Radiomics based on biparametric MRI for the detection of significant residual prostate cancer after androgen deprivation therapy: using whole-mount histopathology as reference standard.

We aimed to study radiomics approach based on biparametric magnetic resonance imaging (MRI) for determining significant residual cancer after androgen deprivation therapy (ADT). Ninety-two post-ADT prostate cancer patients underwent MRI before prostatectomy (62 with significant residual disease and 30 with complete response or minimum residual disease [CR/MRD]). Totally, 100 significant residual, 52 CR/MRD lesions, and 70 benign tissues were selected according to pathology. First, 381 radiomics features were extracted from T2-weighted imaging, diffusion-weighted imaging, and apparent diffusion coefficient (ADC) maps. Optimal features were selected using a support vector machine with a recursive feature elimination algorithm (SVM-RFE). Then, ADC values of significant residual, CR/MRD lesions, and benign tissues were compared by one-way analysis of variance. Logistic regression was used to construct models with SVM features to differentiate between each pair of tissues. Third, the efficiencies of ADC value and radiomics models for differentiating the three tissues were assessed by area under receiver operating characteristic curve (AUC). The ADC value (mean ± standard deviation [s.d.]) of significant residual lesions ([1.10 ± 0.02] × 10-3 mm2 s-1) was significantly lower than that of CR/MRD ([1.17 ± 0.02] × 10-3 mm2 s-1), which was significantly lower than that of benign tissues ([1.30 ± 0.02] × 10-3 mm2 s-1; both P < 0.05). The SVM feature models were comparable to ADC value in distinguishing CR/MRD from benign tissue (AUC: 0.766 vs 0.792) and distinguishing residual from benign tissue (AUC: 0.825 vs 0.835) (both P > 0.05), but superior to ADC value in differentiating significant residual from CR/MRD (AUC: 0.748 vs 0.558; P = 0.041). Radiomics approach with biparametric MRI could promote the detection of significant residual prostate cancer after ADT.

Quantitative dynamic contrast-enhanced MR imaging for the preliminary prediction of the response to gemcitabine-based chemotherapy in advanced pancreatic ductal carcinoma.

PURPOSE: To investigate the role of the quantitative parameters of dynamic contrast-enhanced MR imaging (DCE-MRI) in the prediction of the response to chemotherapy in pancreatic ductal carcinoma (PDC). METHOD: Forty patients with histologically confirmed PDC who underwent quantitative DCE-MRI were retrospectively analyzed. All patients were divided into groups of responders and nonresponders. DCE-MRI parameters, including the volume transfer constant (Ktrans), the extracellular extravascular volume fraction (ve), the rate constant (kep) and the initial area under the concentration curve in 60 s (iAUC60), were measured and compared. DCE-MRI parameters were obtained from different ROIs. RESULTS: The values of Ktrans in responders with peripheral, whole tumor slice, and adjacent non-tumorous region ROIs were significantly higher than those in nonresponders (P = 0.015, 0.043, and 0.025, respectively). Responders showed a significantly higher kep with peripheral area ROI compared with nonresponders (P =  0.013). Ve and iAUC60 with all ROIs were not significantly different between responders and nonresponders (P = 0.140-0.968). Kep with periphery ROI showed the highest area under the ROC curve (AUC) of 0.806, but there were no statistical differences when compared with values of Ktrans.There were statistically significant differences for DCE-MRI parameters among four ROIs (all P <  0.05). All parameters showed good to excellent intra and interobserver agreement. CONCLUSIONS: Quantitative parameters derived from DCE-MRI might be a potential predictor of response to gemcitabine in patients with PDC. Perfusion parameters were diverse depending on the location of the ROI on different tumoral and peritumoral areas.

Tumor growth velocity: A modified tumor growth rate defining tumor progression during sorafenib treatment in patients with metastatic renal cell carcinoma.

OBJECTIVES: To investigate the role of tumor growth velocity in defining tumor progression in metastatic renal cell carcinoma patients treated with the vascular endothelial growth factor tyrosine kinase inhibitor, sorafenib. METHODS: A modified calculation for tumor growth velocity was introduced to evaluate the tumor growth velocity, before and after sorafenib withdrawal. Known prognostic factors together with tumor growth velocity before drug withdrawal and tumor growth velocity after drug withdrawal were compared using a χ2 -test from a contingency table, and partial likelihood test from a Cox regression model for overall survival. RESULTS: A total of 114 patients who reached progressive disease and withdrew from sorafenib were enrolled after a median follow-up period of 107.8 months. Tumor growth velocity before drug withdrawal was 7.347 ± 4.040, and tumor growth velocity after drug withdrawal was 11.647 ± 5.937 (P < 0.001). Higher tumor growth velocity before drug withdrawal was correlated with a higher risk Memorial Sloan Kettering Cancer Center score (P = 0.022), Karnofsky Performance Status <80 (P = 0.028), non-clear cell carcinoma (P = 0.037), higher tumor nucleus grade (P < 0.001) and best treatment response (P < 0.001). Patients with tumor growth velocity before drug withdrawal >5.0 had shorter overall survival (P < 0.001). On multivariate analysis, factors associated with overall survival were high/intermediate Memorial Sloan Kettering Cancer Center risk score (hazard ratio 2.119, P = 0.006), non-clear histological subtype (hazard ratio 1.900, P = 0.031), tumor growth velocity before drug withdrawal ≥5.0 (hazard ratio 2.758, P < 0.001) and progressive disease as best response (hazard ratio 2.069, P = 0.001). CONCLUSIONS: Significantly faster tumor growth can be observed if sorafenib is discontinued in the case of disease progression. Thus, we suggest not to withdraw targeted agents until tumor growth velocity is >5.0.

