Which protocol for prostate biopsies in patients with a positive MRI? Interest of systematic biopsies by sectors.

BACKGROUND: Current prostate biopsy (PBx) protocol for prostate cancer (PCa) diagnosis is to perform systematic biopsies (SBx) combined with targeted biopsies (TBx) in case of positive MRI (i.e. PI-RADS ≥ 3). To assess the utility of performing SBx in combination with TBx, we determined the added value of SBx brought to the diagnosis of PCa according to their sextant location and MRI target characteristics. METHODS: In our local prospectively collected database, we conducted a single-center retrospective study including all patients with a suspicion of PCa, who underwent transrectal ultrasound-guided (TRUS) prostate biopsies (PBx) with a prior MRI and a single lesion classified as PI-RADS ≥ 3. We have characterized the SBx according to their location on MRI: same sextant (S-SBx), adjacent sextant (A-SBx), ipsilateral side (I-SBx) and contralateral side (C-SBx). The added value of SBx and TBx was defined as any upgrading to significant PCa (csPCa) (ISUP ≥2). RESULTS: 371 patients were included in the study. The added value of SBx was 10% overall. Regarding the lesion location and the SBx sextant, the added value of SBx was: 5.1% for S-SBx, 5.4% for A-SBx, 4.9% for I-SBx and 1.9% for C-SBx. The overall added value of SBx was 6.8% for PI-RADS 3 lesions, 14% for PI-RADS 4 lesions and 6.7% for PI-RADS 5 lesions (p = 0.063). The added value of SBx for contralateral side was 1.9% (2/103), 3.1% (5/163) and 0% (0/105) for PI-RADS 3, PI-RADS 4 and PI-RADS 5 lesions, respectively (p = 0,4). The added value of SBx was lower when the number of TBx was higher (OR 0.57; CI 95% 0.37-0.85; p = 0.007). CONCLUSIONS: Our results suggest that the utility of performing SBx in the contralateral lobe toward the MRI lesion was very low, supporting that they might be avoided.

Direct comparison between Grade Group assessed on systematic and MRI/ultrasound fusion targeted biopsies correlated to the radical prostatectomy specimens in patients with prostate cancer.

OBJECTIVES: To compare the correlation of Gleason score (GS) and ISUP grade determined by prostate biopsies (PBx) and radical prostatectomy (RP) specimens according to the biopsy technique: ultrasound randomised (RBx) vs. MRI/ultrasound fusion targeted (TBx). MATERIALS AND METHODS: Between March 2013 and June 2018, we retrospectively included patients who underwent RP for prostate cancer (PCa) histopathologically proven by RBx and/or TBx. All patients had a prebiopsy MRI by a single radiologist (using PI-RADS score), then transrectal RBx (12cores, blinded to MRI lesions) and TBx (2-4 cores/target) with elastic MRI/ultrasound fusion (UroStation™, Koelis, Grenoble, France). Histological findings were compared: PBx vs. RP. RESULTS: One hundred and four patients underwent RP after RBx and/or TBx. ISUP concordance rate was better with the association RBx+TBx 49% (51/104) vs. 43.3% with TBx (P=0.07) and 43.3% with RBx (P=0.13). With RBx, 50% of the patients were downgraded (52/104) against 42.3% (44/104) with TBx (P=0.088). The association RBx+TBx significantly decreased the rate of downgrading of the ISUP score compared to the ISUP score of RP 35.6% (37/104) vs. RBx (50%, P=0.0001) and vs. TBx (42.3%, P=0.016). CONCLUSION: In half of cases, the ISUP score was underestimated in RBx compared to RP specimens. Adding TBx to RBx significantly reduced downgrading. The combination of both biopsy techniques appeared to be the best protocol to get closer to ISUP score and GS of the RP specimens. LEVEL OF EVIDENCE: C.

