Karim Touijer

Prostate Cancer: Identification with Combined Diffusion-weighted MR Imaging and 3D 1H MR Spectroscopic Imaging—Correlation with Pathologic Findings1

PURPOSE To retrospectively measure the mean apparent diffusion coefficient (ADC) with diffusion-weighted magnetic resonance (MR) imaging and the mean metabolic ratio (MET) with three-dimensional (3D) hydrogen 1 ((1)H) MR spectroscopic imaging in regions of interest (ROIs) drawn over benign and malignant peripheral zone (PZ) prostatic tissue and to assess ADC, MET, and combined ADC and MET for identifying malignant ROIs, with whole-mount histopathologic examination as the reference standard. MATERIALS AND METHODS The institutional review board approved this HIPAA-compliant retrospective study and issued a waiver of informed consent. From among 61 consecutive patients with prostate cancer, 38 men (median age, 61 years; range, 42-72 years) who underwent 1.5-T endorectal MR imaging before radical prostatectomy and who fulfilled all inclusion criteria of no prior hormonal or radiation treatment and at least one PZ lesion (volume, >0.1 cm(3)) at whole-mount pathologic examination were included. ADC maps were generated from diffusion-weighted MR imaging data, and MET maps of (choline plus polyamine plus creatine)/citrate were calculated from 3D (1)H MR spectroscopic imaging data. ROIs in the PZ identified by matching pathologic slides with T2-weighted images were overlaid on MET and ADC maps. Areas under the receiver operating characteristic curves (AUCs) were used to evaluate accuracy. RESULTS The mean ADC +/- standard deviation, (1.39 +/- 0.23) x 10(-3) mm(2)/sec, and mean MET (0.92 +/- 0.32) for malignant ROIs differed significantly from the mean ADC, (1.69 +/- 0.24) x 10(-3) mm(2)/sec, and mean MET (0.73 +/- 0.18) for benign ROIs (P < .001 for both). In distinguishing malignant ROIs, combined ADC and MET (AUC = 0.85) performed significantly better than MET alone (AUC = 0.74; P = .005) and was also better than ADC alone (AUC = 0.81), although the difference was not statistically significant (P = .09). CONCLUSION The combination of ADC and MET performs significantly better than MET for differentiating between benign and malignant ROIs in the PZ.

The Expanding Role of Partial Nephrectomy: A Critical Analysis of Indications, Results, and Complications

CONTEXT The gained expertise in the surgical technique of partial nephrectomy (PN) with excellent oncologic outcome and reduced morbidity has contributed to more frequent use of PN in many centres of reference, and the recent evidence favouring PN over radical nephrectomy (RN) in the prevention of chronic kidney disease and possibly linking it to a better overall survival (OS) will constitute a strong argument for wider use of PN. OBJECTIVE To objectively analyse the advantages of PN over RN and to evaluate the risk-benefit ratio of expanding the indications of PN T1b renal cortical tumours. EVIDENCE ACQUISITION Literature searches on English-language publications were performed using the National Library of Medicine database. The queries included the keywords partial nephrectomy and nephron sparing surgery. Eight hundred four references were scrutinised, and 175 publications were identified and reviewed. Sixty-nine articles were selected for this review. These references formed the basis for this analysis and were selected based on their relevance and the importance of their content. EVIDENCE SYNTHESIS The use of PN has been steadily increasing, particularly in tertiary care centres. This trend is now strengthened by evidence supporting the role of PN in reducing the risk of chronic kidney disease in patients with renal masses < or =4 cm. A wider use of PN for larger tumours, granted technical feasibility, is supported by the preliminary evidence, suggesting an OS advantage favouring PN over RN. However, the potential for selection bias and residual confounding factors may contribute to the observed difference. In the carefully selected patients with tumours >4 cm, PN obtained equivalent oncologic outcome to that achieved after RN. Although higher morbidity rates were seen after PN, the complication type and severity were not prohibitive. CONCLUSIONS The available evidence supports elective PN as the standard surgical treatment for renal cortical tumours < or =4 cm. For larger tumours, PN has demonstrated feasibility and oncologic safety in the carefully selected patient population studied.

