Generative artificial intelligence in surgery.

Generative artificial intelligence is able to collect, extract, digest, and generate information in an understandable way for humans. As the first surgical applications of generative artificial intelligence are applied, this perspective paper aims to provide a comprehensive overview of current applications and future perspectives for the application of generative artificial intelligence in surgery, from preoperative planning to training. Generative artificial intelligence can be used before surgery for planning and decision support by extracting patient information and providing patients with information and simulation regarding the procedure. Intraoperatively, generative artificial intelligence can document data that is normally not captured as intraoperative adverse events or provide information to help decision-making. Postoperatively, GAIs can help with patient discharge and follow-up. The ability to provide real-time feedback and store it for later review is an important capability of GAIs. GAI applications are emerging as highly specialized, task-specific tools for tasks such as data extraction, synthesis, presentation, and communication within the realm of surgery. GAIs have the potential to play a pivotal role in facilitating interaction between surgeons and artificial intelligence.

The Impact of Telemedicine in Reducing the Carbon Footprint in Health Care: A Systematic Review and Cumulative Analysis of 68 Million Clinical Consultations.

CONTEXT: Carbon footprint (CF) has emerged as an important factor when assessing health care interventions. OBJECTIVE: To investigate the reduction in CF for patients utilizing telemedicine. EVIDENCE ACQUISITION: The PubMed, Scopus, and Web of Science databases were queried for studies describing telemedicine consultation and reporting on carbon emissions saved and the carbon emissions of telemedicine devices as primary outcomes, and travel distance and time and cost savings and safety as secondary outcomes. Outcomes were tabulated and calculated per consultation. Carbon emissions and travel distances were also calculated for each total study cohort. Risk of bias was assessed using the Newcastle-Ottawa scale, and the Oxford level of evidence was determined. EVIDENCE SYNTHESIS: A total of 48 studies met the inclusion criteria, covering 68 465 481 telemedicine consultations and savings of 691 825 tons of CO2 emissions and 3 318 464 047 km of travel distance. Carbon assessment was mostly reported as the estimated distance saved using a conversion factor. Medical specialties used telemedicine to connect specialists with patients at home (n = 25) or at a local center (n = 6). Surgical specialties used telemedicine for virtual preoperative assessment (n = 9), follow-up (n = 4), and general consultation (n = 4). The savings per consultation were 21.9-632.17 min and $1.85-$325. More studies focused on the COVID-19 time frame (n = 33) than before the pandemic (n = 15). The studies are limited by calculations, mostly for the travel distance for carbon savings, and appropriate follow-up to analyze the real impact on travel and appointments. CONCLUSIONS: Telemedicine reduces the CF of the health care sector. Expanding the use of telemedicine and educating providers and patients could further decrease CO2 emissions and save both money and time. PATIENT SUMMARY: We reviewed 48 studies on the use of telemedicine. We found that people used their cars less and saved time and money, as well as CO2 emissions, if they used teleconsultations. Some studies only looked at how much CO2 from driving was saved, so there might be more to learn about the benefits of teleconsultations. The use of online doctor appointments is not only good for our planet but also helps patients in saving time and money. This review is registered on the PROSPERO database for systematic reviews (CRD42023456839).

Consulting 'Dr. Google' for minimally invasive urological oncological surgeries: A contemporary web-based trend analysis.

PURPOSE: To determine web-based public interest in minimally invasive surgery (MIS) specifically for urological oncological surgical procedures and how interest in robotics and laparoscopy compares over time. MATERIALS AND METHODS: Worldwide search-engine trend analysis included electronic Google queries of MIS urologic options from January 2004 to August 2019, worldwide. Join-point regression was performed. Comparison of annual relative search volume (ARSV) and average annual percentage change (AAPC) were analysed to assess loss or gain of interest. Evaluations were made regarding 1) penetrance of interest for MIS in Urology; 2) how MIS urologic procedures compared over time; and 3) which were the top related queries to searches for urologic oncology procedures. RESULTS: Increased interest was found for all of the MIS procedures evaluated. Mean ARSV for robotic approach was higher for the search term 'prostatectomy" (44.8 vs. 13.5; p < 0.001) and 'partial nephrectomy" (27.1 vs.11.5; p = 0.02). No statistical difference was found for the search terms 'cystectomy" or 'nephrectomy". The analysis of mean (∆-ARSV) of MIS procedures measured between the first and last 12 months of the study period showed an increased interest with a more pronounced ∆-ARSV for robotic procedures. The top related searches for all surgical procedures were examined showing an increasing inquisitiveness with regards of type of urological cancers, treatment options, type of surgery and prognostic outcomes. CONCLUSIONS: People are increasingly searching the web for MIS urological procedures. A growing appeal for robotics is demonstrated, especially for prostatectomy and partial nephrectomy where the robotic approach is gaining traction, suggesting a shift in mind-set amongst people seeking urological healthcare information.