[Morbidity of extended pelvic lymphadenectomy during robot-assisted laparoscopic prostatectomy for localized cancer prostate]. / Morbidité du curage ganglionnaire pelvien étendu au cours de la prostatectomie totale laparoscopique robot assistée.

OBJECTIVES: To assess the morbidity specific of extended pelvic lymphadenectomy during robot-assisted laparoscopic radical prostatectomy in a 8 year retrospective study. MATERIAL: We carried out a single-center, single-surgeon retrospective study on 342 consecutive patients who underwent a robot-assisted laparoscopic radical prostatectomy and extended pelvic lymphadenectomy, from July 2010 to March 2018. Postoperative complications were recorded up to 3 months after the operation. RESULTS: Thirty (8.8%) patients had at least one complication related to lymphadenectomy including 1 vascular injury (0.3%), 7 injuries of the obturator nerve (2%), 5 venous thromboembolic complications (1.5%) including 4 pulmonary embolisms, 10 symptomatic lymphoceles (2.9%) and 8 lymphoedemas (2.3%). Of these complications, 13 were classified Clavien 1 (43.3%), 8 Clavien 2 (26.7%), 7 Clavien 3a (23.3%) and 2 Clavien 3b (6.7%). In univariate analysis a high age (P=0.04), high BMI (P<0.01) and pT stage (P=0.02) were significantly associated with complication whereas in multivariate analysis, only age (P=0.02) and BMI (P<0.01) lived were. In univariate analysis high BMI (P=0.04) and lymph node involvement (P=0.04) were associated with lymphatic complication. We did not find any other specific risk factor for the other complications. CONCLUSION: With 8.8% of overall complications related to lymphadenectomy and 5% of complication classified Clavien grade 2 or higher, extended pelvic lymphadenectomy was not very morbid. Age and BMI were risk factors for a overall complication. BMI and lymph node involvement were risk factors for lymphatic complications. LEVEL OF PROOF: 4.

Laparoscopic Appendectomy Performed by junior SUrgeonS: impact of 3D visualization on surgical outcome. Randomized multicentre clinical trial. (LAPSUS TRIAL).

BACKGROUND: The purpose of this study was to evaluate the effect of 3D visualization applied to laparoscopic appendectomy (LA) performed by young surgeons (YS). We considered both operative features and clinical outcomes, aiming to highlight the benefits that this technology could bring to novice surgeons and their laparoscopic training. METHODS: All the surgical procedures were performed by residents who had performed less than 20 appendectomies prior to the beginning of the study under the supervision of an expert surgeon. At the time of enrolment patients were randomized into two arms: Experimental arm (EA): laparoscopic appendectomy performed with laparoscopic 3D vision technology. Control arm (CA): laparoscopic appendectomy performed with the "standard" 2D technology. The primary endpoint was to find any statistically significant difference in operative time between the two arms. Differences in conversion rate, intra-operative complications, post-operative complications and surgeons' operative comfort were considered as secondary endpoints. RESULTS: We randomized 135 patients into the two study arms. The two groups were homogeneous for demographic characteristics, BMI and ASA scores. The characteristics of clinical presentation and anatomical position showed no significant difference. The operative time was longer in the CA (57.5 vs. 49.6 min, p = 0.048, 95% CI). In the subgroup of complicated appendicitis, this trend toward inferior operative time was confirmed without reaching statistical significance (2D = 60 min, 3D = 49.5 min, p = 0.082 95% CI). No intra-operative complications were observed in either group. The conversion rate was 5.6% (4 patients) in the 2D group and 4.6% (3 patients) in 3D group. CONCLUSION: The utilization of 3D laparoscopy was associated with reduction in operative time without influencing other parameters, in particular without altering the safety profile of the procedure.

The role of tibial nerve stimulation for enhanced postoperative recovery after colorectal surgery: a double-blind, parallel-group, randomized controlled trial.

