Intraoperative photodynamic evaluation of surgical margins during endoscopic extraperitoneal radical prostatectomy with the use of 5-aminolevulinic acid

Fluorescence imaging analysis of distribution of indocyanine green in molecular and nanoform in tumor model

BACKGROUND

The efficient intraoperative identification of tumors requires the development of highly specific near-infrared (NIR) probes as contrast agents. One of the most effective dyes existing in clinic oncology is Indocyanine Green (ICG). However, ICG has a rapid excretion, thus ruling out its extended accumulation in pathological tissues therefore limiting its clinical applications. ICG colloid solution (ICG NPs) consists predominantly of J-aggregates and to a lesser extent of H-aggregates and monomers. In the present study we assessed the spectral properties of ICG nanoforms in preclinical models.

METHODS

We used optical spectroscopy and video fluorescence navigation to monitor accumulation and distribution of ICG monomers and ICG NPs in various tissues in mice with xenografted laryngopharyngeal carcinoma after intravenous drugs injection.

RESULTS

After i.v. injection, the molecular form of ICG was not retained in the tumor and its circulation cycle averaged 5 min. Alternatively, the nanoform of the drug had a different pharmacokinetics, reaching maximum accumulation 24 h after intravenous injection. Moreover, once in the circulation, we observed a progressive accumulation in the tumor of both ICG H-aggregates and ICG monomers, but not J-aggregates.

CONCLUSION

Spectral characteristics of ICG NPs indicated the presence of several fractions, namely, J- and H-aggregates along with molecular forms. These fractions had different fluorescence spectra, allowing us to track the transformation of the drug in vivo conditions. After ICG NPs administration, J-aggregates induce accumulation of monomeric forms in the tumor, enabling extended intraoperative diagnostic, and as such further studies of J-aggregates for theranostic applications in oncological surgery are of great interest.

Emerging Intraoperative Imaging Technologies in Urologic Oncology

As surgical cases become more complex, intraoperative imaging is increasingly being used. This article discusses emerging imaging technologies used in prostate, kidney, and bladder cancer surgery, including ultrasound, fluorescence-based, and enhanced endoscopy techniques including their strengths and limitations.

The evolution of image guidance in robotic-assisted laparoscopic prostatectomy (RALP): a glimpse into the future

OBJECTIVES

To describe the innovative intraoperative technologies emerging to aid surgeons during minimally invasive robotic-assisted laparoscopic prostatectomy.

METHODS

We searched multiple electronic databases reporting on intraoperative imaging and navigation technologies, robotic surgery in combination with 3D modeling and 3D printing used during laparoscopic or robotic-assisted laparoscopic prostatectomy. Additional searches were conducted for articles that considered the role of artificial intelligence and machine learning and their application to robotic surgery. We excluded studies using intraoperative navigation technologies during open radical prostatectomy and studies considering technology to visualize lymph nodes. Intraoperative imaging using either transrectal ultrasonography or augmented reality was associated with a potential decrease in positive surgical margins rates. Improvements in detecting capsular involvement may be seen with augmented reality. The benefit, feasibility and applications of other imaging modalities such as 3D-printed models and optical imaging are discussed.

CONCLUSION

The application of image-guided surgery and robotics has led to the development of promising new intraoperative imaging technologies such as augmented reality, fluorescence imaging, optical coherence tomography, confocal laser endomicroscopy and 3D printing. Currently challenges regarding tissue deformation and automatic tracking of prostate movements remain and there is a paucity in the literature supporting the use of these technologies. Urologic surgeons are encouraged to improve and test these advanced technologies in the clinical arena, preferably with comparative, randomized, trials.