Objective risk stratification of prostate cancer using machine learning and radiomics applied to multiparametric magnetic resonance images.

Multiparametric magnetic resonance imaging (mpMRI) has become increasingly important for the clinical assessment of prostate cancer (PCa), but its interpretation is generally variable due to its relatively subjective nature. Radiomics and classification methods have shown potential for improving the accuracy and objectivity of mpMRI-based PCa assessment. However, these studies are limited to a small number of classification methods, evaluation using the AUC score only, and a non-rigorous assessment of all possible combinations of radiomics and classification methods. This paper presents a systematic and rigorous framework comprised of classification, cross-validation and statistical analyses that was developed to identify the best performing classifier for PCa risk stratification based on mpMRI-derived radiomic features derived from a sizeable cohort. This classifier performed well in an independent validation set, including performing better than PI-RADS v2 in some aspects, indicating the value of objectively interpreting mpMRI images using radiomics and classification methods for PCa risk assessment.

Focal therapy for prostate cancer: concepts and future directions.

PURPOSE OF REVIEW: To present a perspective on the current status and future directions of focal therapy for prostate cancer (PCa). RECENT FINDINGS: Focal therapy for localized PCa is a rapidly evolving field. Various recent concepts - the index lesion driving prognosis, the enhanced detection of clinically significant PCa using multiparametric MRI and targeted biopsy, improved risk-stratification using novel blood/tissue biomarkers, the recognition that reducing radical treatment-related morbidity (along with reducing pathologic progression) is a clinically meaningful end-point - have all led to a growing interest in focal therapy. Novel focal therapy modalities are being investigated, mostly in phase 1 and 2 studies. Recently, level I prospective randomized data comparing partial gland ablation with a standard-of-care treatment became available from one study. Recent developments in imaging, including 7-T MRI, functional imaging, radiomics and contrast-enhanced ultrasound show early promise. We also discuss emerging concepts in patient selection for focal therapy. SUMMARY: PCa focal therapy has evolved considerably in the recent few years. Overall, these novel focal therapy treatments demonstrate safety and feasibility, low treatment-related toxicity and acceptable short-term and in some cases medium-term oncologic outcomes. As imaging techniques evolve, patient selection, detection of clinically significant PCa and noninvasive assessment of therapeutic efficacy will be further optimized. The aspirational goal of achieving oncologic control while reducing radical treatment-related morbidity will drive further innovation in the field.

Diagnostic accuracy of a five-point Likert scoring system for magnetic resonance imaging (MRI) evaluated according to results of MRI/ultrasonography image-fusion targeted biopsy of the prostate.

OBJECTIVE: To evaluate the accuracy of a magnetic resonance imaging (MRI)-based Likert scoring system in the detection of clinically significant prostate cancer (CSPC), using MRI/ultrasonography (US) image-fusion targeted biopsy (FTB) as a reference standard. PATIENTS AND METHODS: We retrospectively reviewed 1218 MRI-detected lesions in 629 patients who underwent subsequent MRI/US FTB between October 2012 and August 2015. 3-Tesla MRI was independently reported by one of eight radiologists with varying levels of experience and scored on a five-point Likert scale. All lesions with Likert scores 1-5 were prospectively defined as targets for MRI/US FTB. CSPC was defined as Gleason score ≥7. RESULTS: The median patient age was 64 years, PSA level 6.97 ng/mL and estimated prostate volume 52.2 mL. Of 1218 lesions, 48% (n = 581) were rated as Likert 1-2, 35% (n = 428) were Likert 3 and 17% (n = 209) were Likert 4-5. For Likert scores 1-5, the overall cancer detection rates were 12%, 13%, 22%, 50% and 59%, respectively, and the CSPC detection rates were 4%, 4%, 12%, 33% and 48%, respectively. Grading using the five-point scale showed strong positive correlation with overall cancer detection rate (r = 0.949, P = 0.05) and CSPC detection rate (r = 0.944, P = 0.05). By comparison, in Likert 4-5 lesions, significant differences were noted in overall cancer detection rate (63% vs 35%; P = 0.001) and CSPC detection rate (47% vs 29%; P = 0.027) for the more experienced vs the less experienced radiologists. CONCLUSIONS: The detection rates of overall cancer and CSPC strongly correlated with the five-point grading of the Likert scale. Among radiologists with different levels of experience, there were significant differences in these cancer detection rates.