Prostate Tumor Volume Measurement with Combined T2-weighted Imaging and Diffusion-weighted MR: Correlation with Pathologic Tumor Volume

PURPOSE To retrospectively determine the accuracy of diffusion-weighted (DW) magnetic resonance (MR) imaging for identifying cancer in the prostate peripheral zone (PZ) and to assess the accuracy of tumor volume measurements made with T2-weighted imaging and combined T2-weighted and DW MR imaging by using surgical pathologic examination as the reference standard. MATERIALS AND METHODS The institutional review board issued a waiver of informed consent for this HIPAA-compliant study. Forty-two patients underwent endorectal MR at 1.5 T before undergoing radical prostatectomy for prostate cancer and had at least one PZ tumor larger than 0.1 cm(3) at surgical pathologic examination. On T2-weighted images, an experienced radiologist outlined suspected PZ tumors. Two apparent diffusion coefficient (ADC) cutoff values were identified by using the Youden index and published literature. Image cluster analysis was performed on voxels within the suspected tumor regions. Associations between volume measurements from imaging and from pathologic examination were assessed by using concordance correlation coefficients (CCCs). The sensitivity and specificity of ADCs for identifying malignant PZ voxels were calculated. RESULTS In identifying malignant voxels, respective ADC cutoff values of 0.0014 and 0.0016 mm(2)/sec yielded sensitivity of 82% and 95% and specificity of 85% and 65%, respectively. Sixty PZ cancer lesions larger than 0.1 cm(3) were found at pathologic examination; 43 were detected by the radiologist. CCCs between imaging and pathologic tumor volume measurements were 0.36 for T2-weighted imaging, and 0.46 and 0.60 for combined T2-weighted and DW MR imaging with ADC cutoffs of 0.0014 and 0.0016 mm(2)/sec, respectively; the CCC of combined T2-weighted and DW MR imaging (ADC cutoff, 0.0016 mm(2)/sec) was significantly higher (P = .006) than that of T2-weighted imaging alone. CONCLUSION Adding DW MR to T2-weighted imaging can significantly improve the accuracy of prostate PZ tumor volume measurement. SUPPLEMENTAL MATERIAL http://radiology.rsnajnls.org/cgi/content/full/252/2/449/DC1.

Comprehensive Prospective Comparative Analysis of Outcomes Between Open and Laparoscopic Radical Prostatectomy Conducted in 2003 to 2005

PURPOSE In a nonrandomized prospective fashion we compared the oncological, functional and morbidity outcomes after laparoscopic and retropubic radical prostatectomy. MATERIALS AND METHODS Between January 2003 and December 2005 a total of 1,430 consecutive men with clinically localized prostate cancer underwent radical prostatectomy, laparoscopic in 612 and retropubic in 818. The surgical approach was selected by the patient. Preoperative staging, respective surgical techniques, pathological examination and followup were uniform. Functional outcome was measured by patient completed health related quality of life questionnaire. RESULTS Positive surgical margin rates (11%) and freedom from progression (median followup 18 months) were comparable between laparoscopic and retropubic radical prostatectomy (HR 0.99 for laparoscopic vs retropubic radical prostatectomy, p = 0.9). We found no significant association between operation type and time to postoperative potency (HR 1.04 for laparoscopic vs retropubic radical prostatectomy; 95% CI 0.74, 1.46; p = 0.8). Patients who underwent laparoscopic radical prostatectomy were less likely to become continent than those treated with retropubic radical prostatectomy (HR 0.56 for laparoscopic vs retropubic radical prostatectomy; 95% CI 0.44, 0.70; p <0.0005). Laparoscopic radical prostatectomy was associated with less blood loss (mean ml +/- SD 315 +/- 186 vs 1,267 +/- 660) and lower overall transfusion rate (3% vs 49%). No significant difference was noted in cardiovascular, thromboembolic and urinary complications. Emergency room visits and readmissions were higher after laparoscopic radical prostatectomy (15% vs 11% and 4.6% vs 1.2%, respectively). CONCLUSIONS At our institution and during the study period laparoscopic radical prostatectomy and retropubic radical prostatectomy provided comparable oncological efficacy. Laparoscopic radical prostatectomy was associated with less blood loss and a lower transfusion rate, and higher postoperative hospital visits and readmission rate. While the recovery of potency was equivalent, that of continence was superior after retropubic radical prostatectomy.

Contemporary Use of Partial Nephrectomy at a Tertiary Care Center in the United States