Photodynamic diagnosis and therapy for urothelial carcinoma and prostate cancer: new imaging technology and therapy

Photodynamic technology using light-sensitive and fluorescent substances has an important role in an accurate diagnosis for a variety of malignancies, including bladder cancer and prostate cancer. Light-sensitive and fluorescent substances accumulate specifically in tumor cells compared to normal tissue, and by light irradiation and excitation at each specific wavelength, tumor lesion, blood flow, lymph node and so on show fluorescence. 5-Aminolevulinic acid (ALA) is converted to protoporphyrin IX (PpIX) into mitochondria. PpIX is excited by blue light, red fluorescence is emitted in the mitochondria. This phenomenon is the mechanism of ALA-mediated photodynamic diagnosis (ALA-PDD). ALA-PDD has made it possible to visualize smaller lesions and flat lesions that were previously difficult to visualize by endoscope using a white-light source. So accurate diagnosis and complete resection become possible during operation. The accumulation of PpIX in the mitochondria also induces direct mitochondrial damage and subsequent cell death by red and green light. This biological reaction is the ALA-mediate photodynamic therapy (ALA-PDT). ALA-PDT has been developed as a modality for minimum invasive cancer treatment that utilizes low-energy light and photosensitizer. Vascular-activated photosensitizer induces rapid tumor ablation by PDT involving direct tumor cell killing as well as damage to the exposed microvasculature. We summarize the clinical outcomes of PDD and PDT for urothelial carcinoma and prostate cancer.

"Real-time" Assessment of Surgical Margins During Radical Prostatectomy: State-of-the-Art

Histopathologic examination of the pathologic specimens using hematoxylin & eosin stains represents the backbone of the modern pathology. It is time-consuming; thus, "real-time" assessment of prostatic and periprostatic tissue has gained special interest in the diagnosis and management of prostate cancer. The current study focuses on the review of the different available techniques for "real-time" evaluation of surgical margins during radical prostatectomy (RP). We performed a comprehensive search of the Medline database to identify all the articles discussing "real-time" or intraoperative assessment of surgical margins during RP. Several filters were applied to the search to include only English articles performed on human subjects and published between January 2000 and March 2019. The search revealed several options for pathologic assessment of surgical margins including intraoperative frozen sections, confocal laser endomicroscopy, optical spectroscopy, photodynamic diagnosis, optical coherence tomography, multiphoton microscopy, structured illumination microscopy, 3D augmented reality, and ex vivo fluorescence confocal microscope. Frozen section represents the gold standard technique for real-time pathologic examinations of surgical margins during RP; however, several other options showed promising results in the initial clinical trials, and considering the rapid development in the field of molecular and cellular imaging, some of these options may serve as an alternative to frozen section.

Precision prostate cancer surgery: an overview of new technologies and techniques

Over the past few years several new technologies have become available for the management of PCa. The implementation of robotic surgery allowed an unprecedented refinement of surgical techniques, and the RARP procedure is constantly evolving. Nowadays research is mainly focused towards a "tailored" case-specific surgical approach that might allow to achieve PCa control while preserving urinary continence and erectile function. Therefore, in contemporary urology era, several new tools have been introduced to optimize surgical planning, to aid surgical navigation, and to refine surgical execution. In this non-systematic review emerges that a better imaging technique in the preoperative setting can facilitate surgical planning. Moreover, in the intraoperative setting, new tools for image-guided surgical navigation are promising and will allow real time understanding of surgical anatomy. In the next future, a more personalized approach for the minimally invasive surgical treatment of PCa will be available, and the achievement of the best oncological and functional outcomes will be obtained.

Novel methods for mapping the cavernous nerves during radical prostatectomy

The cavernous nerves, which course along the surface of the prostate gland, are responsible for erectile function. During radical prostatectomy, urologists are challenged in preserving these nerves and their function. Cavernous nerves are microscopic and show variable location in different patients; therefore, postoperative sexual potency rates are widely variable following radical prostatectomy. A variety of technologies, including electrical and optical nerve stimulation, dye-based optical fluorescence and microscopy, spectroscopy, ultrasound and magnetic resonance imaging have all been used to study cavernous nerve anatomy and physiology, and some of these methods are also potential intraoperative methods for identifying and preserving cavernous nerves. However, all of these technologies have inherent limitations, including slow or inconsistent nerve responses, poor image resolution, shallow image depth, slow image acquisition times and/or safety concerns. New and emerging technologies, as well as multimodal approaches combining existing methods, hold promise for improved postoperative sexual outcomes and patient quality of life following radical prostatectomy.

