Effects of PTK787/ZK 222584, a specific inhibitor of vascular endothelial growth factor receptor tyrosine kinases, on primary tumor, metastasis, vessel density, and blood flow in a murine renal cell carcinoma model

Antiangiogenic therapy is a promising new strategy to inhibit tumor growth and formation of metastases. Vascular endothelial growth factor (VEGF) and its receptors, VEGF-receptor 1 (VEGF-R1; FLT-1) and VEGF-R2 (KDR), have been shown to play a major role in tumor angiogenesis. PTK787/ZK 222584, a specific inhibitor of both VEGF-receptor tyrosine kinases, was investigated for its antitumoral and antiangiogenic activity in a murine renal cell carcinoma model. After intrarenal application of the renal carcinoma cells, mice develop a primary tumor and metastases to the lung and to the abdominal lymph nodes. Daily oral therapy with PTK787/ZK 222584 at a dose of 50 mg/kg resulted in a significant decrease of 61 and 67% in primary tumors after 14 and 21 days, respectively. The occurrence of lung metastases was significantly inhibited at both time points (98% reduction and 78% reduction, respectively). After 14 days, no lymph node metastases developed in the PTK787/ZK 222584-treated group, whereas after 21 days of treatment, the lymph node metastases were reduced by 87%. Vessel density in tumor tissues, detected by immunohistochemistry with an anti-CD31 antibody, was significantly decreased by PTK787/ZK 222584. Using color Doppler imaging ultrasound, significant changes in blood flow in the tumor feeding renal artery were found under treatment with PTK787/ZK 222584. Blood flow changes correlated with changes in vessel density but not with tumor volume. The compound was well tolerated in all in vivo experiments and had no significant effects on body weight or general well-being of the animals. This was in contrast to the animals treated with the antiangiogenic agent TNP-470. s.c. therapy with 30 mg/kg TNP-470 every other day had to be discontinued after 13 days because of animal weight loss (>20%) and ataxia. These results demonstrate that PTK787/ZK 222584 is a potent inhibitor of tumor growth, metastases formation, and tumor vascularization in murine renal cell carcinoma. Furthermore, we have been able to demonstrate that color Doppler imaging ultrasound can be used to measure blood flow to a tumor and that flow correlates with vessel density. Thus, this may be a valuable noninvasive method for monitoring the effects of antiangiogenic agents such as PTK787/ZK 222584 on tumor vasculature.

Sonography of palpable breast cancer

PURPOSE

Because of the increasing use of sonography to rule out cancer in women with palpable breast abnormalities, this study was performed to determine the rate of sonographically occult malignancy in this clinical setting.

METHODS

Women who were recommended for biopsy based on mammographic and/or clinical findings underwent breast sonography. This study retrospectively analyzed the subset of patients with palpable malignant lesions. Lesions were classified as visible or occult on mammography and sonography. Patients without a tissue diagnosis of tumor were excluded.

RESULTS

Of 1,346 masses that underwent biopsy or aspiration, 616 lesions were palpable, and of these, 293 were malignant. Sonography detected all 293 palpable malignant lesions (95% confidence interval for sensitivity, 99-100%). Eighteen lesions were mammographically occult. The median lesion size as determined by sonography was 1.8 cm; for the lesions that were mammographically occult, the median size was 1.6 cm. The most common histopathologic diagnosis for both groups of lesions was infiltrating ductal carcinoma.

CONCLUSIONS

All palpable malignant breast lesions were visible by sonography in patients in whom a biopsy was recommended. However, we caution that until the false-negative rate of sonography for equivocal palpable abnormalities is determined prospectively, sonography cannot be accurately applied to rule out malignancy in this setting.

Ultrasound demonstration of mammographically detected microcalcifications

PURPOSE

To evaluate the capabilities of breast ultrasound (US) for identifying microcalcifications in benign breast changes, in situ carcinomas, and small nonpalpable invasive carcinomas.