BACKGROUND: Postoperative ileus (POI) is the most common cause of prolonged hospital stay following abdominal surgery, despite an optimized enhanced recovery after surgery (ERAS) program. The aim of the study was to evaluate the role of postoperative transcutaneous electrical tibial nerve stimulation (TTNS) in the recovery of bowel function and in shortening hospital stay after colonic resection. METHODS: Patients having elective laparoscopic colonic surgery within an ERAS program at our institution between June 2016 and June 2019 were enrolled and randomly assigned to a treatment protocol with TTNS or sham electrical stimulation. The primary endpoint was the time of recovery of gastrointestinal motility, measured as the first passage of stool. Secondary endpoints included: first passage of flatus, length of hospital stay, and complication rate related to the use of TTNS. RESULTS: One hundred and seventy patients who had right hemicolectomy (median age 71 years (range 43-89 years); 47.5% women) and 170 patients who had left colectomy (median age 67 years range (37-92 years); 41.5% women) were enrolled. The only factor significantly affected by TTNS was time to first passage of flatus after right hemicolectomy (reduced from 46 to 33 h, p = 0.04). However, if only patients with low compliance to early oral nutrition (63 of 340; 18.5%) were considered, a statistically significant difference in time until first flatus (p < 0.01) and first bowel movement (p < 0.0001) and a shorter time until discharge (median 5 vs 7 days) were found in both left and right colectomies groups, respectively. CONCLUSIONS: TTNS may have a positive effect on gastrointestinal tract motility and recovery from POI after colorectal surgery in a selected group, who has low compliance with an ERAS program, without increasing the risk of complications.

Diagnostic and therapeutic role of laparoscopy in perforated peptic ulcer in the elderly patients.

AIM: The purpose of this study is to analyze the outcome of elderly patients with perforated peptic ulcer comparing laparoscopic treatment versus open approach. METHODS: In our General and Emergency Surgery Unit in the last 3 years, 20 elderly patients with perforated peptic ulcer were performed. We considered elderly all patients over the age of 65 years (10 females and 10 males; the mean age was 75 years). 16 patients (80%) were submitted to laparoscopic repair with omentoplasty and 4 (20%) to open repair. The patients were classified using the Boye's score which influenced the choice of surgical treatment and the outcoEmergency Romame. The two groups were compared in terms of operative surgery times, complication rate, mortality and postoperative outcomes. DISCUSSION: Perforated peptic ulcer is a common abdominal disease that is treated by surgery. The potential advantages of laparoscopy, both in terms of diagnosis and therapy, are clear and the major advantages may be observed in cases with peritonitis secondary as a perforated peptic ulcer where laparoscopy allows the confirmation of the diagnosis, the identification of the position of the ulcer and the repair. With the age the risks of comorbidities increases multidisease syndrome. Elderly patients suffer from frailty syndrome. All these factors make the elderly patient a major challenge for a laparoscopy treatment. CONCLUSION: The laparoscopic approach is an effective method for treatment of perforated peptic ulcer in the elderly with a great diagnostic and therapeutic role. Nowadays more prospective randomized studies are needed to evaluate the effectiveness of laparoscopic versus open repair.

Overexpression of certain transient receptor potential and Orai channels in prostate cancer is associated with decreased risk of systemic recurrence after radical prostatectomy.