Performance of 5-aminolevulinic-acid-based photodynamic diagnosis for radical prostatectomy

Background

The aim of this study was to investigate whether we could detect positive surgical margins during open and laparoscopic radical prostatectomy by 5-aminolevulinic acid (ALA) photodynamic diagnosis (PDD) and mapping of red fluorescence in human prostate cancer cells.

Methods

All 52 patients were diagnosed with prostate cancer by biopsy. They had a positive core in the apex or highly suspicious positive margins. Open and laparoscopic radical prostatectomy was performed in 18 and 34 cases, respectively. One gram of ALA solution was given intraoperatively, orally through a stomach tube. An endoscopic PDD system, including a D-Light C, CCU Tricam SLII/3CCD CH Tricam-P PDD, and HOPKINS II Straight Forward Telescope 0°, was used. The D-Light C light source was equipped with a band-pass filter. The CCU Tricam SLII/3CCD CHTricam-P PDD video camera system was equipped with a long-pass filter. The laparoscopy optic component was equipped with a yellow long-pass filter.

Results

One of the 52 patients had a red-fluorescent-positive margin of the excised whole prostate and the positive surgical margin was histologically confirmed. In the section of excised prostate, we obtained 141 biopsied samples. The sensitivity and specificity were 75.0 % and 87.3 %, respectively.

Conclusions

Intraoperative ALA-PDD is feasible. However, heat degeneration and length of positive surgical margin have crucial influences on red fluorescence. In future, a randomized clinical trial should be carried out.

Application of 5-aminolevulinic acid-mediated photodynamic diagnosis to robot-assisted laparoscopic radical prostatectomy

OBJECTIVE

To determine the appropriate resection margin, we performed photodynamic diagnosis (PDD) mediated by 5-aminolevulinic acid (ALA; ALA-PDD) during robot-assisted laparoscopic radical prostatectomy (RALP).

MATERIALS AND METHODS

We performed ALA-PDD during RALP using da Vinci S Surgical System in 6 patients. The function of TilePro multi-image stereo-viewer enables simultaneous 2-tiered display of the real surgical field by the da Vinci S Surgical System and the ALA-PDD endoscopic system in surgeon console. The resection margins of prostate were biopsied under the observation of ALA-PDD and assessed pathologically.

RESULTS

The process of ALA-PDD during RALP was proceeded favorably in all the 6 patients. All 22 biopsy specimens obtained from resection margin of prostate demonstrated fluorescence-negative inside the body and also pathologically confirmed negative findings in malignancy. Moreover, no perioperative complications were observed through all procedures of ALA-PDD in all the 6 patients.

CONCLUSION

We presented particularly that application of ALA-PDD during RALP, as a novel and practical technique for decision of the correct resection margin.

Intraoperative optical imaging and tissue interrogation during urologic surgery

PURPOSE OF REVIEW

To review optical imaging technologies in urologic surgery aimed to facilitate intraoperative imaging and tissue interrogation.

RECENT FINDINGS

Emerging new optical imaging technologies can be integrated in the operating room environment during minimally invasive and open surgery. These technologies include macroscopic fluorescence imaging that provides contrast enhancement between normal and diseased tissue and microscopic imaging that provides tissue characterization.

SUMMARY

Optical imaging technologies that have reached the clinical arena in urologic surgery were reviewed, including photodynamic diagnosis, near infrared fluorescence imaging, optical coherence tomography, and confocal laser endomicroscopy.

