Multispectral Photoacoustic Imaging of Prostate Cancer: Preliminary Ex-vivo Results

OBJECTIVE

The objective of this study is to validate if ex-vivo multispectral photoacoustic (PA) imaging can differentiate between malignant prostate tissue, benign prostatic hyperplasia (BPH), and normal human prostate tissue.

MATERIALS AND METHODS

Institutional Review Board's approval was obtained for this study. A total of 30 patients undergoing prostatectomy for biopsy-confirmed prostate cancer were included in this study with informed consent. Multispectral PA imaging was performed on surgically excised prostate tissue and chromophore images that represent optical absorption of deoxyhemoglobin (dHb), oxyhemoglobin (HbO2), lipid, and water were reconstructed. After the imaging procedure is completed, malignant prostate, BPH and normal prostate regions were marked by the genitourinary pathologist on histopathology slides and digital images of marked histopathology slides were obtained. The histopathology images were co-registered with chromophore images. Region of interest (ROI) corresponding to malignant prostate, BPH and normal prostate were defined on the chromophore images. Pixel values within each ROI were then averaged to determine mean intensities of dHb, HbO2, lipid, and water.

RESULTS

Our preliminary results show that there is statistically significant difference in mean intensity of dHb (P < 0.0001) and lipid (P = 0.0251) between malignant prostate and normal prostate tissue. There was difference in mean intensity of dHb (P < 0.0001) between malignant prostate and BPH. Sensitivity, specificity, positive predictive value, and negative predictive value of our imaging system were found to be 81.3%, 96.2%, 92.9% and 89.3% respectively.

CONCLUSION

Our preliminary results of ex-vivo human prostate study suggest that multispectral PA imaging can differentiate between malignant prostate, BPH and normal prostate tissue.

Modifications to facilitate extraperitoneal robot-assisted radical prostatectomy post kidney transplant

Extraperitoneal robotic-assisted radical prostatectomy in carefully selected renal allograft recipients may be feasible in avoiding injury to the renal allograft, transplanted ureter, and ureteroneocystostomy.

Introduction:

Renal transplantation is the treatment of choice for patients with end-stage renal failure. With advances in immunosuppression, the short-term and long-term outcome has improved significantly. Subsequently, urologists are encountering more transplant recipients with genitourinary malignancies, and therefore urologists are becoming increasingly compelled to offer curative treatment options.

Materials and Methods:

We present modifications to facilitate E-RARP in these patients that include modified trocar arrangement, delayed bladder neck transection, utilizing the robotic Hem-o-lok applier, and posterior reconstruction of the anastomosis using a barbed V-loc suture. A 68-year-old male with a history of polycystic kidney disease, end-stage renal failure, and an allograft renal transplantation in the right iliac fossa, presented with T1c, Gleason 3+4 prostate cancer. He had a preoperative PSA of 6.93ng/mL, ASA score of 3, and a BMI of 26kg/m². Follow-up for metastasis (MRI and bone scan) was negative. E-RARP was performed via the extraperitoneal approach using a 5-port 2-arm approach at an insufflation pressure of 10mm Hg.

Results:

The radical prostatectomy was successfully performed. Ureterovesical anastomosis was completed, and total console time was 130 minutes, with an estimated blood loss of 125mL. Final pathology was T2bNx, Gleason 3+4 with negative surgical margins. The patient was discharged with no change in serum creatinine or GFR. The catheter was removed on POD 10 with no intraoperative or immediate postoperative complications.

Conclusion:

E-RARP in the carefully selected renal allograft recipient is feasible and accomplished safely with technical modifications to avoid injuring the renal allograft, transplanted ureter, and ureteroneocystostomy.

Inhibition of formyl peptide receptor in high-grade astrocytoma by CHemotaxis Inhibitory Protein of S. aureus

Background:

High-grade astrocytomas are malignant brain tumours that infiltrate the surrounding brain tissue and have a poor prognosis. Activation of formyl peptide receptor (FPR1) on the human astrocytoma cell line U87 promotes cell motility, growth and angiogenesis. We therefore investigated the FPR1 inhibitor, Chemotaxis Inhibitory Protein of S. aureus (CHIPS), as a potential anti-astrocytoma drug.