BACKGROUND: Several studies had suggested the potential role of calcium signaling in prostate cancer (PCa) prognosis and agressiveness. We aimed to investigate selected proteins contributing to calcium (Ca2+ ) signaling, (Orai, stromal interaction molecule (STIM), and transient receptor potential (TRP) channels) and involved in cancer hallmarks, as independent predictors of systemic recurrence after radical prostatectomy (RP). METHODS: A case-control study including 112 patients with clinically localized PCa treated by RP between 2002 and 2009 and with at least 6-years' follow-up. Patients were divided into two groups according to the absence or presence of systemic recurrence. Expression levels of 10 proteins involved in Ca2+ signaling (TRPC1, TRPC4, TRPV5, TRPV6, TRPM8, STIM1, STIM2, Orai1, Orai2, and Orai3), were assessed by immunohistochemistry using tissue microarrays (TMAs) constructed from paraffin-embedded PCa specimens. The level of expression of the various transcripts in PCa was assessed using quantitative polymerase chain reaction (qPCR) analysis. RNA samples for qPCR were obtained from fresh frozen tissue samples of PCa after laser capture microdissection on RP specimens. Relative gene expression was analyzed using the 2-▵▵Ct method. RESULTS: Multivariate analysis showed that increased expression of TRPC1, TRPC4, TRPV5, TRPV6, TRPM8, and Orai2 was significantly associated with a lower risk of systemic recurrence after RP, independently of the prostate-specific antigen (PSA) level, percentage of positive biopsies, and surgical margin (SM) status (P = .007, P = .01, P < .001, P = .0065, P = .007, and P = .01, respectively). For TRPC4, TRPV5, and TRPV6, this association was also independent of Gleason score and pT stage. Moreover, overexpression of TRPV6 and Orai2 was significantly associated with longer time to recurrence after RP (P = .048 and .023, respectively). Overexpression of TRPC4, TRPV5, TRPV6, and Orai2 transcripts was observed in group R- (3.71-, 5.7-, 1.14-, and 2.65-fold increase, respectively). CONCLUSIONS: This is the first study to suggest the independent prognostic value of certain proteins involved in Ca2+ influx in systemic recurrence after RP: overexpression of TRPC1, TRPC4, TRPV5, TRPV6, TRPM8, and Orai2 is associated with a lower risk of systemic recurrence. TRPC4, TRPV5, and TRPV6 appear to be particularly interesting, as they are independent of the five commonly used predictive factors, that is, PSA, percentage of positive biopsies, SM status, Gleason score, and pT stage.

[Robotic-assisted laparoscopic implantation of artificial urinary sphincter AMS 800® in woman: Single center experience]. / Implantation du sphincter artificiel AMS 800® chez la femme par cœlioscopie robot-assistée : expérience monocentrique.

INTRODUCTION: Artificial urinary sphincter (AUS) is the treatment of last resort of stress urinary incontinence (UI) due to intrinsic sphincter deficiency (IS). The implantation procedure has been described by open surgery and laparoscopy with a significative rate of complication by Lucas et al. (2012) and Costa et al. (2001). We report our experience of implantation of SUA by robotic-assisted laparoscopy (R-SUA) in 17 patients among 3 revisions. MATERIAL AND METHODS: Between 2012 and 2017, 17 patients have been consecutively included. The surgical technique was described by Fournier et al. The continence was defined by the absence of urine leakage. RESULTS: The median age at implantation was 66,8±7 years, in the primo-implantation (PI) group, one patient had a neurological acontractile bladder, and bladder was open in 11 patients (78,6%) to ensure the bladder neck dissection. In the revision group (R) 3 patients had a complete replacement of SUA for mechanical failure. One vaginal bound was reported, but did not compromise the implantation, and the survival of SUA. Duration of intervention, size of cuff, postoperative catheterization and hospitalization time were respectively 205±34 and 112±8min; 7,7±0.9 and 5.2±0.8cm; 5.9±2.1 and 4.3±4 days; 6.6±1.5 and 7±3.6 days for PI and R groups. At the end of a mean follow-up of 24.6±18.4 and 59±5 months, continence was respectively 86% and 100%, for the PI and R groups. CONCLUSION: The implantation of R-SUA was feasible and safe with encouraging results. Other studies must evaluate the place of R-SUA among the different enabled surgical techniques. LEVEL OF EVIDENCE: 4.

Papain-treated panels are a simple method for the identification of alloantibodies in multiple myeloma patients treated with anti-CD38-based therapies.