Fluorescence imaging in surgery

Although the modern surgical era is highlighted by multiple technological advances and innovations, one area that has remained constant is the dependence of the surgeon's vision on white-light reflectance. This renders different body tissues in a limited palette of various shades of pink and red, thereby limiting the visual contrast available to the operating surgeon. Healthy tissue, anatomic variations, and diseased states are seen as slight discolorations relative to each other and differences are inherently limited in dynamic range. In the upcoming years, surgery will undergo a paradigm shift with the use of targeted fluorescence imaging probes aimed at augmenting the surgical armamentarium by expanding the "visible" spectrum available to surgeons. Such fluorescent "smart probes" will provide real-time, intraoperative, pseudo-color, high-contrast delineation of both normal and pathologic tissues. Fluorescent surgical molecular guidance promises another major leap forward to improve patient safety and clinical outcomes, and to reduce overall healthcare costs. This review provides an overview of current and future surgical applications of fluorescence imaging in diseased and nondiseased tissues and focus on the innovative fields of image processing and instrumentation.

Use of the dietary supplement 5-aminiolevulinic acid (5-ALA) and its relationship with glucose levels and hemoglobin A1C among individuals with prediabetes

OBJECTIVE

This study examined the association between 5-aminolevulinic acid (5-ALA) and glucose tolerance.

DESIGN

A double blinded, randomized prospective parallel-group comparison study.

SETTING

Participants were recruited from the community in Honolulu, Hawaii, using radio and TV ads, and at community events.

PARTICIPANTS

One hundred fifty-four males and females ages 40-70 years, with evidence of prediabetes: hemoglobin A1c (HbA1c) 5.8%-7.0% at the screening visit.

INTERVENTION

Participants were randomized equally to one of three study groups: (1) low dose 5-ALA supplement (15 mg capsule); (2) high dose 5-ALA (50 mg capsule); and (3) control (placebo capsule of identical size and color).

MAIN OUTCOME MEASURES

HbA1c and 2 hours post-oral glucose tolerance test (OGTT) glucose levels.

RESULTS

Among individuals taking 5-ALA supplements for 12 weeks, 2 hours post-OGTT glucose levels declined significantly compared to those not taking the supplement (p= 0.02). The relationships were stronger among those with baseline glucose intolerance, or 2 hours post-OGTT glucose measurements greater than 140 mg/dL (p= 0.005 and p= 0.02 for the low and high dose group, respectively). Similar trends were observed for HbA1c but results were of borderline significance (p= 0.07). No untoward effects were reported.

CONCLUSIONS

Further studies are indicated. The potential benefits of 5-ALA dietary supplementation are affirmed by this investigation.

Fluorescence guidance in urologic surgery

PURPOSE OF REVIEW

Fluorescent tracers can provide anatomical and functional information without altering the visual surgical field. Despite the advances that are being made in tracer development, only a few fluorescent tracers are available for urological interventions.

RECENT FINDINGS

Protoporphyrin IX, hypericin, fluorescein, and indocyanine green were shown to facilitate surgical resection in various ways. Hybrid imaging agents, combining radio and fluorescent labels, have shown improved integration between preoperative and intraoperative imaging. With the rise of surgical fluorescence guidance, various camera systems have been developed that are tailored for optimal detection of the fluorochromes of interest.

SUMMARY

In this review, the basics of fluorescence-guided surgery, including tracer and hardware requirements are discussed.

Hemodynamic effects of orally administered delta-ALA during radical prostatectomy

PURPOSE

We investigated hemodynamics in patients receiving delta-Aminolevulinic acid (delta-ALA) to visualize tumor margins prior to radical retro pubic prostatectomy.

PATIENTS

Twenty patients undergoing elective open radical retro pubic prostatectomy (RRP).

METHODS

Cohort observational study. Ten patients receiving 20 mg/kg of delta-ALA orally prior to surgery (delta-ALA) and 10 patients undergoing RRP without the application of delta-ALA served as a retrospectively matched cohort (CONTROL).

MEASUREMENTS

Changes in heart rate (HR), mean arterial blood pressure (MAP), and functional hemodynamic parameters were assessed by electrocardiogram, non-invasive and invasive blood pressure monitoring plus transcardiopulmonary thermodilution.

