A multivariate logistic regression analysis in predicting malignancy for patients with ovarian tumors

Risk of malignancy in unilocular cysts: a study of 1148 adnexal masses classified as unilocular cysts at transvaginal ultrasound and review of the literature

OBJECTIVES

The aim of this study was to estimate the rate of malignancy in adnexal lesions described as unilocular cysts at transvaginal ultrasound examination and to investigate if there are differences in clinical and ultrasound characteristics between benign and malignant unilocular cysts.

METHODS

A total of 3511 patients with an adnexal mass underwent transvaginal ultrasound examination between 1999 and 2007. Sonologists used the International Ovarian Tumor Analysis terms and definitions to describe their ultrasound findings. Only masses operated on within 120  days after the ultrasound examination were included in the analysis and the histopathological diagnosis of the mass was used as the gold standard.

RESULTS

Of the 3511 masses, 1148 (33%) were classified as unilocular cysts on ultrasound. Of these, 11 (0.96% (95% CI, 0.48-1.71)) were malignant. The malignancy rate was lower in premenopausal than in postmenopausal women: 0.54% (5/931; 95% CI, 0.17-1.25) vs. 2.76% (6/217; 95% CI, 1.02-5.92); P = 0.009. More patients with malignant unilocular cysts had a personal history of breast cancer (18% vs. 2%; P = 0.02) or ovarian cancer (18% vs 0.6%; P = 0.003). Hemorrhagic cyst contents on ultrasound were more common in malignant than in benign unilocular cysts (18% vs. 2%; P = 0.03). In seven of the 11 malignancies judged to be unilocular cysts at scan, papillary projections or other solid components were seen at macroscopic inspection of the surgical specimen.

CONCLUSIONS

The malignancy rate in surgically removed adnexal lesions judged to be unilocular cysts at transvaginal scan is c 1%. Postmenopausal status, personal history of breast or ovarian cancer and hemorrhagic cyst contents on ultrasound increase the risk of malignancy. To avoid misclassifying adnexal lesions as unilocular cysts at scan, it is important to scrutinize unilocular cysts for the presence of solid components.

Smoking influences aberrant CpG hypermethylation of multiple genes in human prostate carcinoma

BACKGROUND

Aberrant CpG methylation profiles of gene promoters and their correlation with advanced pathologic features have been well investigated in prostate carcinoma (PC). Several case-control and prospective studies have revealed a positive association between current smoking and PC. The authors hypothesized that smoking influences both progression and prognosis of PC through CpG hypermethylation of related genes.

METHODS

A total of 164 PC patients (52 current, 30 former, and 82 never smokers) and 69 benign prostatic hyperplasia (BPH) patients were examined by methylation-specific PCR (MSP) for 3 genes: adenomatous polyposis coli (APC), glutathione S-transferase pi (GSTP1), and multidrug resistance one (MDR1). The methylation status of representative samples was confirmed by bisulfite DNA sequencing analysis. The newly defined methylation score (M-score) of each sample is the sum of the corresponding log hazard ratio (HR) coefficients derived from multivariate logistic regression analysis for pathology (BPH vs. PC), and was related to clinical and pathologic outcome including smoking status.

RESULTS

The M-score was significantly higher in the current smokers than in never smokers (P = 0.008). Spearman rank correlation test demonstrated a significant correlation between pack-years smoked and M-score in PCs (P = 0.039). Significant correlation of the M-score methylation was observed with high pT category (P < 0.001), high Gleason sum (P < 0.001), high preoperative prostate-specific antigen (PSA) (P = 0.041), and advanced pathologic features. In addition, Gleason sum was significantly associated with PSA failure-free probability as a poor outcome (P = 0.020).

CONCLUSIONS

This is the first study to demonstrate significant correlation of the methylation status of multigenes with smoking status in PC. Smoking status may influence both progression and prognosis of PC through CpG hypermethylation of related genes.