PURPOSE The use of partial nephrectomy for renal cortical tumors appears unacceptably low in the United States according to population based data. We examined the use of partial nephrectomy at our tertiary care facility in the contemporary era. MATERIALS AND METHODS Using our prospectively maintained nephrectomy database we identified 1,533 patients who were treated for a sporadic and localized renal cortical tumor between 2000 and 2007. Patients with bilateral disease or solitary kidneys were excluded from study and elective operation required an estimated glomerular filtration rate of 45 ml per minute per 1.73 m(2) or greater. Predictors of partial nephrectomy were evaluated using logistic regression models. RESULTS Overall 854 (56%) and 679 patients (44%) were treated with partial and radical nephrectomy, respectively. In the 820 patients treated electively for a tumor 4 cm or less the frequency of partial nephrectomy steadily increased from 69% in 2000 to 89% in 2007. In the 365 patients treated electively for a 4 to 7 cm tumor the frequency of partial nephrectomy also steadily increased from 20% in 2000 to 60% in 2007. On multivariate analysis male gender (p = 0.025), later surgery year (p <0.001), younger patient age (p = 0.005), smaller tumor (p <0.001) and open surgery (p <0.001) were significant predictors of partial nephrectomy. American Society of Anesthesiologists score, race and body mass index were not significantly associated with treatment type. CONCLUSIONS The use of partial nephrectomy is increasing and it is now performed in approximately 90% of patients with T1a tumors at our institution. For reasons that remain unclear certain groups of patients are less likely to be treated with partial nephrectomy.

Positive Surgical Margins After Radical Prostatectomy: A Systematic Review and Contemporary Update

CONTEXT The clinical significance of positive surgical margins (PSMs) in radical prostatectomy (RP) specimens and the management of affected patients remain unclear. OBJECTIVE To address pitfalls in the pathologic interpretation of margin status; provide an update on the incidence, predictors, and long-term oncologic implications of PSMs in the era of robot-assisted laparoscopic RP (RALRP); and suggest a practical evidence-based approach to patient management. EVIDENCE ACQUISITION A systematic review of the literature was performed in April 2013 using Medline/PubMed, Web of Science, and Scopus databases and the Cochrane Database of Systematic Reviews. Studies focusing on PSMs in RP pertinent to the objectives of this review were included. Particular attention was paid to publications within the last 5 yr and those concerning RALRP. EVIDENCE SYNTHESIS A total of 74 publications were retrieved. Standardized measures to overcome variability in the pathologic interpretation of surgical margins have recently been established by the International Society of Urological Pathology. The average rate of PSMs in contemporary RALRP series is 15% (range: 6.5-32%), which is higher in men with a more advanced pathologic stage and equivalent to the rate reported in prior open and laparoscopic prostatectomy series. The likelihood of PSMs is strongly influenced by the surgeons experience irrespective of the surgical approach. Technical modifications using the robotic platform and the role of frozen-section analysis to reduce the margin positivity rate continue to evolve. Positive margins are associated with a twofold increased hazard of biochemical relapse, but their association with more robust clinical end points is controversial. Level 1 evidence suggests that adjuvant radiation therapy (RT) may favorably affect prostate-specific antigen recurrence rates, but whether the therapy also affects systemic progression, prostate cancer-specific mortality, and overall survival remains debatable. CONCLUSIONS Although positive margins in prostate cancer are considered an adverse oncologic outcome, their long-term impact on survival is highly variable and largely influenced by other risk modifiers. Adjuvant RT appears to be effective, but further study is required to determine whether early salvage RT is an equivalent alternative.

Comprehensive Standardized Report of Complications of Retropubic and Laparoscopic Radical Prostatectomy

BACKGROUND The lack of standardized reporting of the complications of radical prostatectomy in the literature has made it difficult to compare incidences across institutions and across different surgical approaches. OBJECTIVE To define comprehensively the incidence, severity, and timing of onset of medical and surgical complications of open retropubic prostatectomy (RP) and laparoscopic radical prostatectomy (LP) using a standardized reporting methodology to facilitate comparison. DESIGN, SETTING, AND PARTICIPANTS Between January 1999 and June 2007, 4592 consecutive patients underwent RP or LP without prior radiation or hormonal therapy. Median follow-up was 36.9 mo (interquartile range: 20.3-60.6). INTERVENTION Open or laparoscopic radical prostatectomy. MEASUREMENTS All medical and surgical complications of radical prostatectomy were captured and graded according to the modified Clavien classification and classified by timing of onset. RESULTS AND LIMITATIONS There were 612 medical complications in 467 patients (10.2%) and 1426 surgical complications in 925 patients (20.1%). The overall incidences of early minor and major medical and surgical complications for RP were 8.5% and 1.5% for medical and 11.4% and 4.9% for surgical complications, respectively. The overall incidences of early minor and major medical and surgical complications for LP were 14.2% and 2.3% for medical and 23.1% and 6.6% for surgical complications, respectively. On multivariate analysis, LP approach was associated with a higher incidence of any grade medical and surgical complications but a lower incidence of major surgical complications than RP. Six hundred fifty-two men (14.2%) visited the emergency department, and 240 men (5.2%) required readmission. The main limitation is the retrospective nature. CONCLUSIONS With standardized reporting, the incidence of some complications is higher than recognized in the literature. Although most complications are minor in severity, medical and surgical complications are observed in approximately 10% and 20% of patients, respectively. Accurate reporting of complications through a standardized methodology is essential for counseling patients regarding risk of complications, for identifying modifiable risk factors, and for facilitating comparison across institutions and approaches.

