Advancements in photoacoustic imaging for cancer diagnosis and treatment

Photoacoustic imaging provides in vivo morphological and functional information about tumors within surrounding tissue. By integrating ultrasound guidance, this technique enables precise localization and characterization of tumors. Moreover, the introduction of targeted contrast agents has further expanded the capabilities of photoacoustic imaging in the realm of in vivo molecular imaging. These contrast agents facilitate enhanced molecular and cellular characterization of cancer, enabling detailed insights into the disease. This review aims to provide a concise summary of the extensive research conducted in the field of Photoacoustic imaging for cancer management. It encompasses the development of the technology, its applications in clinical settings, and the advancements made in molecular imaging. By consolidating and synthesizing the existing knowledge, this review contributes to a better understanding of the potential of photoacoustic imaging in cancer care. In conclusion, photoacoustic imaging has emerged as a non-ionizing and noninvasive modality with the ability to visualize tissue's optical absorption properties while maintaining ultrasound's spatial resolution. Its integration with targeted contrast agents has enhanced molecular and cellular characterization of cancer. This review serves as a succinct overview of the extensive research conducted in the field, shedding light on the potential of photoacoustic imaging in the management of cancer.

Preoperative Ultrasound-Guided Incisional Biopsy Enhances the Pathological Accuracy of Incisional Biopsy of Cutaneous Melanoma: A Prospective Clinical Trial in Chinese Patients

OBJECTIVES

To assess the feasibility of preoperative ultrasound (US)-guided incisional biopsy through a prospective controlled clinical trial.

METHODS

This was a prospective, double-arm, single-center study of Chinese patients. Thirty patients were enrolled in the study. Fourteen patients received incisional biopsies for which the choice of biopsy area relied on a clinical evaluation, and 16 patients received incisional biopsies for which the choice of biopsy area relied on a US-guided evaluation. The following procedure was used in the US-guided incisional biopsy group: 1) clinical and dermoscopic evaluation of skin lesions; 2) US examination; 3) incisional biopsy; 4) surgical excision; and 5) histopathological examination. The same procedure was used in the non-US-guided group except without US examination.

RESULTS

In the non-US-guided group, the mean tumor thicknesses obtained from incisional biopsy and postoperative histopathological examination were 2.1 and 4.1 mm, respectively. Seven melanomas were underestimated by incisional biopsy, resulting in margins narrower than currently recommended. In the US-guided group, the mean tumor thicknesses obtained from US, incisional biopsy, and postoperative histopathological examination were 3.4, 2.9, and 2.7 mm, respectively. In only 3 melanomas was the tumor thickness of the incisional biopsy less than that of the postoperative histopathological examination, demonstrating that US-guided biopsy obtains the maximum thickness area.

CONCLUSIONS

Preoperative US-guided incisional biopsy can enhance the pathological accuracy of incisional biopsy, which may allow us to better perform surgical excision with safe peripheral surgical margins.

The emerging role of photoacoustic imaging in clinical oncology

Clinical oncology can benefit substantially from imaging technologies that reveal physiological characteristics with multiscale observations. Complementing conventional imaging modalities, photoacoustic imaging (PAI) offers rapid imaging (for example, cross-sectional imaging in real time or whole-breast scanning in 10-15 s), scalably high levels of spatial resolution, safe operation and adaptable configurations. Most importantly, this novel imaging modality provides informative optical contrast that reveals details on anatomical, functional, molecular and histological features. In this Review, we describe the current state of development of PAI and the emerging roles of this technology in cancer screening, diagnosis and therapy. We comment on the performance of cutting-edge photoacoustic platforms, and discuss their clinical applications and utility in various clinical studies. Notably, the clinical translation of PAI is accelerating in the areas of macroscopic and mesoscopic imaging for patients with breast or skin cancers, as well as in microscopic imaging for histopathology. We also highlight the potential of future developments in technological capabilities and their clinical implications, which we anticipate will lead to PAI becoming a desirable and widely used imaging modality in oncological research and practice.

The impact of incomplete clinical information and initial biopsy technique on the histopathological diagnosis of cutaneous melanoma

BACKGROUND/OBJECTIVES

Increased rates of histopathological misdiagnosis of melanoma have been associated with incisional punch more so than shave biopsy when compared with complete excisional biopsy. It is unknown how the increasing utilisation of shave biopsy may impact melanoma diagnosis. The extent to which the provision of clinical information to the pathologist may improve diagnostic accuracy remains unclear. This study assessed the impact of both initial biopsy technique and provision of adequate clinical information to pathologists on the accuracy of histopathological diagnosis of melanoma and disease progression.

METHODS

We conducted a retrospective cohort with nested case-control study of all histopathological false-negative and false-positive melanoma diagnoses from January 2014 to May 2019 from the Victorian Melanoma Service electronic database. Cases were assessed for the initial biopsy type, provision of clinical information on pathology request forms and disease progression associated with false-negative diagnosis.