Prediction of minor head injured patients using logistic regression and MLP neural network

In this study it is aimed to assess the posttraumatic cerebral hemodynamia in minor head injured patients. Eighty patients with minor head injury (Group 1) evaluated in the early 8 h of posttraumatic period between July 2003 and February 2004. The control group (Group 2) has composed of 32 healthy people. Bilateral blood flow velocities of middle cerebral arteries (MCA) had measured using transtemporal technique while internal carotid arteries were evaluated by submandibular examination. Two different mathematical models such as the traditional statistical method on the basis of logistic regression and a multi-layer perceptron (MLP) neural network are used to classify the age, sex, velocitiy parameters of MCA, mean velocity of extracranial ICAs and V(MCA)/ V(ICA) ratios. The neural network was trained, cross-validated and tested with subject's transcranial Doppler signals. As a result of these classifications, we found the success rate of logistic regression, the success rate of MLP neural network is 88.2 and 89.1%, respectively. The classification results show that MLP neural network is offering the best results in the case of diagnosis.

Multigene Methylation Analysis for Detection and Staging of Prostate Cancer

PURPOSE

Aberrant gene promoter methylation profiles have been well-studied in human prostate cancer. Therefore, we rationalize that multigene methylation analysis could be useful as a diagnostic biomarker. We hypothesize that a new method of multigene methylation analysis could be a good diagnostic and staging biomarker for prostate cancer.

EXPERIMENTAL DESIGN

To test our hypothesis, prostate cancer samples (170) and benign prostatic hyperplasia samples (69) were examined by methylation-specific PCR for three genes: adenomatous polyposis coli (APC), glutathione S-transferase pi (GSTP1), and multidrug resistance 1 (MDR1). The methylation status of representative samples was confirmed by bisulfite DNA sequencing analysis. We further investigated whether methylation score (M score) can be used as a diagnostic and staging biomarker for prostate cancer. The M score of each sample was calculated as the sum of the corresponding log hazard ratio coefficients derived from multivariate logistic regression analysis of methylation status of various genes for benign prostatic hyperplasia and prostate cancer. The optimal sensitivity and specificity of the M score for diagnosis and for staging of prostate cancer was determined by receiver-operator characteristic (ROC) curve analysis. A pairwise comparison was employed to test for significance using the area under the ROC curve analysis. For each clinicopathologic finding, the association with prostate-specific antigen (PSA) failure-free probability was determined using Kaplan-Meier curves and a log-rank test was used to determine significance. The relationship between M score and clinicopathologic findings was analyzed by either the Mann-Whitney U test, Kruskal-Wallis test, or the Spearman rank correlation test.

RESULTS

The frequency of positive methylation-specific PCR bands for APC, GSTP1, and MDR1 genes in prostate cancer samples was 64.1%, 54.0%, and 55.3%, respectively. In benign prostatic hyperplasia samples, it was 8.7%, 5.8%, and 11.6%, respectively. There was a significant correlation of M score with high pT category (P < 0.001), high Gleason sum (P < 0.001), high preoperative PSA (P = 0.027), and advanced pathologic features. For all patients, the M score had a sensitivity of 75.9% and a specificity of 84.1% as a diagnostic biomarker using a cutoff value of 1.0. In patients with low or borderline PSA levels (<10.0 ng/mL), the M score was significantly higher in prostate cancers than in benign prostatic hyperplasias (2.635 +/- 0.200 and 0.357 +/- 0.121, respectively). ROC curve analysis revealed that the M score had a sensitivity of 65.4% and a specificity of 94.2% when 1.0 was used as a cutoff value. For all patients, M score can distinguish organ-confined (< or =pT(2)) from locally advanced cancer (> or =pT(3)) with a sensitivity of 72.1% and a specificity of 67.8%. Moreover, considering patients with PSA levels of <10 ng/mL, the M score has a sensitivity of 67.1% and a specificity of 85.7%. The ROC curve analysis showed a significant difference between M score and PSA (P = 0.010).

CONCLUSIONS

This is the first report demonstrating that M score is a new method for multigene methylation analysis that can serve as a good diagnostic and staging biomarker for prostate cancer.