Methods and results:

FPR1 expression was studied immunohistochemically in astrocytomas WHO grades I–IV. With intracellular calcium mobilisation and migration assays, human ligands were tested for their ability to activate FPR1 on U87 cells and on a cell line derived from primary astrocytoma grade IV patient material. Thereafter, we selectively inhibited these ligand-induced responses of FPR1 with an anti-inflammatory compound called Chemotaxis Inhibitory Protein of S. aureus (CHIPS). U87 xenografts in NOD-SCID mice served to investigate the effects of CHIPS in vivo. FPR1 was expressed in 29 out of 32 (90%) of all grades of astrocytomas. Two human mitochondrial-derived formylated peptides, formyl-methionil-leucine-lysine-isoleucine-valine (fMLKLIV) and formyl-methionil-methionil-tyrosine-alanine-leucine-phenylalanine (fMMYALF), were potent activators of FPR1 on tumour cells. Ligand-induced responses of FPR1-expressing tumour cells could be inhibited with FPR1 inhibitor CHIPS. Treatment of tumour-bearing mice with CHIPS slightly reduced tumour growth and improved survival as compared to non-treated animals (P=0.0019).

Conclusion:

Targeting FPR1 with CHIPS reduces cell motility and tumour cell activation, and prolongs the survival of tumour-bearing mice. This strategy could be explored in future research to improve treatment results for astrocytoma patients.

Laparoscopic salvage total pelvic exenteration: Is it possible post-chemo-radiotherapy?

Indications for total pelvic exenteration in a male (removal of the bladder, prostate and rectum) and in a woman (removal bladder, uterus, vagina, ovaries and rectum) are rare. The advanced stage generally dictates that the patient has some form of chemotherapy or radiotherapy, or a combination of two to shrink/debulk the tumour. We report the first two cases of a salvage laparoscopic total pelvic exenteration in a male for rectal adenocarcinoma invading into the bladder and prostate, post-chemo-radiotherapy and in a woman for squamous cell carcinoma of cervix invading the bladder and rectum post-chemo-radiotherapy. Salvage surgery is often difficult and has been noted to have high morbidity. Applying a laparoscopic approach to this group may have advantages for the patient and the surgeon, i.e. less pain, early recovery and magnified views. As we have technically shown it to be possible, perhaps laparoscopic approaches should be discussed if the teams in these centres are of advanced laparoscopic surgeons working in multi-skilled groups.

Robotic laparoscopic surgery: cost and training

The advantages of minimally invasive surgery are well accepted. Shorter hospital stays, decreased postoperative pain, rapid return to preoperative activity, decreased postoperative ileus, and preserved immune function are among the benefits of the laparoscopic approach. However, the instruments of laparoscopy afford surgeons limited precision and poor ergonomics, and their use is associated with a significant learning curve and the amount of time and energy necessary to develop and maintain such advanced laparoscopic skills is not insignificant. The robotic surgery allows all laparoscopists to perform advanced laparoscopic procedures with greater ease. The potential advantages of surgical robotic systems include making advanced laparoscopic surgical procedures accessible to surgeons who do not have advanced video endoscopic training and broadening the scope of surgical procedures that can be performed using the laparoscopic method. The wristed instruments, x10 magnifications, tremor filtering, scaling of movements and three-dimensional view allow the urologist to perform the intricate dissection and anastomosis with high precision. The robot is not, however, without significant disadvantages as compared with traditional laparoscopy. These include greater expense and consumption of operating room resources such as space and the availability of skilled technical staff, complete elimination of tactile feedback, and more limited options for trocar placement. The current cost of the da Vinci system is $ 1.2 million and annual maintenance is $ 138000. Many studies suggest that depreciation and maintenance costs can be minimised if the number of robotic cases is increased. The high cost of purchasing and maintaining the instruments of the robotic system is one of its many disadvantages. The availability of the robotic systems to only a limited number of centres reduces surgical training opportunities. Hospital administrators and surgeons must define the reasons for developing a robotic surgical program: it is very important to show that robotics will add a dimension that will benefit the hospital, the patient care and institutional recognition. Another essential task to overcome is the important education of the operating room nursing staff, a significant difference between this modality and traditional surgery. Without operating room environment support, most surgeons will revert to traditional methods even after a few successful robotics cases. As the field of robotic surgery continues to grow, graduate medical education and continuing medical education programs that address the surgical robotic learning needs of residents and practicing surgeons need to be developed.

Robotic Oncological Surgery: Technology That's Here to Stay?

A robot functioning in an environment may exhibit various forms of behavior emerge from the interaction with its environment through sense, control and plan activities. Hence, this paper introduces a behaviour selection based navigation and obstacle avoidance algorithm with effective method for adapting robotic behavior according to the environment conditions and the navigated terrain. The developed algorithm enable the robot to select the suitable behavior in real-time to avoid obstacles based on sensory information through visual and ultrasonic sensors utilizing the robot's ability to step over obstacles, and move between surfaces of different heights. In addition, it allows the robot to react in appropriate manner to the changing conditions either by fine-tuning of behaviors or by selecting different set of behaviors to increase the efficiency of the robot over time. The presented approach has been demonstrated on quadruped robot in several different experimental environments and the paper provides an analysis of its performance.