Functional Magnetic Resonance Imaging in Prostate Cancer

CONTEXT Magnetic resonance imaging (MRI) combined with magnetic resonance spectroscopy imaging (MRSI), dynamic contrast-enhanced MRI, and diffusion-weighted MRI emerged as promising tests in the diagnosis of prostate cancer, and they show encouraging results. OBJECTIVE This review emphasizes different functional MRI techniques in the diagnosis of prostate cancer and includes information about their clinical value and usefulness. EVIDENCE ACQUISITION The authors searched the Medline, Embase, and Cochrane Library databases. There were no language restrictions. The last search was performed in October 2008. EVIDENCE SYNTHESIS The combination of conventional MRI with functional MRI techniques is more reliable for differentiating benign and malignant prostate tissues than any other diagnostic procedure. At present, no guideline is available that outlines which technique is best in a specific clinical situation. It also remains uncertain whether improved spatial resolution and signal-to-noise ratio of 3-T MRI will improve diagnostic performance. CONCLUSIONS A limited number of small studies suggest that functional MRI may improve the diagnosis and staging of prostate cancer. This finding needs further confirmation in larger studies, and cost-effectiveness needs to be established.

The Learning Curve for Laparoscopic Radical Prostatectomy: An International Multicenter Study

PURPOSE It is not yet possible to estimate the number of cases required for a beginner to become expert in laparoscopic radical prostatectomy. We estimated the learning curve of laparoscopic radical prostatectomy for positive surgical margins compared to a published learning curve for open radical prostatectomy. MATERIALS AND METHODS We reviewed records from 8,544 consecutive patients with prostate cancer treated laparoscopically by 51 surgeons at 14 academic institutions in Europe and the United States. The probability of a positive surgical margin was calculated as a function of surgeon experience with adjustment for pathological stage, Gleason score and prostate specific antigen. A second model incorporated prior experience with open radical prostatectomy and surgeon generation. RESULTS Positive surgical margins occurred in 1,862 patients (22%). There was an apparent improvement in surgical margin rates up to a plateau at 200 to 250 surgeries. Changes in margin rates once this plateau was reached were relatively minimal relative to the CIs. The absolute risk difference for 10 vs 250 prior surgeries was 4.8% (95% CI 1.5, 8.5). Neither surgeon generation nor prior open radical prostatectomy experience was statistically significant when added to the model. The rate of decrease in positive surgical margins was more rapid in the open vs laparoscopic learning curve. CONCLUSIONS The learning curve for surgical margins after laparoscopic radical prostatectomy plateaus at approximately 200 to 250 cases. Prior open experience and surgeon generation do not improve the margin rate, suggesting that the rate is primarily a function of specifically laparoscopic training and experience.

Metastatic Renal Cell Carcinoma Risk According to Tumor Size

PURPOSE Recent evidence suggests significantly discordant findings regarding tumor size and the metastasis risk in renal cell carcinoma cases. We present our experience with renal cell carcinoma. We evaluated the association between tumor size and the metastasis risk in a large patient cohort. MATERIALS AND METHODS Using our prospectively maintained nephrectomy database we identified 2,691 patients who were treated surgically for a sporadic renal cortical tumor between 1989 and 2008. Associations between tumor size and synchronous metastasis at presentation (M1 renal cell carcinoma) were evaluated with logistic regression models. Metastasis-free survival after surgery was estimated using the Kaplan-Meier method in 2,367 patients who did not present with M1 renal cell carcinoma and were followed postoperatively. RESULTS Of the 2,691 patients 162 presented with metastatic renal cell carcinoma. Only 1 of 781 patients with a tumor less than 3 cm had M1 renal cell carcinoma at presentation and tumor size was significantly associated with metastasis at presentation (for each 1 cm increase OR 1.25, p <0.001). Of the 2,367 patients who did not present with metastasis metastatic disease developed in 171 during a median 2.8-year followup. In this group only 1 of the 720 patients with renal cell carcinoma less than 3 cm showed de novo metastasis during followup. Metastasis-free survival was significantly associated with tumor size (for each 1 cm increase HR 1.24, p <0.001). CONCLUSIONS In our experience tumor size is significantly associated with synchronous and asynchronous metastases after nephrectomy. Our results suggest that the risk of metastatic disease is negligible in patients with tumors less than 3 cm.