Delta-Aminolevulinic Acid-Mediated Photodiagnoses in Surgical Oncology: A Historical Review of Clinical Trials.

Fluorescence imaging is an emerging clinical technique for real-time intraoperative visualization of tumors and their boundaries. Though multiple fluorescent contrast agents are available in the basic sciences, few fluorescence agents are available for clinical use. Of the clinical fluorophores, delta aminolevulinic acid (5ALA) is unique for generating visible wavelength tumor-specific fluorescence. In 2017, 5ALA was FDA-approved for glioma surgery in the United States. Additionally, clinical studies suggest this agent may have utility in surgical subspecialties outside of neurosurgery. Data from dermatology, OB/GYN, urology, cardiothoracic surgery, and gastrointestinal surgery show 5ALA is helpful for intraoperative visualization of malignant tissues in multiple organ systems. This review summarizes data from English-language 5ALA clinical trials across surgical subspecialties. Imaging systems, routes of administration, dosing, efficacy, and related side effects are reviewed. We found that modified surgical microscopes and endoscopes are the preferred imaging devices. Systemic dosing across surgical specialties range between 5 and 30 mg/kg bodyweight. Multiple studies discussed potential for skin irritation with sun exposure, however this side effect is infrequently reported. Overall, 5ALA has shown high sensitivity for labeling malignant tissues and providing a means to visualize malignant tissue not apparent with standard operative light sources