OBJECTIVES: To report our 2 years of experience navigating the interference of anti-CD38 monoclonal antibodies (MAs) in 33 patients and describe papain-treated panels as a complementary method to dithiothreitol (DTT). BACKGROUND: Novel anti-CD38 MAs are now approved or undergoing clinical trials to evaluate their activity in patients with multiple myeloma. A concern with the use of these drugs is that they interfere with blood bank tests in a group of patients who often require blood transfusions. METHODS: Clinical data and whole blood samples were collected from patients receiving daratumumab or isatuximab. Routine blood bank serological tests were performed. RESULTS: A total of 9·1% of patients presented with alloantibodies prior to treatment. All patients exhibited nonspecific reactivity in indirect antiglobulin tests, and 26% had positive direct antiglobulin tests after beginning treatment. This interference disappeared in all patients after discontinuing treatment. Papain panels avoided this reactivity and allowed us to identify alloantibodies. Phenotyped blood units were transfused, and no patient suffered any transfusion-related complications. CONCLUSION: Anti-CD38 MAs produce nonspecific interference in blood bank tests. This interference can be overcome by various methods, including DTT or papain treatment as proposed here. These methods have limitations that can be resolved using phenotyped blood units.

Life-threatening bleeding for a large cameron ulcer. A novel description of a tailored-surgical strategy: report of a case and literature overview.

Hiatal hernias (HHs) are usually divided into two main groups: sliding and para-esophageal (torsional) ones. Sometimes patients presenting HHs experience progressive anemia, whereas rarely an acute anemia with melena or hematemesis can occur. In such cases a Cameron ulcer should be suspected and a careful esophago-gastro-duodenoscopy (EGDS) with a meticulous inspection of the mucosal folds along the neck of the hernia is the best examination in order to find out the ulcer itself. In front of massive hemorrhage due to a Cameron erosion, the first aim should be the control of the bleeding itself, in order to ree1Romastablish hemodynamic stability. The Authors report the case of a 72-year-old man presenting a severe bleeding secondary to a large Cameron ulcer in a para-esophageal hiatal hernia. Firstly, a combined medical-endoscopic therapy was tried; the patient underwent transfusions of pooled red blood cells and endovenous anti-acid therapy combined with an operative endoscopic treatment; unfortunately this initial approach failed, therefore the patient was referred to surgery. The surgeons realized a minimally invasive atypical gastric resection associated with the HH repair; the post-operative course was uneventful and no other rebleeding episodes occurred. The urgency treatment of a life-threatening bleeding for Cameron ulcers remains a very challenging problem as no univocal and standardized recommendation has been described in literature since now. In this case-report the Authors make an overview of the current literature on the treatment of Cameron ulcers, describing a novel surgical technique for massive upper gastro-intestinal bleeding secondary to these lesions.

A dramatic and rare complication: bowel perforation following abdominal liposuction.

AIM: The purpose of this study is to analyze a rare and under-reported complication of abdominal liposuction and the role of laparoscopy. CLINICAL CASE: We report a case of bowel perforation after 7 days of abdominal liposuction and bilateral mastopexy. The patient presented clinical and radiological findings of bowel obstructive syndrome and bilateral peripheral pulmonary embolism. An emergency diagnostic laparoscopy was performed and confirmed the diagnosis of bowel perforation. DISCUSSION: Bowel perforation is a known but under-reported comSOD Romaplication of abdominal liposuction, and it is characterized by a difficult diagnosis. The clinical presentation is characterized by a difficult diagnosis and severe complications. Bowel obstructive syndrome was constant, as our case and also peritonitis was never frank. This is an important point because it is one of the reasons for diagnostic delay. The development of laparoscopic surgery has changed the way to manage such conditions, where the diagnosis was doubt. In particular, when an acute abdomen occurs, laparoscopy may have three different roles: to confirm or not the diagnosis, to facilitate and guide a subsequent laparotomy or, finally, to entirely treat the disease. CONCLUSION: The bowel perforation is a dramatic and underestimated complication of abdominal liposuction. Diagnosis is complex. A clinical and radiological investigation should be quickly performed. In doubtful cases, an emergency laparoscopy can confirm the diagnosis and guide a possible subsequent laparotomy.