Adrenal schwannoma: CT, MR manifestations and pathological correlation.

OBJECTIVES: This study aimed to describe the computed tomography (CT), magnetic resonance imaging (MRI) imaging features of adrenal schwannoma and to correlate imaging findings with histopathologic findings. METHODS: The findings from multiphase CT or MRI examinations of seventeen patients with histopathologically confirmed adrenal schwannoma were reviewed. The imaging criteria included shape, size, margin, attenuation, signal intensity, secondary degeneration, and internal mass enhancement pattern. RESULTS: All cases were unilateral, round or oval solitary tumors, with diameters ranging from approximately 2.5 to 8.8 cm (median = 4.5 cm). Of the twelve cases assessed using CT, adrenal schwannoma appeared as well-circumscribed round or oval low-density suprarenal masses with a mean attenuation values of 30.1 HU of solid portions during unenhanced phase. Ten cases exhibited heterogeneous cyst formation, and one case showed calcification. Internal septa were noted in 5 cases. All solid areas displayed early mild heterogeneous enhancement and delayed progressive enhancement. Regarding MRI, solid portions of five masses were hypointense to the liver parenchyma on T1-weighted imaging (T1WI) and were heterogeneously hyperintense on T2-weighted imaging (T2WI). The enhanced pattern of solid areas of adrenal schwannoma on MRI is similar to that of CT. Cystic or hemorrhagic changes were noted in 4 cases and internal septa were noted in 3 cases. CONCLUSION: Although schwannoma is a rare entity in the adrenal gland, we believe that the following signs may suggest the diagnosis of this entity: a non-lipid containing mass, a well-defined border, a unilateral mass with cystic or hemorrhagic degeneration, septa with delayed enhancement and a characteristic progressive contrast enhancement pattern of the solid portions.

Clinicopathological and prognostic factors for long-term survival in Chinese patients with metastatic renal cell carcinoma treated with sorafenib: a single-center retrospective study.

Data on long-term survival and prognostic significance of demographic factors and adverse events (AEs) associated with sorafenib, an orally administered multikinase inhibitor in Chinese population with advanced renal cell carcinoma (RCC) are limited. Outcome data from adult patients (n = 256) with advanced RCC who received sorafenib (400 mg twice daily) either as first-line or second-line therapy between April 2006 and May 2013 were analyzed retrospectively. The primary endpoint was median overall survival (OS), determined to be 22.2 (95% CI: 17.1-27.4) months, and the secondary endpoint was overall median progression-free survival (PFS), determined to be 13.6 (95% CI: 10.7-16.4) months at a median follow-up time of 61.8 (95% CI: 16.2-97.4) months. Analysis of the incidence of AEs revealed the most common side effect as hand-foot skin reactions (60.5%) followed by diarrhea (38.7%), fatigue (35.5%), alopecia (34.0%), rash (24.6%), hypertension (21.5%) and gingival hemorrhage (21.1%). Multivariate regression analysis revealed older age (≥ 58 years), lower Memorial Sloan-Kettering Cancer Center score, time from nephrectomy to sorafenib treatment, number of metastatic tumors and best response as significant and independent demographic predictors for improved PFS and/or OS (p ≤ 0.05). Alopecia was identified as a significant and independent predictor of increased OS, whereas vomiting and weight loss were identified as significant predictors of decreased OS (p ≤ 0.05). Sorafenib significantly improved OS and PFS in Chinese patients with advanced RCC. Considering the identified significant prognostic demographic factors along with the advocated prognostic manageable AEs while identifying treatment strategy may help clinicians select the best treatment modality and better predict survival in these patients.

Visceral obesity and risk of high grade disease in clinical t1a renal cell carcinoma.