New Options for Non-invasive Imaging and Non-invasive Treatment of Skin Cancers

Tausta Tyvisolusyöpä on maailman yleisin syöpä. Tyvisolusyövällä on eri alatyyppejä, joista pinnallinen tyvisolusyöpä ja ohut nodulaarinen tyvisolusyöpä ovat vähäisen riskin tyyppejä, jotka on mahdollista hoitaa muutoin kuin leikkaamalla. Pinnallinen tyvisolusyöpä on lisääntynyt muita alatyyppejä nopeammin, ja näin ollen myös ei-kirurgisten hoitovaihtoehtojen käyttö todennäköisesti lisääntyy. Valoaktivaatiohoito ja voidehoidot, joita ovat imikimodi ja 5-fluorourasiili, ovat vaihtoehtoja kirurgialle. Valoaktivaatiohoidon etuja ovat erinomainen kosmeettinen lopputulos sekä lyhytkestoisempi hoitoaika ja paikallisreaktion kesto verrattuna voidehoitoihin. Imikimodin teho on kuitenkin parempi kuin valoaktivaatiohoidon. Suuren riskin tyvisolusyöpiä ovat aggressiiviset alatyypit, joille tyypillisiä ovat kasvaimen epätarkkarajaisuus ja kliinisesti näkymättömät kasvainalueet. Lentigo maligna -melanooma on ihomelanooman alamuoto, jolle tyypillisiä ovat myös nämä piirteet. Lentigo maligna on lentigo maligna -melanooman esiastemuoto. Näitä kahta on vaikea erottaa toisistaan silmin ja dermatoskoopilla arvioiden. Epätarkkarajaiset ihosyövät ovat siis kliininen haaste. Kajoamattomilla kuvantamismenetelmillä on mahdollista parantaa ihokasvainten diagnostiikkaa ja arviota. Hyperspektrikuvantaminen on uusi, nopea ja tietokoneavusteinen kuvantamismenetelmä, jolla on laaja kuvausalue. Tavoitteet Väitöskirjassa tutkitaan hyperspektrikuvantamista ja vähäisen riskin tyvisolusyövän valoaktivaatiohoitoa kliinisessä lääketutkimuksessa. Tavoitteena on tutkia hyperspektrikameran kykyä erottaa lentigo maligna -melanooma ja lentigo maligna toisistaan, sekä arvioida hyperspektrikameran kykyä määrittää epätarkkarajaisen tyvisolusyövän rajat ennen leikkausta verrattuna kliiniseen arvioon dermatoskoopin kanssa. Kliinisen lääketutkimuksen tavoitteena on verrata kolmen eri valoherkistäjävoiteen tehoa vähäisen riskin tyvisolusyövän valoaktivaatiohoidossa. Menetelmät Hyperspektrikuvantamista tutkittiin kahdessa pilottitutkimuksessa. Näistä toisessa kuvattiin lentigo malignaa/lentigo maligna –melanoomaa, ja toisessa epätarkkarajaista tyvisolusyöpää. Molemmissa tutkimuksissa kasvaimet arvioitiin ennen kuvantamista kliinisesti dermatoskoopin avulla. Lopuksi kasvaimet leikattiin. Hyperspektrikuvat tuotettiin matemaattisen mallinnuksen avulla tietokoneavusteisesti. Patologi, joka arvioi leikkeet, ei tiennyt, mitä hyperspektrilöydökset olivat. Kameran löydöksiä verrattiin histopatologiaan, ja epätarkkarajaisen tyvisolusyövän tapauksessa myös kliinisesti määritettyihin kasvaimen rajoihin. Kliininen lääketutkimus oli tutkijalähtöinen, prospektiivinen, kontrolloitu, satunnaistettu ja kaksoissokkoutettu. Tutkimuksessa verrattiin kahden uudehkon valoherkistäjävoiteen eli 5-aminolevuliinihapon nanoemulsion ja matalapitoisen heksyyliaminolevulinaatin tehoa laajasti käytettyyn metyyliaminolevulinaattiin. Päätulos oli histologinen paraneminen kolme kuukautta valoaktivaatiohoidon jälkeen. Toissijaisia tuloksia olivat kosmeettinen lopputulos sekä hoidon haittavaikutukset eli kipu ja hoidonjälkeinen paikallisreaktio. Kivunhoitona käytettiin pitkävaikutteista paikallispuudutetta ennen kasvainten käsittelyä valoaktivaatiohoitoa varten. Tutkimuksessa arvioitiin myös valoherkistäjävoiteen fluoresenssia ja kulumista valotuksen aikana (ns. photobleaching) kokeellisella laitteistolla. Diagnoosi ja hoitotulos varmistettiin koepaloin. Tutkimuksessa potilaat ja tulosten arvioijat eivät tienneet, mitä valoherkistäjää oli käytetty. Tulokset Lentigo maligna -melanooman, lentigo malignan ja terveen ihon hyperspektrikäyrät ovat erilaisia. Näin ollen lentigo maligna -melanooma ja lentigo maligna on mahdollista erottaa toisistaan hyperspektrikuvantamisen avulla. Hyperspektrikuvien perusteella oli myös mahdollista paikallistaa invaasioalue. Hyperspektrikamera määritti epätarkkarajaisen tyvisolusyövän rajat tarkemmin kuin kliinisesti oli määritetty, ja histopatologia tuki tätä löydöstä. Valoaktivaatiohoidossa tyvisolusyöpä parani lähes yhtä hyvin matalapitoisella heksyyliaminolevulinaatilla kuin korkeapitoisemmilla 5-aminolevuliinihapon nanoemulsiolla ja metyyliaminolevulinaatilla. Valoherkistäjävoiteiden välillä ei ollut eroja haittavaikutuksissa tai kosmeettisessa lopputuloksessa. Fluoresenssin ja valoherkistäjän kulumisen tuloksissa oli laaja hajonta. Johtopäätökset Hyperspektrikuvantaminen vaikuttaa lupaavalta uudelta menetelmältä, jolla on laaja kuvausalue, ja joka on nopea ja helppokäyttöinen. Lisäksi hyperspektrikamera näyttää pystyvän visualisoimaan silmälle näkymättömiä muutoksia. Heksyyliaminolevulinaatti on mielenkiintoinen uusi vaihtoehto vähäisen riskin tyvisolusyövän valoaktivaatiohoitoon, sillä jo matalalla pitoisuudella saavutetaan vastaava hoitotulos kuin korkeammilla pitoisuuksilla 5- aminolevuliinihapon nanoemulsiota tai metyyliaminolevulinaattia. Kuitenkaan hoidon kosmeettisessa lopputuloksessa tai haittavaikutuksissa ei ole eroja valoherkistäjien