Classification of carotid artery stenosis of patients with diabetes by neural network and logistic regression

The blood flow hemodynamics of carotid arteries were obtained from carotid arteries of 168 individuals with diabetes using the 7.5 MHz ultrasound Doppler M-unit. Fast Fourier Transform (FFT) methods were used for feature extraction from the Doppler signals on the time-frequency domain. The parameters, obtained from the Doppler sonograms, were applied to the mathematical models that were constituted to analyze the effect of diabetes on internal carotid artery (ICA) stenosis. In this study, two different mathematical models such as the traditional statistical method based on logistic regression and a Multi-Layer Perceptron (MLP) neural network were used to classify the Doppler parameters. The correct classification of these data was performed by an expert radiologist using angiograpy before they were executed by logistic regression and MLP neural networks. We classified the carotid artery stenosis into two categories such as non-stenosis and stenosis and we achieved similar results (correctly classified (CC) = 92.8%) in both mathematical models. But, as the degree of stenosis had been increased to 4 (0-39%, 40-59%, 60-79% and 80-99% diameter stenosis), it was found that the neural network (CC = 73.9%) became more efficient than the logistic regression analysis (CC = 67.7%). These outcomes indicate that the Doppler sonograms taken from the carotid arteries may be classified successfully by neural network.

Color Doppler energy prediction of malignancy in adnexal masses using logistic regression models

OBJECTIVE

The aim of this study was to assess the usefulness of color Doppler energy in the preoperative diagnosis of ovarian malignancy using multivariate logistic regression analysis.

METHODS

One hundred and thirty adnexal masses were studied with transvaginal B-mode, color energy, and pulsed Doppler ultrasonography before surgery in order to develop a model that could be used to determine malignancy. Each ultrasonographic variable (tumor size, wall thickness, septal structure, echogenicity, papillary projection, density (solid or not)) was included individually or combined together as part of the Sassone ultrasound score. Intratumoral blood flow velocity waveforms were obtained to determine pulsatility index and resistance index and a more subjective parameter, location of tumor vascularity, was also assessed. Menopausal status and serum CA 125 levels were also entered as categorical variables. Sonographic parameters were entered alone, then associated with menopausal status and CA 125 serum levels, and finally with Doppler energy measurements. Our model was then validated in a group of 68 adnexal masses and compared to the model of Alcazar.

RESULTS

Eighteen adnexal masses (13.8%) were malignant or of low malignant potential. Multivariate analysis showed that papillary projection of the tumor wall, cyst with solid parts, resistance index with a cut-off value of 0.53, CA 125, and central blood flow location, were the only factors to be independent predictors of malignancy. Menopausal status was not an independent factor. For the final model including the Doppler energy parameter the best sensitivity and specificity were 83% and 93%, respectively, at a cut-off value of 10% probability of malignancy compared to 83% and 87% for the morphological variables alone. Validation of the model showed its diagnostic performance to be as good as that reported in the original population and better than the model of Alcazar.

CONCLUSION

Sonographic analysis of adnexal masses including color Doppler energy shows the best predictive properties according to histological diagnosis, and improves preoperative diagnosis of malignancy.

The differential diagnostic potential of a panel of tumor markers (CA 125, CA 15-3, and CA 72-4 antigens) in patients with a pelvic mass

OBJECTIVE

The purpose of this study was to assess the differential diagnostic potential of a combination of CA 125, CA 15-3, and CA 72-4 antigens in the definition of malignant disease, especially ovarian carcinoma in patients with a pelvic mass.

STUDY DESIGN

A total of 412 patients were evaluated in a multicenter, retrospective study.

RESULTS

Two hundred twenty-six malignant, 171 benign pelvic tumors (of which 129 were benign ovarian tumors), and 15 borderline tumors were evaluated. One hundred thirty-three patients had ovarian carcinoma. In 76 cases (55%), the International Federation of Gynecology and Obstetrics stage was III or IV. Borderline tumors (n = 15) were excluded from the statistical calculations. CA 125 antigen was the most sensitive marker for ovarian carcinoma (81%). The highest specificity and positive predictive value was obtained with CA 15-3 antigen (95% and 92%, respectively). Considering a concomitant elevation of all 3 markers as positive, a positive predictive value of 97% was found. However, only 28% of the patients in the total group and 41% of the patients with ovarian carcinoma had a concomitant elevation of all 3 markers. The combination of all 3 markers with levels below the cut-off resulted in a (false-positive) positive predictive value for malignancy between 12% and 36%. With the use of logistic regression analysis, we found a correct prediction in 73% of the cases. CA 15-3 antigen makes the most significant (P <.0001) contribution to the logistic model in the prediction of malignancy in the total group, with all pelvic masses with an odds ratio of 3.86.