MATERIAL AND METHODS

Forty-six consecutive patients with 49 clustered microcalcifications detected by mammography were included in this prospective study. Patients with palpable breast lesions were excluded. Breast US was performed with knowledge of mammographic findings for presence and visibility of microcalcifications, and for parenchymal structure abnormalities. Mammographic and US findings were compared with histology.

RESULTS

Nine ductal in situ carcinomas, 2 lobular in situ carcinomas, 11 invasive carcinomas and 27 benign lesions were confirmed by histology. For all lesions, US achieved a sensitivity of 75% in the detection of microcalcifications. The detection rate for microcalcification in invasive and in situ carcinomas was 100%. In 11 cases, no microcalcifications were visible on US; they all proved to be benign on histology.

CONCLUSION

Microcalcifications in malignant lesions are reliably recognized by US. They are, however, difficult to detect in fibrocystic breast changes.

The role of enhanced Doppler ultrasound in differentiation of benign vs. malignant scar lesion after breast surgery for malignancy

AIM

To evaluate the benefit of echo-contrast-enhanced Doppler sonography in the differentiation of benign vs. malignant breast lesions after surgical removal of a malignant breast mass.

METHODS

Thirty-eight patients referred for biopsy of a palpable, suspicious scar lesion 1-15 years (mean 3.3 years) after surgery for breast cancer were examined. During baseline ultrasound examination a subjective scoring system of the vascularity, the number, the regularity of vessels' course and their Doppler parameters were assessed. After injection of an ultrasound contrast agent (Levovist) the same scoring system was applied to the parameters together with enhancement kinetics, enhancement intensity and enhancement pattern. Any increase in the scoring level of two or more characteristics (vascularity, number of vessels, intensity of enhancement in the tumor or regularity score of vessels in the lesion) was defined as suspicious for malignancy. A marked increase of enhancement in the immediate tumor periphery was also regarded as suspicious for malignancy. The sonographic results were assessed prospectively and correlated with the histology of the lesion.

RESULTS

Of the 38 patients with a clinically-suspicious scar lesion, there were 28 true scars and 10 malignant scar lesions. All scar lesions showed no or slight vascularity on baseline sonography. After Echocontrast-enhancement a significant increase in tumor vascularity and the number of tumor vessels could be demonstrated in all 10 malignant lesions but in only one of the 28 benign scars.

CONCLUSION

Scars pose inherent technical problems for optimal mammography. Sonographic evaluation of the vascularity of the lesion with contrast enhancing agents showed improved diagnostic accuracy in the hands of an experienced examiner.

Contrast-enhanced colour Doppler ultrasonography in suspected breast cancer recurrence

BACKGROUND

Postoperative scarring and radiotherapy changes in the conservatively treated breast often mimic breast cancer recurrence, resulting in many unnecessary biopsies. Local breast cancer recurrence may be detected more accurately with contrast-enhanced colour Doppler imaging.

METHODS

Fifty-eight women with suspected local breast cancer recurrence were evaluated prospectively by means of conventional and contrast-enhanced colour Doppler imaging before surgical biopsy.

RESULTS

Sensitivity for the detection of breast cancer recurrence using contrast enhancement was 94 per cent (specificity 67 per cent). Contrast enhancement significantly increased overall diagnostic accuracy, from 80 to 90 per cent (P < 0. 04).

CONCLUSION

Contrast-enhanced colour Doppler imaging is a highly accurate method for detecting local breast cancer recurrence. Its adoption may substantially reduce biopsy rates.

Differentiation of benign and malignant breast tumors by logistic regression and a classification tree using Doppler flow signals

In breast examinations with Doppler, an increased flow is found in malignant tumors. With the relatively new color Doppler, we measured different flow values in 133 cancer patients and in 325 women with benign disease. These measurements were used to develop diagnostic rules. For the highly correlated flow values, we used a stepwise procedure to select a final logistic regression model and a tree-based approach, which is a different way of modeling. With both approaches we developed simple diagnostic rules of which the sensitivity and the specificity exceeded 90%. There are no differences between the two approaches concerning discriminative ability. As complex statistical modeling leads to an overoptimism in the assessment of the error rates, we applied sensitivity analysis, investigated the stability of the selected logistic regression model, and estimated the magnitude of the overoptimism of the diagnostic rules with resampling methods. The results indicate that the estimates of sensitivity and specificity are probably close to realistic values for a clinical setting.