välillä.Background Basal cell carcinoma is the most common cancer in the world. The incidence of superficial basal cell carcinoma, a subtype of basal cell carcinoma, is rising at a far steeper rate than the other subtypes, and as a non-aggressive subtype, it can be treated non-invasively. Aggressive subtypes of basal cell carcinoma are often ill-defined, which poses a clinical problem in preoperative margin assessment. Another ill-defined skin cancer type is lentigo maligna. Lentigo maligna is an in situ melanoma, and a precursor of lentigo maligna melanoma. These two forms are clinically challenging to distinguish from each other, which is crucial as melanoma has the worst prognosis of all skin cancers. Non-invasive imaging is an option for increasing the accuracy of preoperative diagnosis and the assessment. Hyperspectral imaging is a novel, fast, and computer-aided imaging modality with a wide field of view. In non-invasive treatment of non-aggressive basal cell carcinomas, photodynamic therapy has many advantages: an excellent cosmetic outcome as well as a shorter application time and recovery period. Notwithstanding these advantages, the efficacy of photodynamic therapy is lower when compared to topical pharmacological options such as imiquimod and 5- fluorouracil. Objectives This dissertation focuses on non-invasive imaging and non-invasive treatment. In non-invasive imaging, the aim is to study the performance of a hyperspectral imaging system in separating lentigo maligna melanoma from lentigo maligna and assessing the preoperative margins of ill-defined basal cell carcinomas compared to clinical delineation assessments performed with a dermoscope. In non-invasive treatment, the aim is to compare the efficacy of three different photosensitisers in photodynamic therapy of non-aggressive basal cell carcinomas. Methods There are two pilot studies with hyperspectral imaging: one on lentigo maligna and lentigo maligna melanoma, and another one on ill-defined basal cell carcinoma. Tumours were preoperatively visually inspected utilising a dermoscope, and thereafter imaged with the hyperspectral imaging system. Next, surgical excision was performed. Hyperspectral images were created with computer-aided mathematical models. Additional mathematical models were subsequently developed. In the results analysis, the findings of the hyperspectral imaging and clinically assessed margins were compared to the histopathology results, where assessment was performed blind to the hyperspectral imaging findings. A non-sponsored, prospective, randomised, controlled and double-blinded trial focused on non-invasive treatment. In this trial, two novel photosensitisers, 5- aminolevulinic acid nanoemulsion and low-concentration hexylaminolevulinate, were compared to the commonly used methylaminolevulinate in photodynamic therapy of non-aggressive basal cell carcinomas, i.e. thin nodular or superficial subtypes. The primary outcome was histological clearance at three months. Secondary outcomes included adverse events such as pain associated with the treatment while using a long-lasting local anaesthetic as pain management, post- treatment reaction, as well as cosmetic outcome, and fluorescence and photobleaching during the illumination. We used an experimental fluorescence imaging system. Punch biopsies were performed prior to treatment and during follow-up. Both patient and observers of outcomes were blind to the photosensitiser that was used. Results Hyperspectral imaging exhibited a unique hyperspectral graph for lentigo maligna melanoma, lentigo maligna, and healthy skin. Based on these results, hyperspectral images were created where hyperspectral data was represented in several abundance maps. The maps showed differing abundances for lentigo maligna melanoma and lentigo maligna, and it was possible to localise the invasion site inside the lesion. For ill-defined basal cell carcinoma, the margins of the tumour were delineated more accurately than by clinical assessment, and the results were confirmed with histopathology. The results of the clinical trial in photodynamic therapy showed that the histological clearance of hexylaminolevulinate was similar compared to 5- aminolevulinic acid nanoemulsion and methylaminolevulinate, with no differences in cosmetic outcome, pain or post-treatment reaction between the arms. In our fluorescence and photobleaching analyses the results were widely spread. Conclusions In conclusion, hyperspectral imaging seems to be a promising and useful new imaging modality with a wide field of view: it is fast, easy to use and it seems to be capable of visualising subclinical findings. In non-invasive treatment, hexylaminolevulinate is an interesting option for photodynamic therapy of non- aggressive basal cell carcinomas. Hexylaminolevulinate at low concentrations achieves a comparable efficacy to 5-aminolevulinic acid nanoemulsion and methylaminolevulinate at higher concentrations. No differences were observed in adverse events or cosmetic outcome between the arms