Does Computed Tomography Still Have Limitations to Distinguish Benign from Malignant Renal Tumors for Radiologists?

OBJECTIVES: To evaluate the current accuracy of CT for diagnosing benign renal tumors. MATERIALS AND METHODS: We retrospectively reviewed 905 patients who underwent preoperative CT followed by surgical resection. The final pathology was benign in 156 patients (17%). After exclusions, 140 patients with 163 benign tumors were included and 3 sets of the CT interpretations by radiologists with varying levels of experience were analyzed. RESULTS: The histological breakdown was as follows: oncocytomas (54.6%), angiomyolipomas (AMLs; 30.7%), renal cysts (8.0%), other miscellaneous benign tumors (6.7%). The sensitivities of diagnosing oncocytomas were 3.4, 9.0, and 13.5% in primary radiological reports, second blinded reviews, and third non-blinded reviews, respectively (p = 0.055). The sensitivities of diagnosing AMLs were 46.0, 58.0, and 62.0% in the 3-sets of CT interpretations, respectively (p = 0.246). As for renal cysts, the sensitivities were 69.2, 92.3, and 100% in the 3-sets of CT interpretations, respectively (p = 0.051). In primary reports, the positive predictive values were 95.8% in lipid poor (lp)-AMLs, 60.0% in oncocytomas, 69.2% in renal cysts, respectively (p < 0.05). CONCLUSIONS: Current conventional CT imaging still has limitations in differentiating oncocytomas and lp-AMLs from renal cell carcinomas, even when images were re-examined by experienced radiologists.

Robotic Intracorporeal Continent Cutaneous Diversion.

PURPOSE: Robotic intracorporeal urinary diversion has mostly been done for ileal conduit or orthotopic neobladder diversion. We present what is to our knowledge the initial series, detailed technique and outcomes of the robotic intracorporeal Indiana pouch with a minimum 1-year followup. MATERIALS AND METHODS: Ten patients underwent robotic radical cystectomy, pelvic lymphadenectomy and intracorporeal Indiana pouch urinary diversion for cancer in 9 and benign disease in 1. Data were collected prospectively. Baseline demographics, pathology data, and 1-year complication rates and functional outcomes were assessed. RESULTS: All 10 cases were successfully completed intracorporeally without open conversion. Median total operative time was 6 hours, including 3.5 hours for pouch creation. Median blood loss was 200 cc and median hospital stay was 10 days. Four Clavien grade 1-2 and 3 Clavien 3-5 complications occurred. None of the patients had a bowel leak. One noncompliant patient requested undiversion to an ileal conduit. The remaining 9 patients successfully catheterized the ileal channel and were completely continent at the last followup at a median of 13.7 months (range 12.3 to 15.2). Study limitations include small sample size and short followup. CONCLUSIONS: We present what is to our knowledge the initial series of robotic completely intracorporeal Indiana pouch diversion. Early perioperative data indicate acceptable operative efficiency and complication rates. Longer followup is required to assess the functional outcomes of this less commonly performed diversion.

Morphometric analysis of prostate zonal anatomy using magnetic resonance imaging: impact on age-related changes in patients in Japan and the USA.

OBJECTIVES: To evaluate the impact of morphometric magnetic resonance imaging (MRI) analysis of the prostate zonal anatomy on aging, prostatic hypertrophy and lower urinary tract symptoms in patients from Japan and the USA. SUBJECTS AND METHODS: A retrospective analysis of 307 men, including 156 men from Japan and 151 from the USA, who consecutively underwent 3-Tesla MRI and International Prostate Symptom Score (IPSS) assessment because of elevated PSA levels. Using Synapse-Vincent (Fujifilm), the prostatic zones were segmented in each axial step-section of the T2-weighted MRI to reconstruct a three-dimensional model of the prostate, which was used to calculate: zonal volumes (whole-gland prostate, transition zone and peripheral zone volumes); the presumed circle area ratio (PCAR); and PZ thickness. Bivariate associations were quantified using Spearman's rank correlation coefficients. RESULTS: The USA subgroup had a greater prostate volume (49 vs 42 mL; P = 0.003) and TZ volume (26 vs 20 mL; P < 0.001) than the Japan subgroup, with no difference in PZ volume (19 vs 20 mL; P = 0.2). There was no age-related increase in PZ volume in either of the subgroups or in the entire cohort (P = 0.9, P = 0.2, P = 0.3, respectively). PZ thickness had a significant negative correlation with PCAR (P < 0.001) and TZ volume (P < 0.001). The greater the increase in the TZ volume with the increase in PCAR, which probably correlates with obstructive pressure, the thinner the PZ became. PCAR had a significant positive correlation with IPSS (P = 0.003) and obstructive symptoms (P = 0.007), while PZ thickness had a significant negative correlation (P = 0.018). CONCLUSIONS: No age-related increases and no differences between the Japanese and the US subgroups were found with regard to PZ volume. The more TZ volume increased, the higher the obstructive pressure and the thinner the PZ became; these changes were associated with increased obstructive symptoms. MRI analysis of prostate zonal anatomy enhanced our understanding of age-related changes in morphology and urinary symptoms.