CONCLUSION

The combination of a simultaneous elevated level of CA 125, CA 15-3, and CA 72-4 antigens was predictive for malignant disease in almost all cases. However, such concomitant elevation was found in few of the malignant masses. Logistic regression analysis revealed that CA 15-3 antigen makes the most significant contribution to a model for the prediction of malignancy in the total group. The logistic model gave a correct prediction in 73% to 83%. The present tumor marker panel seems inferior to combinations with other test modalities, which include ultrasonography and/or physical examination and/or menopausal status or age.

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.

Combined transvaginal B-mode and color Doppler sonography for differential diagnosis of ovarian tumors: results of a multivariate logistic regression analysis

OBJECTIVE

Transvaginal sonography is limited in its ability to assess early stage cancers of the ovary as well as in distinguishing benign processes. As a method for characterization of tumor vascularization, color-coded Doppler sonography may be able to improve the diagnostic accuracy of B-mode sonography.

METHODS

Preoperative transvaginal B-mode and Doppler sonography was performed in 63 patients with unclear adnexal lesions prior to operation. Using multiple logistic regression, the independent variables of each procedure were selected and combined to yield a diagnostic flow chart. The diagnostic accuracy of this decision matrix was tested on 257 patients with unclear adnexal tumors.

RESULTS

In the 63 adnexal tumors investigated, the diagnostic impact of isolated sonomorphological assessment with evidence of a "solid area" was 78%. Using Doppler sonography, the best discrimination was achieved by displaying the vascular distribution ("central vascularization"). Combining these independent significant variables of the two procedures raised the diagnostic accuracy to 90% (sensitivity 86%, specificity 93%). The validity achieved by this combination was confirmed by the independent application of this method to the 257 adnexal tumors with unclear malignancy status (diagnostic accuracy 93%, sensitivity 92%, specificity 94%).

CONCLUSIONS

The combination of sonography and Doppler sonography achieves high and reproducible diagnostic accuracy in preoperative malignancy status assessment of adnexal tumors. The additional use of Doppler sonography can thus provide significant aid both for differential diagnostics of adnexal lesions and for the choice of surgical route in the case of an existing indication for operative therapy.

Gynaecological presentation of retroperitoneal tumours

OBJECTIVE

To illustrate the problems associated with mistaken pre-operative diagnosis following gynaecological presentation of patients with retroperitoneal tumours.

DESIGN

A case series of five referrals.

RESULTS

Non-gynaecological tumours were not suspected in each case and hence there was a failure to undertake further pre-operative investigation and referral to a specialised soft tissue sarcoma service. This resulted in four of the patients having an unnecessary laparotomy with an inappropriate transperitoneal biopsy undertaken when the retroperitoneal tumour was discovered. The mistaken diagnosis of ovarian malignancy lead to increased morbidity, compromise of potential for a long disease free interval and/or possibly lessened the chance of cure in each case.

CONCLUSIONS

Misinterpretation of clinical signs and an over-reliance on ultrasound diagnosis were the commonest causes of inappropriate management of these patients. Gynaecologists should consider more frequently the other, less common differential diagnoses of a pelvic mass. This is especially true in circumstances with a predominantly solid tumour, where there are clinical signs of vascular or rectal displacement, or where there is ultrasound evidence of ureteric obstruction. The more frequent utilisation of a computerised tomography scan with intravenous and oral contrast with referral before inappropriate transperitoneal biopsy are recommended as complete en bloc surgical excision at the first laparotomy is the treatment of choice in virtually all primary retroperitoneal tumours.