. Pattern recognition is superior to all other ultrasound methods (e.g. simple classification systems, scoring systems, mathematical models for calculating the risk of malignancy) for discrimination between benign and malignant extrauterine pelvic masses. Today's often too liberal use of transvaginal ultrasound gives clinicians problems. Many adnexal masses that probably would have remained undetected before the ultrasound era are now found incidentally at transvaginal ultrasound examination in women without symptoms of an adnexal tumour. The natural history of incidentally detected pelvic masses with benign ultrasound morphology is not known. Therefore, the optimal management of such tumours is also unknown.

The use of mathematical models to evaluate pelvic masses; can they beat an expert operator?

The pre-operative characterization of ovarian cysts remains a major challenge. Functional cysts and some other benign cysts should be managed conservatively, whereas persistent tumours may need removal. It is crucial to distinguish between malignant tumours, which are better treated by a gynaecological oncologist, and benign tumours, which may be suitable for minimal-access surgery. Over the past decade several ultrasound-based morphological scoring systems, colour Doppler parameters, logistic regression models and artificial neural networks have been proposed and tested in order to try to predict the histology of ovarian tumours. On prospective testing none of the current models can beat an expert sonologist. Signs of malignancy include the presence of papillary structures, irregular solid areas, septa and a strong vascularization at colour Doppler imaging. Further refinement of mathematical models and the results of multicentre trials need to be reviewed before the clinical use of mathematical models can be advocated.

The value of detection of normal ovarian tissue (the 'ovarian crescent sign') in the differential diagnosis of adnexal masses

OBJECTIVE

The aim of the study was to evaluate whether the presence of normal ovarian tissue adjacent to an adnexal tumor (the 'ovarian crescent sign') could assist in the preoperative differential diagnosis of adnexal lesions.

METHODS

This was a prospective observational study including 100 women with a preoperative diagnosis of an adnexal mass. Demographic and biochemical data were collected and all women underwent a detailed transvaginal ultrasound scan. Tumor volume, morphological characteristics and Doppler features were recorded in each case. In addition, the tissue adjacent to the cyst was systematically examined for the presence of normal ovarian tissue. All the findings were compared to the final histological diagnosis.

RESULTS

Sixty-seven (67%) of the cysts removed were benign, nine (9%) were borderline and 24 (24%) women had invasive malignant lesions. Normal ovarian tissue was seen in 58/76 (76%) women with non-invasive lesions, and in one woman (4%) with an invasive malignancy. In the absence of normal ovarian tissue, ovarian cancer was diagnosed with a sensitivity of 96% and specificity of 76%.

CONCLUSION

The presence of normal ovarian tissue adjacent to an ovarian cyst is a useful morphological feature that may be used to help exclude an invasive ovarian malignancy in women with adnexal masses detected on ultrasound scan.

Characterization of adnexal mass lesions on MR imaging

OBJECTIVE

The aim of our study was to evaluate the accuracy of MR imaging in the detection and characterization of adnexal mass lesions and to determine which imaging features are predictive of malignancy.

SUBJECTS AND METHODS

We prospectively performed MR imaging in 104 patients (age range, 19-87 years; mean age, 50 years) with clinically or sonographically detected complex adnexal masses. We used a 1.5-T unit to perform T1-, T2-, and fat-suppressed T1-weighted sequences before and after IV injection of gadolinium. The adnexal lesions were examined for several features including size, shape, character (solid-cystic), vegetation, signal intensity, and enhancement. Secondary signs such as ascites, peritoneal disease, and lymphadenopathy were noted. We compared the imaging features with the surgical and pathologic findings. Multiple logistic regression analysis was performed on all MR imaging features.

RESULTS

A total of 163 lesions--94 benign and 69 malignant lesions--were examined. On MR imaging, 95% (155/163) of the lesions were detected. The overall accuracy for the diagnosis of malignancy was 91%. On univariate analysis, the imaging features associated with malignancy were a solid-cystic lesion, irregularity, and vegetation on the wall and septum in a cystic lesion, the large size of the lesion, an early enhancement on dynamic contrast-enhanced MR images, and the presence of ascites, peritoneal disease, or adenopathy. On multiple logistic regression analysis, ascites and vegetation in a cystic lesion were the factors most significantly indicative of malignancy.

CONCLUSION

MR imaging is highly accurate in the characterization of adnexal mass lesions, and the best predictors of malignancy are vegetation in a cystic lesion and ascites.

A new scoring system to differentiate benign from malignant adnexal masses

OBJECTIVE

The purpose of this study was to develop and cross-validate a new sonographic scoring system for differentiation between benign and malignant adnexal masses.

STUDY DESIGN

This study was conducted in a tertiary care university hospital. In the first part of the study, we used a multivariate logistic regression analysis to develop a scoring system that was based on morphologic and Doppler sonographic data for 705 adnexal masses in 665 patients who were diagnosed and treated at our institution from January 1995 to June 2001. The scoring system was designed to use only those parameters that are found to be independent predictors of malignancy. In the second part of the study, we prospectively cross-validated this scoring system in a series of 90 adnexal masses in 86 patients between July 2001 and March 2002. With the use of the area under the curve of the respective ROC curves, we compared the new scoring system with other scoring systems.

RESULTS

Multivariate logistic regression analysis revealed that the only independent predictor parameters were thick papillary projections, solid areas, central flow, and velocimetric features of high velocity and low resistance. In the prospective cross-validation study, our scoring system had the best diagnostic performance (area under the curve, 0.98) compared with Sassone (area under the curve, 0.89; P =.017), De Priest (area under the curve, 0.92; P =.048), and Ferrazzi (area under the curve, 0.90; P =.013) scoring systems.

CONCLUSION

Our new sonographic scoring system had a better diagnostic performance than three previously published scoring systems.

Prognostic significance of ultrasound derived intratumoral peak systolic velocity in epithelial ovarian cancer

OBJECTIVE

To evaluate the prognostic significance of ultrasound derived intratumoral peak systolic velocity in epithelial ovarian cancer.

DESIGN

Color Doppler imaging and pulsed Doppler spectral analysis were used in the investigation of 49 patients with epithelial ovarian cancer (19 serous, 15 mucinous, eight endometrioid, four clear cell and three Brenner cell) immediately before laparotomy. Twenty-two were stage I, six were stage II, 17 were stage III and four were stage IV. Sections of malignant tumors were analyzed for the cellular expression of thymidine phosphorylase and the intratumoral density of microvessels by immunohistochemistry using antibodies to thymidine phosphorylase and factor VIII-related antigen, respectively. Moreover, the apoptotic index was evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling method. Intratumoral peak systolic velocity was tested for correlation with patients' age at diagnosis, stage of disease, presence of a residual tumor, histological subtype and grade, thymidine phosphorylase expression, apoptotic index, microvessel count and patient survival.

RESULTS

Histological grade (P = 0.025), thymidine phosphorylase expression (P = 0.044), apoptotic index (P = 0.039) and microvessel count (P = 0.014) were all significantly associated with peak systolic velocity. Stage of disease (P = 0.002), presence of residual disease (P = 0.0002) and peak systolic velocity (P = 0.041) were found by univariate Cox regression analysis to be significantly associated with a poor prognosis. Multivariate Cox regression analysis revealed that stage of disease (P = 0.006) and peak systolic velocity (P = 0.008) are independent prognostic factors.

CONCLUSIONS

Intratumoral peak systolic velocity could be a preoperatively pertinent prognostic predictor of survival in patients with epithelial ovarian cancer.