Detection of prostate cancer using magnetic resonance imaging/ultrasonography image-fusion targeted biopsy in African-American men.

OBJECTIVE: To assess the diagnostic yield of targeted prostate biopsy in African-American (A-A) men using image fusion of multi-parametric magnetic resonance imaging (mpMRI) with real-time transrectal ultrasonography (US). PATIENTS AND METHODS: We retrospectively analysed 661 patients (117 A-A and 544 Caucasian) who had mpMRI before biopsy and then underwent MRI/US image-fusion targeted biopsy (FTB) between October 2012 and August 2015. The mpMRIs were reported on a 5-point Likert scale of suspicion. Clinically significant prostate cancer (CSPC) was defined as biopsy Gleason score ≥7. RESULTS: After controlling for age, prostate-specific antigen level and prostate volume, there were no significant differences between A-A and Caucasian men in the detection rate of overall cancer (35.0% vs 34.2%, P = 0.9) and CSPC (18.8% vs 21.7%, P = 0.3) with MRI/US FTB. There were no significant differences between the races in the location of dominant lesions on mpMRI, and in the proportion of 5-point Likert scoring. In A-A men, MRI/US FTB from the grade 4-5 lesions outperformed random biopsy in the detection rate of overall cancer (70.6% vs 37.2%, P = 0.003) and CSPC (52.9% vs 12.4%, P < 0.001). MRI/US FTB outperformed random biopsy in cancer core length (5.0 vs 2.4 mm, P = 0.001), in cancer rate per core (24.9% vs 6.8%, P < 0.001), and in efficiency for detecting one patient with CSPC (mean number of cores needed 13.3 vs 81.9, P < 0.001), respectively. CONCLUSIONS: Our key finding confirms a lack of racial difference in the detection rate of overall prostate cancers and CSPC with MRI/US FTB between A-A and Caucasian men. MRI/US FTB detected more CSPC using fewer cores compared with random biopsy.

Evolution of robot-assisted orthotopic ileal neobladder formation: a step-by-step update to the University of Southern California (USC) technique.

OBJECTIVE: To describe our, step-by-step, technique for robotic intracorporeal neobladder formation. PATIENTS AND METHODS: The main surgical steps to forming the intracorporeal orthotopic ileal neobladder are: isolation of 65 cm of small bowel; small bowel anastomosis; bowel detubularisation; suture of the posterior wall of the neobladder; neobladder-urethral anastomosis and cross folding of the pouch; and uretero-enteral anastomosis. Improvements have been made to these steps to enhance time efficiency without compromising neobladder configuration. RESULTS: Our technical improvements have resulted in an improvement in operative time from 450 to 360 min. CONCLUSION: We describe an updated step-by-step technique of robot-assisted intracorporeal orthotopic ileal neobladder formation.

Robot-assisted Level II-III Inferior Vena Cava Tumor Thrombectomy: Step-by-Step Technique and 1-Year Outcomes.