Role of transanal irrigation in the treatment of anterior resection syndrome.

BACKGROUND: Transanal irrigation(TAI) has been reported to be an inexpensive and effective treatment for low anterior resection syndrome(LARS). The aim of the present prospective study was to evaluate the use of TAI in patients with significant LARS symptoms at a single medical center. METHODS: Patients who had low anterior resection for rectal cancer between April 2015 and May 2016 at the Careggi University Hospital were assessed for LARS using the LARS and the Memorial Sloan-Kettering Cancer Center Bowel Function Instrument (MSKCC BFI) questionnaires 30-40 days after  surgery or ileostomy closure (if this was done). Quality of life was evaluated using a visual analog scale and the Short Form-36 Health Survey. All patients with LARS score of 30 or higher were included (early LARS) as were all patients with a LARS score of 30 or higher referred 6 months or longer after surgery performed elsewhere (chronic LARS) in the same study period. Study participants were trained to perform TAI using the Peristeen™ System for 6 months, followed by 3 months of enema therapy following a similar protocol. RESULTS: Thirty-three patients were enrolled in the study. Six patients stopped the treatment. The 27 patients (19 early LARS and 8 chronic LARS) who completed the study had a significant decrease in the number of median daily bowel movements [baseline 7 (range 0-14); 6 months 1 (range 0-4); 9 months 4 (range 0-13)]. The median LARS Score fell from 35.1 (range 30-42) (baseline) to 12.2 (range 0-21) after 6 months (p < 0.0001) and then rose to 27 (range 5-39) after 3 months of enema therapy. There was no difference in LARS score decrease at 6 months between the patients with early and chronic LARS (22.5 and 23.9 respectively; p=0.7) and there were no predictors of score decrease. Four components of the SF-36 significantly improved during the TAI period. The MSKCC BFI score significantly improved in several domains. Twenty-three patients (85%) asked to continue the treatment with TAI after the study ended. CONCLUSIONS: TAI appears to be an effective treatment for LARS and results in a marked improvement of continence and quality of life.  Patients may be assessed and treated for LARS early after surgery since the treatment benefit is similar to that observed in patients with LARS diagnosed  6 months or longer after surgery. The potential rehabilitative role of TAI for LARS is promising and should be further investigated.

[Outcomes of GreenLight XPS-180W laser photovaporization for BPH larger than 80mL]. / Résultats de la photovaporisation prostatique par laser GreenLight XPS-180W dans l'hyperplasie bénigne de prostate (HBP) de gros volume (≥80mL).

AIM: To evaluate the results of GreenLight XPS photovaporization (PVP/XPS) with intraoperative transrectal ultrasonographic monitoring for the treatment of large Benign Prostatic Hyperplasia (BPH) (>80mL). PATIENTS AND METHODS: Operative and perioperative data of 82 patients were collected prospectively. Complications and functional outcomes (IPSS, quality of life (QoL) score, maximal flow rate and post-void residual (PVR)) were evaluated at 1, 3, 12 months post-operatively prostate volume and PSA were assessed at 3 and 12 months post-operatively. RESULTS: Median patient age was 68.5years (50-85). Twenty percent had an indwelling catheter and 5%/22% were on anticoagulant/antiplatelet therapy. Median prostate volume and PSA were 103mL (80-220) and 6.4ng/mL (0.66-44.0). Median operative time and energy delivered were 107min (46-219) and 581kJ (212-1193). Energy delivered/prostate volume was 5.4kJ/mL (1.6-10.5). Transurethral catheter was removed at day 1 or 2 in 96% of cases. Patients were discharged as outpatient, p.o. day 1 or day 2 in 4%, 55% and 21% of cases, respectively. Transfusion and Clavien≥3 complication rates were 1.2% and 3.7%. Significant improvement of IPSS (4 vs 19.5), QoL (1 vs 5), maximum flow rate (19.1 vs 8.2mL/s) and PVR (26 vs 100mL) was observed (P<0.001) at 12-months evaluation. PSA and prostate volume were decreased by 61 and 62%. Late complications were urethral strictures (6%), stress incontinence (1.2%). Eighty-five percent of patients had no antegrade ejaculation. CONCLUSION: The treatment of large BPH with PVP/XPS is safe and effective, with a long operative time. The functional outcomes are good and stable at mid-term evaluation. LEVEL OF EVIDENCE: 4.