Color Doppler and duplex flow analysis for classification of breast lesions

The purpose of this study was to evaluate the differences of blood supply in benign and malignant breast tumors by color Doppler flow measurements. The study included 471 patients, 133 with carcinomas, 325 with benign breast lesions, and 13 with mastitis. An ATL UM9/HDI was used with an electronic 10-MHz linear array broadband transducer. The following flow data were analyzed: Presence of vascularity; number of tumor arteries; the mean, minimum, maximum RI index, and AB ratio; the mean, minimum, and maximum peak systolic flow velocity and the sum of all peak systolic flow velocities in each tumor. In all cancers and in most benign pathologies vascularity was found. Highly significant differences between benign and malignant were found for all quantitative flow data such as number of tumor arteries and blood flow velocity (P < 0.0001). Flow profiles analyzed by RI index and AB ratio showed a trend for increased flow resistance in malignancies. However, due to the wide overlap between benign and malignant, indices did not allow a sufficient differentiation. The study showed that standardization of the Doppler examination technique and equipment parameters is essential for vascularity assessment of tumors.

Diagnostic formula for the differentiation of adnexal tumors by transvaginal sonography

OBJECTIVE

To create a strategy for sonographic differentiation of benign and malignant adnexal tumors in premenopausal and postmenopausal patients.

METHODS

Multiple sonomorphologic criteria were analyzed prospectively in 754 tumors. Four hundred were found in premenopausal and 354 in postmenopausal women. In a logistic regression model, relevant criteria were selected, and a diagnostic formula for tumor differentiation was derived.

RESULTS

There were 165 malignant tumors, of which 37 (9.2%) were found in premenopausal and 128 (36.2%) in postmenopausal women. In both groups, the criteria of solid phase and ascites were the most significant. Further important diagnostic criteria were structure and tumor size in premenopausal women and cyst architecture and tumor surface in postmenopausal women. These results allowed an estimation of the probability of malignancy. Using a cutoff point of 10% for the probability to classify tumors as malignant, the sensitivity and specificity in premenopausal patients were 86.5% and 92.6%, respectively, with an accuracy of 92%. In postmenopausal women, the sensitivity, specificity, and accuracy were 93%, 82.7%, and 86.6%, respectively. Assuming a prevalence as given in the study, the positive and negative predictive values were 54.4% and 98.5% in premenopausal and 75.3% and 95.4% in postmenopausal women.

CONCLUSIONS

With four binary criteria, a useful diagnostic formula for tumor differentiation was obtained. However, estimates for sensitivity, specificity, and accuracy may be too optimistic because they were derived from the same data that were already used for model selection.

Multiple giant fibroadenomas: clinical presentation and radiologic findings

We describe the case of a 25-year-old Caucasian woman suffering from unilateral enlargement of the breast. Morphologic evaluation of various imaging modalities including mammography, ultrasound, and magnetic resonance imaging suggested a benign tumor embedded in stromal tissue. The time course of the Gd-DTPA uptake in dynamic magnetic resonance imaging, however, was also compatible with a malignant lesion. Postoperative pathological examination revealed multiple giant fibroadenomas, a rare disease, usually encountered in black female adolescents. Radiologic presentation, differential diagnosis, and morphologic findings are discussed, and a review of the literature is contained herein.