BACKGROUND: Level II-III inferior vena cava (IVC) tumor thrombectomy for renal cell carcinoma is among the most challenging urologic oncologic surgeries. In 2015, we reported the initial series of robot-assisted level III caval thrombectomy. OBJECTIVE: To describe our University of Southern California technique in a step-by-step fashion for robot-assisted IVC level II-III tumor thrombectomy. DESIGN, SETTING, AND PARTICIPANTS: Twenty-five selected patients with renal neoplasm and level II-III IVC tumor thrombus underwent robot-assisted surgery with a minimum 1-yr follow-up (July 2011 to March 2015). SURGICAL PROCEDURE: Our standardized anatomic-based "IVC-first, kidney-last" technique for robot-assisted IVC thrombectomy focuses on minimizing the chances of an intraoperative tumor thromboembolism and major hemorrhage. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Baseline demographics, pathology data, 90-d and 1-yr complications, and oncologic outcomes at last follow-up were assessed. RESULTS AND LIMITATIONS: Robot-assisted IVC thrombectomy was successful in 24 patients (96%) (level III: n=11; level II: n=13); one patient was electively converted to open surgery for failure to progress. Median data included operative time of 4.5h, estimated blood loss was 240ml, hospital stay 4 d; five patients (21%) received intraoperative blood transfusion. All surgical margins were negative. Complications occurred in four patients (17%): two were Clavien 2, one was Clavien 3a, and one was Clavien 3b. All patients were alive at a 16-mo median follow-up (range: 12-39 mo). CONCLUSIONS: Robotic IVC tumor thrombectomy is feasible for level II-III thrombi. To maximize intraoperative safety and chances of success, a thorough understanding of applied anatomy and altered vascular collateral flow channels, careful patient selection, meticulous cross-sectional imaging, and a highly experienced robotic team are essential. PATIENT SUMMARY: We present the detailed operative steps of a new minimally invasive robot-assisted surgical approach to treat patients with advanced kidney cancer. This type of surgery can be performed safely with low blood loss and excellent outcomes. Even patients with advanced kidney cancer could now benefit from robotic surgery with a quicker recovery.

Utility of Ultrasound in the Diagnosis, Treatment, and Follow-up of Prostate Cancer: State of the Art.

Prostate cancer screening currently consists of serum prostate-specific antigen and digital rectal examination, followed by transrectal ultrasound-guided biopsy for diagnostic confirmation. Although the current paradigm of prostate cancer screening has led to a decrease in advanced disease and cancer-related mortality, these techniques have limitations in terms of sensitivity and specificity, resulting in missed cancers that are clinically significant and the overdetection of clinically insignificant cancers. New imaging techniques and technologies are required to improve the detection of prostate cancer. This article summarizes the use of novel ultrasound techniques and technologies in the detection, biopsy, and treatment of prostate cancer.

What Medical, Urologic, and Radiation Oncologists Want from Molecular Imaging of Prostate Cancer.

As molecular imaging better delineates the state of prostate cancer, clinical management will evolve. The currently licensed imaging modalities are limited by lack of specificity or sensitivity for the extent of cancer and for predicting outcome in response to therapy. Clinicians want molecular imaging that-by being more reliable in tailoring treatment and monitoring response for each patient-will become a key facet of precision medicine, surgery, and radiation therapy. Identifying patients who are candidates for specific or novel treatments is important, but equally important is the finding that a given patient may not be a good candidate for single-modality therapy. This article presents prostate cancer scenarios in which managing clinicians would welcome molecular imaging innovations to help with decision making. The potential role of newer techniques that may help fill this wish list is discussed.

Robotic transmural ablation of bladder tumors using high-intensity focused ultrasound: Experimental study.

OBJECTIVES: To evaluate the feasibility of robot-assisted laparoscopic high-intensity focused ultrasound for targeted, extravesical, transmural, full-thickness ablation of intact bladder wall and tumor. METHODS: In three fresh cadavers and one acute porcine model, the transperitoneal robotic approach was used to mobilize the bladder and create a midline cystotomy. "Mimic" bladder tumors (2 tumors/case) were created by robotically suturing a piece of striated muscle (2.5 × 2.5 cm) to the luminal, urothelial surface of the bladder wall. The cystotomy was suture-repaired and bladder distended with 250 mL saline. A laparoscopic high-intensity focused ultrasound probe was robotically placed extravesically in direct contact with the serosal surface of the bladder wall to image the "mimic" tumor. Targeted, transmural, full-thickness high-intensity focus ultrasound ablation of the "mimic" tumor and adjacent bladder was carried out under real-time ultrasound and robotic monitoring. Untreated areas of the bladder served as a comparison. Post-procedure, gross and microscopic examinations were carried out. RESULTS: Laparoscopic high-intensity focused ultrasound ablation was feasible for all "mimic" tumors (100%). Real-time ultrasound clearly visualized the "mimic" tumor. Simultaneous display of the pre-planning and real-time treatment ultrasound images confirmed targeting precision. Mean operative room times for ultrasound localization, laparoscopic high-intensity focused ultrasound probe coupling, high-intensity focus ultrasound ablation, and total procedure were 3, 5, 6 and 60 min, respectively. On necropsy, no thermal/mechanical injuries occurred to the untreated bladder wall, adjacent organs or ureters. Gross inspection distinguished the treated from untreated areas. Histopathology confirmed sharply demarcated thermal coagulative necrosis and shrinkage effects between the treated and untreated areas. CONCLUSIONS: Laparoscopic extravesical high-intensity focus ultrasound for transmural, full-thickness targeted ablation of intact bladder wall and tumor is feasible. This has implications for bladder-sparing surgery in select patients with solitary muscle-invasive bladder cancer.