Digital Assessment of Facial Acne Vulgaris

Acne is chronic disorder of the pilosebaceous units with excess sebum production, follicular epidermal hyperproliferation, inflammation and Propionibacterium acnes (P acnes) activity. Dermatologists use manual methods such as direct visual assessment and ordinary flash photography to assess the acne. However, these manual methods are very time consuming and may result in intra-observer and inter-observer variations, even by experienced dermatologists. To address these issues, there have been a number of research conducted using computational imaging methods for aiding in the acne diagnosis but they fail while solving more complex classification problems, cannot be used for real-time analysis, are semi-automated methods and they lack flexibilit

Recent Advances and the Potential for Clinical Use of Autofluorescence Detection of Extra-Ophthalmic Tissues

The autofluorescence (AF) characteristics of endogenous fluorophores allow the label-free assessment and visualization of cells and tissues of the human body. While AF imaging (AFI) is well-established in ophthalmology, its clinical applications are steadily expanding to other disciplines. This review summarizes clinical advances of AF techniques published during the past decade. A systematic search of the MEDLINE database and Cochrane Library databases was performed to identify clinical AF studies in extra-ophthalmic tissues. In total, 1097 articles were identified, of which 113 from internal medicine, surgery, oral medicine, and dermatology were reviewed. While comparable technological standards exist in diabetology and cardiology, in all other disciplines, comparability between studies is limited due to the number of differing AF techniques and non-standardized imaging and data analysis. Clear evidence was found for skin AF as a surrogate for blood glucose homeostasis or cardiovascular risk grading. In thyroid surgery, foremost, less experienced surgeons may benefit from the AF-guided intraoperative separation of parathyroid from thyroid tissue. There is a growing interest in AF techniques in clinical disciplines, and promising advances have been made during the past decade. However, further research and development are mandatory to overcome the existing limitations and to maximize the clinical benefits

Optical Non-Invasive Approaches to Diagnosis of Skin Diseases

A number of noninvasive approaches have been developed over the years to provide objective evaluation of the skin both in health and in disease. The advent of computers, as well as of lasers and photonics, has made it possible to develop additional techniques that were impossible a few years ago. These approaches provide the dermatologist with sensitive tools to measure the skin's condition in terms of physiologic parameters (e.g., color, erythema and pigmentation, induration, sebaceous and stratum corneum lipids, barrier function, etc.). Yet, a typical dermatologic diagnosis relies primarily on the trained eyes of the physician and to a lesser extent on information from other senses, such as touch and smell. The trained senses of the dermatologist backed by his/her brain form a powerful set of tools for evaluating the skin. The golden rule in diagnosis remains the histologic examination of a skin biopsy, a rather invasive method. These tools have served the profession well. The advent of ever faster and cheaper computers and of sensitive, inexpensive optical instrumentation of minimal dimensions provides the professional with the possibility of making objective measures of a number of skin parameters

Non-Invasive Determination of Breslow Index

Breslow index is defined as maximal thickness of cutaneous malignant melanoma measured in several slides from the top of the granular cell layer to the deepest point of invasion. Prognosis, prediction of sentinel lymph node status as well as excision margins are based on Breslow index determination. Non-invasive Breslow index determination would allow one-time procedure for melanoma clinical management which would be of utmost medical interest for several reasons: unimpaired sentinel lymph node status, low morbidity, pain and stress associated to surgical excision margins. However, as explained throughout the current chapter, such a determination requires melanoma diagnosis prior to Breslow determination. As a result, all techniques reported in this chapter (based on ultrasounds, optical waves or both), not only demonstrate their ability to determine Breslow thickness but also their ability to increase diagnosis accuracy. Ultrasonography and dermoscopy are currently evaluated in clinical environments. Diffuse reflectance spectroscopy, has been tested on tissue phantoms. Infrared microimaging and photoacoustic microscopy have shown preliminary results on fixed and paraffin-embedded tissues without staining and on xenografted tumours on mice respectively. Finally, optical coherence tomography and confocal microscopy may have a clinical interest in the management of very thin melanomas but require further studies to show their potential interest

Novel non-invasive adjunctive techniques for early oral cancer diagnosis and oral lesions examination

Oral cancer is a potentially fatal disease with an increasing incidence and an unchanged 5-year mortality rate. Unfortunately, oral cancer is often still late diagnosed, which leads to an increase in the likelihood of functional impairment due to treatment and mortality rate. Definitive diagnosis of oral cancer must be confirmed by scalpel biopsy and histological assessment. However despite its benefits, scalpel biopsy is invasive and it is burdened by a potential morbidity. Furthermore, previous studies have suggested a high degree of intraobserver and interobserver variability regarding the histological evaluation of malignancy. As a consequence, in recent years there has been a growing and persisting demand towards developing new non-invasive, practical diagnostic tools that might facilitate the early detection of oral cancer. The most investigated non-invasive adjunctive techniques are vital staining, autofluorescence, chemiluminescence, narrow band imaging, and exfoliative cytology. Aim of the review is to critically describe these adjunctive aids and, after considering the literature data, an expert opinion on the effectiveness and the possible use of each technique will be provided

Non-invasive 3D imaging of human melanocytic lesions by combined ultrasound and photoacoustic tomography: a pilot study