PURPOSE: Accurate assessment of disease characteristics is a prerequisite for treatment decision making regarding small renal masses. In this study we evaluate the association between visceral obesity and Fuhrman grade in patients with cT1a renal cell carcinoma. MATERIALS AND METHODS: We retrospectively collected data on 186 patients with surgically treated cT1a renal cell carcinoma. Single slice computerized tomography was used to measure the area of visceral and subcutaneous adipose tissue. Visceral obesity was calculated as the proportion of visceral adipose tissue to overall adipose tissue. Other analyzed factors included clinical characteristics (age, gender, body mass index and tumor size) and anatomical features of the tumor defined by the R.E.N.A.L. nephrometry score. The association between predictors and high grade disease (Fuhrman grade III or IV) were assessed using logistic regression analyses. RESULTS: A total of 47 (25.3%) tumors were classified as high grade. The percentage of visceral adipose tissue was higher in male participants but did not correlate with body mass index, age or tumor size. In univariate analyses the percentage of visceral adipose tissue and tumor size were significantly associated with higher Fuhrman grade. Multivariate analysis showed that the percentage of visceral adipose tissue (OR 1.06, p = 0.0018) and tumor size (OR 1.91, p = 0.047) were independent predictors of high grade cancer. Addition of the percentage of visceral adipose tissue to a model including clinical characteristics and anatomical features of the tumor remarkably improved its discriminatory ability (p = 0.0010). CONCLUSIONS: Increased visceral obesity was found to be strongly associated with higher Fuhrman grade in patients with cT1a renal cell carcinoma. Further studies are needed to confirm these findings and discover the underlying biological mechanism.

[The value of diffusion-weighted MR imaging combined with transrectal ultrasound for transrectal prostate biopsy].

OBJECTIVE: To retrospectively analyze the clinical value of diffusion-weighted MR imaging in the detection of prostate cancer in suspected patients. METHODS: Between January 2009 and December 2010, the 551 patients suspected as prostate cancer underwent prostate biopsy. Patients in group A were accepted to a transrectal ultrasound (TRUS) guided transrectal prostate biopsy (n = 410), while patients in group B were accepted to a diffusion weighted imaging (DWI) and TRUS jointly guided transrectal prostate biopsy (n = 141). The two groups were divided into 4 subgroups by prostate specific antigen (PSA) < 10 µg/L, 10 µg/L ≤ PSA < 20 µg/L, 20 µg/L ≤ PSA < 50 µg/L and PSA ≥ 50 µg/L. Then, the diagnostic rates of prostate biopsy guided by combination of DWI and TRUS with only TRUS were compared. RESULTS: The diagnostic rate of patients with PSA < 10 µg/L, 10 µg/L ≤ PSA < 20 µg/L, 20 µg/L ≤ PSA < 50 µg/L and PSA ≥ 50 µg/L were 12.1%, 31.1%, 48.0%, 91.2% in group A, and 23.7%, 35.5%, 66.7%, 96.3% in group B, respectively. In the patients with PSA less than 10 µg/L, there were significant differences in diagnostic rate between the two biopsy techniques (χ(2) = 4.405, P < 0.05). CONCLUSION: The combination of DWI and TRUS showed the potential to guide biopsy to cancer foci in patients suspected as prostate cancer. For patients with PSA < 10 µg/L, a DWI and TRUS jointly guided transrectal prostate biopsy was recommended.

[Combined usage of diffusion-weighted magnetic resonance imaging and transrectal ultrasound for transrectal prostate biopsy: a preliminary study].

OBJECTIVE: To retrospectively analyze the clinical value of diffusion-weighted magnetic resonance imaging (MRDWI) in the detection of prostate cancer in suspected patients. METHODS: Between January 2009 and December 2010, 141 patients with suspected prostate cancer underwent MRDWI and transrectal ultrasound (TRUS) guided prostate biopsy. They were divided into 4 groups by prostate surface antigen (PSA) < 10 µg/L, 10 µg/L ≤ PSA < 20 µg/L, 20 µg/L ≤ PSA < 50 µg/L and PSA ≥ 50 µg/L. Then the diagnostic accuracy of MRDWI was tested. RESULTS: The diagnostic rate of patients with PSA < 10 µg/L, 10 µg/L ≤ PSA < 20 µg/L, 20 µg/L ≤ PSA < 50 µg/L and PSA ≥ 50 µg/L were 23.7%, 35.5%, 66.7% and 96.3% respectively. The sensitivity of MRDWI was significantly better than TRUS. In patients with PSA < 10 µg/L, 10 µg/L ≤ PSA < 20 µg/L, 20 µg/L ≤ PSA < 50 µg/L and PSA ≥ 50 µg/L, the patient-based sensitivities were 85.7%, 72.7%, 97.8%, 100.0% respectively; when based by segment of specimen, the sensitivities were 85.5%, 71.9%, 91.5% and 94.4% respectively. CONCLUSION: The sensitivity of MDWI is significantly better than TRUS in the diagnosis of prostate cancer. The combined use of MDWI and TRUS has the benefit of guiding the biopsy of cancer foci in patients with suspected prostate cancer.