[Combined evaluation of ovarian tumors with transvaginal B-image and color Doppler ultrasound]

Transvaginal sonomorphologie and colour Doppler measurements were obtained preoperatively in 212 adnexal tumours: 81 premenopausal tumours (13 malignant and 68 benign) and 131 postmenopausal tumours (55 vs 76). Tumours were divided into five different scores according to their sonomorphology [16]. Scores I and II are related to benign tumours. Score V represents typically malignant tumours. Scores III and IV are associated with benign and malignant tumours. If score I and II are considered as benign and score III to V as malignant the sensitivity in pre- and postmenopausal tumours is 90%. However, the specificity is only 56% vs 70% respectively. In order to improve the accuracy, colour Doppler was additionally performed in tumours with sonomorphological score III and IV. The following criteria were tested: minimum resistance index (Rlmin), number of tumour arteries (ART), maximum (Smax) and sum (Ssum) of peak systolic velocities. All criteria showed significant differences between benign and malignant tumours. Tumours of score III and IV were differentiated by colour Doppler with an accuracy between 66% and 81% for premenopausal and 69% to 86% for postmenopausal women. The combination of sonomorphology and colour Doppler increased the accuracy between 84% and 90% with a sensitivity of up to 92% in pre- and 89% in postmenopausal patients. Sequential colour Doppler sonography as a supplement to transvaginal sonography improves tumour differentiation. The limitation of colour Doppler measurements to score III and IV lesions reduced the length of examination time to a reasonable extent.

Classification of adnexal tumors by transvaginal color Doppler

The purpose was to evaluate the validity of transvaginal color Doppler sonography for differentiating between benign and malignant ovarian tumors. Color Doppler and Duplex measurements were obtained in 212 (144 benign, 68 malignant) ovarian and tubarian tumors preoperatively. One hundred and thirty-one patients were postmenopausal and 81 premenopausal. An ATL UM9/HDI was used. The following criteria were analyzed: minimum and mean resistance index and pulsatility index, number and distribution of tumor arteries, diastolic notch, and the maximum, minimum, mean, and sum of all peak systolic, maximum enddiastolic, and time-average maximum velocities. Most criteria showed highly significant differences between benign and malignant tumors with variable overlaps. RImin gives a sensitivity of 80%, specificity of 69%, and accuracy of 75% for postmenopausal patients and 80, 59, and 67% for pre- and postmenopausal patients, respectively. PImin gives equivalent results. The number of tumor arteries and the maximum flow velocities increase the accuracy. The summation of all flow velocities gives the best result with a sensitivity of 93%, specificity of 85%, and accuracy of 87% for postmenopausal and 91, 76, and 80% for pre- and postmenopausal tumors, respectively. Flow data show no relevant differences between low malignant potential tumors and ovarian carcinomas. Serous cystadenomas and benign teratomas show higher differences than mucinous cystadenomas, functional cysts, and endometriomas in comparison to malignancies. A separate analysis of pre- and postmenopausal tumors is important. Differentiation seemed better for post- than for premenopausal tumors. The four flow criteria (RImin, number of tumor arteries, and maximum and sum of all peak systolic velocities) seemed appropriate for tumor differentiation. However, this study confirms that a single measurement is not sufficient to differentiate ovarian lesions. Measurements of flow velocities (e.g., maximum and sum of all peak systolic velocities) are superior compared with RImin and PImin.

[Phantom studies of ultrasound equipment for quality improvement in breast diagnosis]

AIM

According to the German guidelines for quality control of ultrasonic equipment, the following conditions are required for breast ultrasound: A transducer frequency between 5-7.5 MHz and a minimum field of view of 5 cm. Satisfactory images must be obtained in a depth between 0.5 and 4 cm with a wide tolerance of the focal zones. This allows the use of poor quality equipment which does not produce satisfactory image quality and it excludes a number of high frequency and high resolution transducers with a field of view below 5 cm. This study with a test phantom was performed to define image quality objectively.

METHOD

Sixteen ultrasound instruments in different price categories were used to perform standardized examinations on a breast phantom model 550 (ATS Laboratories, Bridgeport, USA). Contrast and spatial resolution in different penetration depths were investigated on cyst phantoms from 1-4 mm diameter and wire targets with defined distances between 0.5-3 mm 4 investigations reported the images.