RESULTS

Patients of both groups did not differ in means of age, body mass index, or ASA classification. During surgery, HR and MAP did not differ significantly between both groups. Also, the amount of IV crystalloids and colloids did not differ significantly. In contrast, the amount of vasopressor necessary to maintain MAP within the target range of 70-90 mmHg was significantly higher in delta-ALA when compared to CONTROL (0.08 ± 0.04 μg/kg/min (delta-ALA) vs. 0.03 ± 0.02 μg/kg/min (CONTROL); P < 0.01). Immediately after surgery, patients of delta-ALA showed a significantly higher heart rate (82 ± 18 min(-1) vs. 67 ± 9 min(-1); P < 0.05) compared to patients of CONTROL. Cardiac index, global end-diastolic volume index, and extravascular lung water index were significantly higher after surgery, when compared to baseline values (P < 0.05).

CONCLUSIONS

Orally administered delta-ALA prior to open radical prostatectomy induces hemodynamic instability in the perioperative period requiring vasopressor support. Further, an increase of extravascular lung water points toward an increased vascular permeability induced by delta-ALA.

Photodynamic diagnosis of positive margin during radical prostatectomy: preliminary experience with 5-aminolevulinic acid

OBJECTIVES

To investigate the feasibility of intraoperative photodynamic diagnosis (PDD) by 5-aminolevulinic acid (ALA) for the identification of positive surgical margins (PSM) during retropubic radical prostatectomy (RRP) in patients with prostate cancer (PCa).

METHODS

Intraoperative PDD was carried out in 16 patients with pathologically confirmed PCa by biopsy of the apex, or carrying >25% of probability of extraprostatic extension as defined by Japan PC Table. Before operation, 1.0 g of ALA was given orally. During open RRP, the resection margins inside the body were examined by PDD system with a fluorescence laparoscope. After their removal, 12 harvested prostates were divided and also investigated by PDD. Red fluorescent-positive lesions were biopsied and compared with the pathological result.

RESULTS

All 16 patients were fluorescence-negative inside the body, and negative margins were pathologically confirmed during PDD. Among the 43 specimens of 12 cases obtained by biopsy under PDD, 11 specimens (25.6%) were pathologically diagnosed as malignant tissue (adenocarcinoma, 10 specimens; high grade prostatic intraepithelial neoplasia, 1 specimen) and 19 specimens (44.2%) were evaluated as positive fluorescence by PDD with a sensitivity of 81.8%, a specificity of 68.8% and a predictive accuracy of 72.1%. No side-effects were observed and the procedures were well tolerated.

CONCLUSIONS

PDD mediated by ALA during RRP might be a feasible and safe modality for detection of surgical margins. Further prospective randomized studies with larger populations are required.

Intraoperative photodynamic detection of normal parathyroid glands using 5-aminolevulinic acid

OBJECTIVE

It is important to identify and save the normal parathyroid glands during head and neck surgery because of their role in regulating the blood calcium level, yet it is often difficult to localize normal parathyroid glands during surgery. Fluorescence-guided parathyroidectomy in patients with hyperparathyroidism has already proved useful. However, there are few reports of fluorescence-guided localization of normal parathyroid glands in humans. We investigated the utility of fluorescence-guided localization of normal parathyroid glands during thyroidectomy and completed a spectral fluorescence analysis of the accumulation of 5-aminolevulinic acid metabolites in the parathyroid glands.

METHODS

Eight patients with benign thyroid disease and five with malignant thyroid tumors were given 20 mg/kg body weight of 5-aminolevulinic acid orally 5 hours before surgery. After the posterior surface of the thyroid gland was exposed and the recurrent laryngeal nerve was identified, we illuminated the area with a violet-blue light of 405 nm. Tissues showing red fluorescence were biopsied to analyze the spectral fluorescence.

RESULTS

Under the violet-blue light, normal parathyroid glands showed red fluorescence, while the surrounding structures such as the thyroid gland, muscles, and fat remained nonfluorescent. The spectral peak was observed at 635 nm indicating 5-aminolevulinic acid metabolites. Histopathologically, the biopsied tissue corresponded to normal parathyroid glands.

CONCLUSIONS

5-Aminolevulinic acid is useful to localize the normal parathyroid glands during thyroid surgery in humans.