[Prevalence and diversity of management of prostate cancer patients classified as low risk using D'Amico group or Cancer of the Prostate Risk Assessment (CAPRA) score: A French multicenter study]. / Prévalence et diversité de la prise en charge des patients atteints de cancer de la prostate classés à faible risque selon la classification de d'Amico ou le score de CAPRA : étude française multicentrique.

OBJECTIVES: Currently, the French High Authority for Health does not recommend mass screening for prostate cancer (PCa), due to the risk of over-treatment, notably of low risk patients. Our study is intended to reflect the therapeutic attitudes for the management of patients classified as low risk of progression in French clinical centers. METHODS: For all positive prostate biopsies performed during 2012 and 2013 in five French departments of urology, clinicopathological characteristics required to calculate the d'Amico risk group and the Cancer of the Prostate Risk Assessment (CAPRA) score were filled. Information on the first treatment of "low risk" patients was collected. RESULTS: A total of 1035 patients were included, with a median age at diagnosis of 66 years old. According to d'Amico and CAPRA classifications, 30.4% and 35.0% of patients were at low, 34.5% and 33.2% at intermediate, 35.1% and 31.8% at high risk. The diagnosis severity increased with age (P<0.0001). The main treatment for low risk patients was radical prostatectomy (41.6% and 42.0% for d'Amico and CAPRA, respectively), but active surveillance was the most frequent treatment if diagnosed after 75 years old. The management of low risk patients varied significantly between centers (P<0.0001), according to the therapeutic platforms available within the hospital. CONCLUSIONS: In absence of strong progression predictor, the management of low risk PCa remains based on center habits and local therapeutic platforms. New predictive markers, such as multiparametric MRI or molecular tests, are needed to guide rational management of low risk PCa. LEVEL OF EVIDENCE: 4.

Modeling the impact of prostate edema on LDR brachytherapy: a Monte Carlo dosimetry study based on a 3D biphasic finite element biomechanical model.

Prostate volume changes due to edema occurrence during transperineal permanent brachytherapy should be taken under consideration to ensure optimal dose delivery. Available edema models, based on prostate volume observations, face several limitations. Therefore, patient-specific models need to be developed to accurately account for the impact of edema. In this study we present a biomechanical model developed to reproduce edema resolution patterns documented in the literature. Using the biphasic mixture theory and finite element analysis, the proposed model takes into consideration the mechanical properties of the pubic area tissues in the evolution of prostate edema. The model's computed deformations are incorporated in a Monte Carlo simulation to investigate their effect on post-operative dosimetry. The comparison of Day1 and Day30 dosimetry results demonstrates the capability of the proposed model for patient-specific dosimetry improvements, considering the edema dynamics. The proposed model shows excellent ability to reproduce previously described edema resolution patterns and was validated based on previous findings. According to our results, for a prostate volume increase of 10-20% the Day30 urethra D10 dose metric is higher by 4.2%-10.5% compared to the Day1 value. The introduction of the edema dynamics in Day30 dosimetry shows a significant global dose overestimation identified on the conventional static Day30 dosimetry. In conclusion, the proposed edema biomechanical model can improve the treatment planning of transperineal permanent brachytherapy accounting for post-implant dose alterations during the planning procedure.