RESULTS

A positive correlation was seen between price category and image quality.

CONCLUSION

This study demonstrates that transducer frequency and image geometry do not allow sufficient quality control. An improvement of ultrasound diagnosis is only possible if equipment guidelines are based on standard examinations with test phantoms.

[Ultrasound and mammography follow-up of findings after breast saving operation and adjuvant irradiation]

AIM

The aim of our controlled retrospective study was to assess the diagnostic value of sonography for detection and characterisation of changes compared to mammography and palpation.

METHOD

In 80 patients sonographic and clinical follow-up examinations were performed every 3 to 6 months, mammography examinations were performed every 6 to 12 months during the first 2 years after breast-preserving therapy (BPT) and irradiation. Extension, echogenicity, and configuration of lesions in sonography, and semiquantitiative description of diffuse or circumscribed changes in mammography were the basis of comparative follow-up observation.

RESULTS

Postoperative seromas and haematomas, initially presenting echo-free or as hypoechoic lesions, showed an increase in echogenicity within 18 months after irradiation. Fat necrosis occurred in 9.5% of patients, lymph cysts developed in 4%, granuloma in 3%, recurrence of neoplasma in 1.6%. The diffuse loss of transparency in mammography that was associated with radiation therapy, showed a peak 6-12 months after irradiation.

CONCLUSION

Sonography and sonographic guided puncture are mandatory tools to characterise circumscribed unclear lesions after breast-conserving therapy and irradiation in specialised centers. We recommend a 6-month interval for combined sonography, palpation, and mammography within the first 2 years after BPT and irradiation, because shorter control intervals did not result in relevant diagnostic advantages.

Differential diagnosis of breast lesions by color Doppler

Color Doppler allows flow detection in small tumor vessels. Due to the vascularity associated with the growth of malignancies, this method can be used to differentiate between benign and malignant breast lesions. In order to study the typical flow characteristics, we investigated multiple Doppler flow parameters. A UM9 HDI (ATL) was used with a linear transducer L 10-5. The number of tumor vessels and the mean, maximum and total flow velocity were measured in 325 benign and 133 malignant lesions and showed highly significant differences (p < 0.0001). Flow profiles (resistance index and systolic/diastolic frequency ratio) showed a large overlap and did not allow accurate tumor differentiation when mean and minimum values were analyzed. Surprisingly, the maximum resistance index and systolic/diastolic frequency ratio were significantly higher in carcinomas than in benign lesions, but the overlap of the values was wider than the flow velocity measurements. Using the vessel number and the total tumor vascularity, 90% of all lesions could be differentiated. A difficulty that we encountered was that a few cancers have very low flow values and some of the proliferative benign lesions can have increased flow.

Co-cultivation of ovarian carcinoma cells with dermal fibroblasts induces fibroblast expression of sex steroid receptor transcripts and protein

We have previously reported that stromal fibroblasts of ovarian carcinoma specimens may express estrogen (ER) and progesterone receptors (PR) when the malignant epithelial cells do not, and even when the specimens have been obtained from such non-Müllerian structures as the omentum whose fibroblasts normally express neither ER nor PR. In an attempt to investigate whether our observations of the expression of ER and PR in fibroblasts surrounding metastatic invasive epithelial ovarian carcinoma cells might result from an interaction involving malignant epithelial cells and stromal fibroblasts, we co-cultivated in vitro BG1 ovarian carcinoma cells with sex steroid receptor-negative dermal fibroblasts to determine whether carcinoma cells might induce the latter to express ER or PR protein and transcripts at levels detectable by standard immunocytochemical (ICC) and in situ hybridization (ISH) techniques. We report the in vitro induction of ER and PR transcripts and protein in previously steroid receptor-negative skin fibroblasts after co-cultivation with BG1 ovarian adenocarcinoma cells. Such observations suggest that a juxtacrine mechanism is responsible for the observed phenomenon, possibly involving ER- and PR-inducing factors (ER-IF and PR-IF).