The accurate determination of the size and depth of infiltration is critical to the treatment and excision of melanoma and other skin cancers. However, current techniques, such as skin biopsy and histological examination, pose invasiveness, time-consumption, and have limitations in measuring at the deepest level. Non-invasive imaging techniques like dermoscopy and confocal microscopy also present limitations in accurately capturing contrast and depth information for various skin types and lesion locations. Thus, there is a pressing need for non-invasive devices capable of obtaining high-resolution 3D images of skin lesions. In this study, we introduce a novel device that combines 18 MHz ultrasound and photoacoustic tomography into a single unit, enabling the acquisition of colocalized 3D images of skin lesions. We performed in vivo measurements on 25 suspicious human skin nevi that were promptly excised following measurements. The combined ultrasound/photoacoustic tomography imaging technique exhibited a strong correlation with histological Breslow thickness between 0.2 and 3 mm, achieving a coefficient of determination (R (Formula presented.)) of 0.93, which is superior to the coefficients from the individual modalities. The results procured in our study underscore the potential of combined ultrasound and photoacoustic tomography as a promising non-invasive 3D imaging approach for evaluating human nevi and other skin lesions. Furthermore, the system allows for integration of other optical modalities such as optical coherence tomography, microscopy, or Raman spectroscopy in future applications

Developing endoscopic instrumentation and techniques for in vivo fluorescence lifetime imaging and spectroscopy

Confocal fluorescence endomicroscopes employ fibre optics along with miniaturised scanning and focussing mechanisms to allow microscopic investigation of remote tissue samples with sub-cellular resolution. For this reason they are widely used in biomedical research, both in clinical studies and in small animal imaging experiments. Fluorescence lifetime imaging microscopy (FLIM) has been shown to provide contrast between normal and unhealthy tissue in several diseases including gastro-intestinal (GI) cancer. As such, there is significant interest in developing instrumentation that will allow endoscopic confocal FLIM as this would permit the in vivo investigation of human GI tissue. This thesis describes the development and use of several instruments and techniques aimed at clinically viable in vivo fluorescence lifetime spectroscopy and confocal endomicroscopy. This research has consisted of two broad branches: the study of the fluorescence signature of healthy and diseased tissue both ex vivo and in vivo; and the development of a novel method for achieving beam scanning in confocal endomicroscopy. Firstly the tissue studies are discussed. This begins with the application of a compact steady-state diffuse reflectance/fluorescence spectrometer and a fibre-optic-coupled time-resolved spectrofluorometer to an in vivo investigation of the spectral signatures of skin cancer. This study – which involved the interrogation of 27 clinically diagnosed lesions – was carried out in collaboration with researchers at Lund University in Sweden and revealed significant differences between healthy and diseased tissue both in terms of fluorescence lifetime and steady state reflectance and fluorescence spectra. Further to this study, work is presented charting the development of a clinically viable spectrometer, which measures time-resolved fluorescence spectra with two excitation wavelengths (375 nm and 435 nm) as well as diffuse reflectance spectra. The entire system is contained within a compact trolley (120 x 70 x 55 cm) for easy transportation and safe use in a clinic. It utilises a fibre optic probe to deliver/collect light that can be inserted into the working channel of a medical endoscope meaning that the system can be used to measure diffuse reflectance and time-resolved fluorescence spectra in the GI tract in vivo. The development and testing of this system are discussed and data are presented from both ex vivo and in vivo studies of GI cancer. The second broad section of this thesis focuses more closely on confocal endomicroscopy. Firstly current methods used in this field are discussed and the sources of several drawbacks are explained. A novel approach to laser scanning endomicroscopy is then presented, which requires no moving parts and can be implemented without the need for any distal scanners or optics. This technique is similar in concept to the use of adaptive optics to focus through turbid media: it utilises a proximal spatial light modulator to correct for phase variations across a fibre imaging bundle and then to encode for arbitrary wavefronts at the distal end of that fibre bundle. Thus, it is possible to realise both focussing and beam scanning at the output of the fibre bundle with no distal components, permitting extremely compact endoscopic probes to be developed. Proof-of-principle results are presented illustrating the imaging capabilities of this novel system as well as simulations showing the achievable resolution and field of view in several feasible endoscopic configurations. Overall, this thesis contains work from two quite different projects both aimed at developing novel optical techniques for clinical diagnostic use in endoscopic procedures. The first is aimed at investigating the temporal and spectral properties of the fluorescence and reflectance signatures of cancer, while the goal of the second is to develop improved confocal endomicroscopes