RESULTS

Partial shave biopsy had higher odds of false-negative (OR 5.19, 95% CI 2.89-9.32; P < 0.001) and false-positive diagnoses (OR 1.95, 95% CI 1.45-2.63; P < 0.001) of melanoma when compared with elliptical excisional biopsy. These odds ratios were comparable with those found with incisional punch biopsy. Providing the suspected clinical diagnosis to pathologists also reduced the odds of false-negative diagnosis with melanoma progression by 3.8-fold (P = 0.02).

CONCLUSION

The choice of initial biopsy technique and providing the suspected clinical diagnosis to pathologists are important for correct histopathological diagnosis of cutaneous melanoma and prevention of further disease progression.

Impact of Shave Biopsy on Diagnosis and Management of Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Melanoma is the most lethal skin cancer. Excision biopsy is generally recommended for clinically suspicious pigmented lesions; however, a proportion of cutaneous melanomas are diagnosed by shave biopsy. A systematic review was undertaken to investigate the impact of shave biopsy on tumor staging, treatment recommendations, and prognosis.

METHODOLOGY

The MEDLINE, Embase, and Cochrane Library databases were searched for relevant articles. Data on deep margin status on shave biopsy, tumor upstaging, and additional treatments on wide local excision (WLE), disease recurrence, and survival effect were analyzed across studies.

RESULTS

Fourteen articles from 2010 to 2020 were included. In total, 3713 patients had melanoma diagnosed on shave biopsy. Meta-analysis revealed a positive deep margin in 42.9% of shave biopsies. Following WLE, change in tumor stage was reported in 7.7% of patients. Additional treatment was recommended for 2.3% of patients in the form of either further WLE and/or sentinel lymph node biopsy. There was high heterogeneity across studies in all outcomes. Four studies reported survival, while no studies found any significant difference in disease-free or overall survival between shave biopsy and other biopsy modalities.

CONCLUSIONS

Just over 40% of melanomas diagnosed on shave biopsy report a positive deep margin; however, this translated into a change in tumor stage or treatment recommendations in relatively few patients (7.7% and 2.3%, respectively), with no impact on local recurrence or survival among the studies analyzed.

Diagnosis of Cutaneous Melanoma: the Gap Between the Knowledge of General Practitioners and Dermatologists in a Brazilian Population

The early diagnosis of cutaneous melanoma provides less aggressive treatment reducing mortality. General practitioners are responsible for cancer diagnoses in the Brazilian Public Health System and therefore play a crucial role in the prevention and early detection of melanoma. To assess the melanoma knowledge of a primary healthcare physician, the general practitioner, compared to a dermatologist. General practitioners and dermatologists answered a questionnaire about melanoma and the management of suspected cases. The results of both groups were compared. The sample consisted of 80 specialists and 160 general practitioners. When asked about the "ABCDE" rule, 96.2% of the dermatologists knew about it, compared to 34.4% of the general practitioners. The percentage of dermatologists who examined the whole skin of the patient at high risk for melanoma was 90% vs. 24.5% amongst general practitioners. The most cited reasons for the absence of the examination of patients at risk for melanoma were lack of time at the consultations (17.6% specialists, 66.1% generalists) and an excessive number of patients (17.6% specialists, 61.5% generalists). General practitioner has less knowledge about melanoma compared to the dermatologists and presents deficient behaviors about patients at risk or who have suspicious lesions, indicating the need for training and continuing education.

Prospective study of patterns of surgical management in adults with primary cutaneous melanoma at high risk of spread, in Queensland, Australia

BACKGROUND

Knowledge of variation in diagnosis and surgery in high-risk primary melanoma patients is limited. We assessed frequency and determinants of diagnostic procedures, wide local excision (WLE) and sentinel lymph node biopsy (SLNB).

METHODS

People in Queensland newly diagnosed with melanoma, clinical stage 1b or 2, were recruited prospectively. Patient information was collected from questionnaires and pathology records. Differences in surgical procedures in relation to host and tumor characteristics were assessed.

RESULTS

In 787 participants, primary melanoma was diagnosed by surgical excision (74%), shave (14%), punch (12%) or incisional (1%) biopsy. General practitioners (GPs) diagnosed 80%. Diagnostic procedure differed by remoteness of residence, health sector, treating doctor's specialty and melanoma site and thickness. 766 patients had WLE, 86% by surgeons. Of 134 residual melanomas, 13 (10%) were ≤ 1 mm at diagnosis but > 1 mm at WLE, mostly after shave biopsy. SLNB was performed in 261 (33%) patients. SLNB was more common in those under 50, in remoter locations or treated by GP initially, and less common with head and neck melanoma.

CONCLUSION

Diagnostic and surgical procedures for primary melanoma vary substantially and partial biopsy can influence initial tumor microstaging. Patient, tumor and doctor characteristics influence SLNB practice.