Quantitative flow measurements for classification of ovarian tumors by transvaginal color Doppler sonography in postmenopausal patients

Color Doppler and Duplex measurements were obtained in 83 (42 benign, 41 malignant) ovarian tumors in postmenopausal patients. An ATL UM9/HDI was used. The following flow criteria were analyzed: lowest resistance index (RI) and pulsatility index (PI), total number of arteries and number of central arteries and the maximum, mean and sum of systolic, end-diastolic and time-averaged maximum velocities of all intratumoral vessels. In 98% of malignant and in 85% of benign lesions, vessels were detected. All flow criteria showed highly significant differences between benign and malignant tumors (p < 0.0001). However, there was a considerable overlap between benign and malignant tumors (e.g. the median of the lowest RI was 0.62 (range 0.26-1.0) for benign and 0.40 (0.22-0.66) for malignant tumors; the median of the maximum systolic velocity was 17.5 cm/s (range 5.2-61.5 cm/s) for benign and 47.05 cm/s (14.6-105.0 cm/s) for malignant tumors). Differentiation of malignant tumors by the lowest RI and PI, number of arteries and maximum of systolic flow velocities gave a sensitivity of 77-85%, specificity of 77-83% and accuracy of 80-84%. Differentiation was superior by calculation of the maximum end-diastolic velocities and by the summation of the systolic, end-diastolic and time-averaged maximum flow velocities: sensitivity 90-9.5% specificity 83-86% and accuracy 87-91%. This study confirms that a single measurement is not sufficient for an accurate differentiation of ovarian lesions and, besides the measurement of minimum RI and PI, the measurements of flow velocities as Doppler criteria play an important role.

[Color Doppler flow data of breast tumors]

The recent development of high-quality colour Doppler instruments allows flow detection in small vessels below the resolution of B-mode imaging. Therefore, Doppler is now frequently used for flow detection in tumours. For breast examinations, CW Doppler has been in use for many years, which allows a sufficient definition of diagnostic criteria. Nevertheless, it is surprising that new studies using colour Doppler try to define different diagnostic criteria. To characterise the vascularity of breast lesions by colour Doppler we investigated 127 symptomatic patients. In 54 carcinomas the average flow velocity was 32 cm/s and 12.6 cm/s in 73 benign conditions (p > 0.0001). Total tumour vascularisation was characterised by a new parameter: the sum of all flow velocities in all tumour vessels. In carcinomas the mean total flow as 197.9 cm/s, and 52.7 cm/s in benign pathologies (p > 0.0001). Mean RI (resistance index) and PI (pulsatility index) were calculated to describe the flow profiles. The wide variation did not allow for a differentiation between benign and malignant lesions.

Transvaginal sonography of myometrial invasion depth in endometrial cancer

The myometrial invasion depth of endometrial cancer is an important prognostic factor. The preoperative assessment is decisive for the appropriate surgical treatment. In 96 patients with endometrial cancer, the myometrial invasion depth (greater than 50% or less than 50%) was measured preoperatively using transvaginal sonography (TVS). The sonographic results were compared to the histopathological findings. A sensitivity of 93% was obtained for invasion depths greater than 50%. The predictive value of an invasion depth less than 50% was 93% as well. In 16% of the cases the invasion depth was overestimated while, in only 3% it was underestimated. The diagnostic accuracy was 81%. Forty-five patients were examined preceding a diagnostic dilatation and curettage and fifty-one were examined following a diagnostic dilatation and curettage. The diagnostic accuracy in both groups was equivalent. Using transvaginal sonography, the spread of cancer to the cervix was observed in five of the seven cases in which it was postoperatively confirmed. TVS is a valuable, non-invasive diagnostic method for patients with endometrial cancer. When the TVS data are combined with results from other preoperative tests, the prognostic information obtained provides a useful basis in choosing the appropriate therapy.