Initial Series of Four-Arm Robotic Completely Intracorporeal Ileal Ureter.

Ileal ureter formation has been found to be a suitable treatment option for long, chronic ureteral strictures not amendable to less invasive forms of repair. Minimally invasive surgical techniques for this condition have been investigated. We report the first series of robotic completely intracorporeal ileal ureter using a four-arm robotic technique. Three patients underwent this procedure, including one patient with a solitary kidney. All procedures were performed effectively with a median operative time of 450 minutes (range: 420-540) and median estimated blood loss of 100 mL (range: 50-200). Postoperatively, one patient suffered volvulus and subsequent necrosis of small bowel and ileal ureter, which required re-operation and small bowel resection, including the ileal ureter. The other two patients report no surgical complications to date. This early series represents preliminary technical procedure feasibility. Further experience is necessary.

Personalized 3D printed model of kidney and tumor anatomy: a useful tool for patient education.

PURPOSE: To assess the impact of 3D printed models of renal tumor on patient's understanding of their conditions. Patient understanding of their medical condition and treatment satisfaction has gained increasing attention in medicine. Novel technologies such as additive manufacturing [also termed three-dimensional (3D) printing] may play a role in patient education. METHODS: A prospective pilot study was conducted, and seven patients with a primary diagnosis of kidney tumor who were being considered for partial nephrectomy were included after informed consent. All patients underwent four-phase multi-detector computerized tomography (MDCT) scanning from which renal volume data were extracted to create life-size patient-specific 3D printed models. Patient knowledge and understanding were evaluated before and after 3D model presentation. Patients' satisfaction with their specific 3D printed model was also assessed through a visual scale. RESULTS: After viewing their personal 3D kidney model, patients demonstrated an improvement in understanding of basic kidney physiology by 16.7 % (p = 0.018), kidney anatomy by 50 % (p = 0.026), tumor characteristics by 39.3 % (p = 0.068) and the planned surgical procedure by 44.6 % (p = 0.026). CONCLUSION: Presented herein is the initial clinical experience with 3D printing to facilitate patient's pre-surgical understanding of their kidney tumor and surgery.

Image-based monitoring of targeted biopsy-proven prostate cancer on active surveillance: 11-year experience.

PURPOSE: To report our 11-year experience of Active Surveillance (AS) program focusing on modern transrectal ultrasound (TRUS)-based monitoring of targeted biopsy-proven cancer lesion. METHODS: Consecutive patients on AS, who had targeted biopsy-proven lesion followed by at least a repeat surveillance biopsy and three times TRUS monitoring of the identical visible lesion, were included. Doppler grade of blood flow signal within the lesion was classified from grade 0 to 3. Biopsy-proven progression was defined as upgrade of Gleason score or 25% or greater increase in cancer core involvement. RESULTS: Fifty patients were included in this study. Clinical variables (median) included age (61 years), clinical stage (T1c, 42;T2, 8), PSA (4.6 ng/ml), and Gleason score (3 + 3, n = 41;3 + 4, n = 9). Of the 50 patients, 34 demonstrated pathological progression at a median follow-up of 4.4 years. In comparing between without (n = 16) and with (n = 34) pathological progression, there were significant differences in cancer core involvement at entry (p = 0.003), the major axis diameter (p = 0.001) and minor axis diameter (p = 0.001) of the visible lesion at entry, increase in the major axis diameter (p = 0.005) and minor axis diameter (p = 0.013), and upgrade of Doppler grade (p < 0.0001). In multivariate analysis for predicting pathological progression, the increase (≥25%) in diameter of biopsy-proven lesion (hazard ratio, 15.314; p = 0.023) and upgrade of Doppler grade (hazard ratio, 37.409; p = 0.019) were significant risk factors. CONCLUSIONS: Longitudinal monitoring of the TRUS-visible biopsy-proven cancer provides a new opportunity to perform per-lesion-based AS. The increase in diameter and upgrade of Doppler grade of the lesion were significant risk factors for biopsy-proven progression on AS.