Quantitative characterization of viscoelastic properties of human prostate correlated with histology

Quantification of mechanical properties of human prostate tissue is important for developing sonoelastography for prostate cancer detection. In this study, we characterized the frequency-dependent complex Young's modulus of normal and cancerous prostate tissues in vitro by using stress relaxation testing and viscoelastic tissue modeling methods. After radical prostatectomy, small cylindrical tissue samples were acquired in the posterior region of each prostate. A total of 17 samples from eight human prostates were obtained and tested. Stress relaxation tests on prostate samples produced repeatable results that fit a viscoelastic Kelvin-Voigt fractional derivative (KVFD) model (r(2)>0.97). For normal (n = 8) and cancerous (n = 9) prostate samples, the average magnitudes of the complex Young's moduli (|E*|) were 15.9 +/- 5.9 kPa and 40.4 +/- 15.7 kPa at 150 Hz, respectively, giving an elastic contrast of 2.6:1. Nine two-sample t-tests indicated that there are significant differences between stiffness of normal and cancerous prostate tissues in the same gland (p < 0.01). This study contributes to the current limited knowledge on the viscoelastic properties of the human prostate, and the inherent elastic contrast produced by cancer.

Factors associated with ureteral burn injury from an electrified guidewire

PURPOSE

During ureteroscopic procedures, electrocautery is often utilized in the presence of an intra-ureteral guidewire. Inadvertent electrification of the guidewire may occur if the active electrode comes into contact with the guidewire, potentially resulting in a ureteral burn injury. This study investigates under what conditions electrification of a ureteral guidewire would result in ureteral burn injury.

MATERIALS AND METHODS

Porcine kidney/ureter units were tested in a saline bath using a guidewire within the ureter. The collecting system was filled with either saline or water and the guidewire was electrified with varying power and mode settings. The contact area between the wire and ureter was adjusted to 1/2 or 1/4 of the total ureteral length. The ureters were then inspected for evidence of burn injury microscopically by a pathologist in a blinded fashion.

RESULTS

Ten kidney/ureter units were tested. Four units were filled with saline and none of these demonstrated any burn injury. Six kidney/ureter units were filled with water prior to electrification of the wire. Small amounts of burned tissue were noted in those with the full length of the ureter exposed. Moderate to severe burning was present in those with 1/2 of the ureter exposed. Ureters exposed to 120-W cutting current had more injury than those exposed to 80-W coagulation current.

CONCLUSIONS

Inadvertent electrification of a ureteral guidewire does not necessarily result in ureteral burn injury. The presence and extent of ureteral injury depends primarily on the irrigating fluid used, as well as the amount of ureter exposed to the electrified guidewire.

Surgical case order does not affect outcomes during robot-assisted radical prostatectomy

Fatigue has been implicated in medical errors. There has not been any report in the surgical literature addressing the impact of case order on patient outcomes. The purpose of this study was to determine whether the order of robot-assisted radical prostatectomy (RARP) has an influence on surgical outcomes. All patients undergoing RARP by a single surgeon (J.V.J.) on days during which there were three consecutive RARP cases were divided into three groups based on case order. They were compared with respect to pre-operative, intra-operative, and post-operative parameters. Complications were classified as surgical (bladder neck contracture, urinary tract infection, post-operative bleeding) or medical (deep venous thrombosis, myocardial infarction, C. difficile colitis) and compared between the groups. A total of 381 patients were evaluated, 127 in each group. The median start time for group 1 was 0732 hours (range 0722-0900 hours), group 2 was 1108 hours (range 1008-1344 hours), and group 3 was 1458 hours (range 1258-1742 hours). Patient age, body mass index, pre-operative PSA, pre-operative Gleason score, and clinical stage were all similar amongst the groups. The total operative time was equivalent, as was the estimated blood loss. Prostate volume and pathologic Gleason score showed no significant changes between groups. Pathologic stage showed a slight trend toward increasing percentages of T3 disease with increasing group number (group 1 = 17%, group 2 = 19%, and group 3 = 24%). Positive margin rates were lowest in group 3 (11.8% for group 1, 12.6% for group 2, and 3.9% for group 3). Complication rates were equivalent at 5-7% overall (2-6% surgical complications, 2-4% medical). Three patients from each group had PSA recurrence. With an experienced surgical team, three RARP procedures may be performed in 1 day without significant variation in surgical outcomes among the cases.