Assessment of bony resection margins in oral cancer using elastic scattering spectroscopy: a study on archival material

An Update on Surgical Margins in the Head Neck Squamous Cell Carcinoma: Assessment, Clinical Outcome, and Future Directions

PURPOSE OF REVIEW

Failure to achieve tumor-free margins is the single largest cause of death for head neck cancer patients. At the same time, it is the only factor that is in complete control of the surgeon. This review summarizes evidence for the definition, clinical implications, and methods to achieve optimal margins.

RECENT FINDINGS

The previous universally followed definition of adequate margin (5 mm in final histopathology) has been disputed. Various biological, optical, and imaging adjuncts can aid in achieving optimal margins. Extent of resection and margins in human papilloma virus (HPV)-positive oropharyngeal cancers and following induction chemotherapy remain controversial. Though practiced widely, frozen section-guided margin revision has not conclusively shown improved local control rates. The role of molecular assessment of margins is promising but not established. The definition of adequate margin differs according to the site in the head neck region. Currently, the 5-mm margin at final histopathology is the most commonly accepted definition of an "adequate" margin.

Oral cancer diagnosis and perspectives in India

Globally, oral cancer is the sixth most common type of cancer with India contributing to almost one-third of the total burden and the second country having the highest number of oral cancer cases. Oral squamous cell carcinoma (OSCC) dominates all the oral cancer cases with potentially malignant disorders, which is also recognized as a detectable pre-clinical phase of oral cancer. Tobacco consumption including smokeless tobacco, betel-quid chewing, excessive alcohol consumption, unhygienic oral condition, and sustained viral infections that include the human papillomavirus are some of the risk aspects for the incidence of oral cancer. Lack of knowledge, variations in exposure to the environment, and behavioral risk factors indicate a wide variation in the global incidence and increases the mortality rate. This review describes various risk factors related to the occurrence of oral cancer, the statistics of the distribution of oral cancer in India by various virtues, and the socio-economic positions. The various conventional diagnostic techniques used routinely for detection of the oral cancer are discussed along with advanced techniques. This review also focusses on the novel techniques developed by Indian researchers that have huge potential for application in oral cancer diagnosis.

Intraoperative cytological examination of bone medullary. A useful technique to predict the extension of bone invasion in segmental mandibulectomy

AIM

The main of the present report is to evaluate the utility of intraoperative cytological analysis of medullary bone to predict the extension of bone infiltration in segmental mandibulectomy.

MATERIALS AND METHOD

Between the years 2016 and 2018, a total of 17 previously untreated patients with squamous cell carcinoma of the oral cavity underwent a segmental mandibular resection and intraoperative cytological analysis of the bone medullary at Virgen de las Nieves University Hospital (HUVN). The results of the intraoperative cytological analysis were compared with the result of the postoperative histopathological examination and sensitivity, specificity, positive predictive value, and negative predictive value of the test were calculated.

RESULTS

Cytological analysis was positive in three patients and the bone resection was consequently extended. All the extensions of these bone margins were clean following the postoperative histological examination. However, two other patients previously classified as clean with intraoperative cytological analysis of bone medullary presented infiltration of bone margins postoperatively. The protocol demonstrated a high negative predictive value (85,7%). The positive predictive value, sensitivity, and specificity were 33,3%, 33,3%, and 85,7% respectively.

CONCLUSION

Intraoperative cytological analysis of bone medullary could represent an easy, fast, reliable and inexpensive method to reduce the rate of r1 surgeries attributable to the infiltration of the bone margin. This may have a positive impact on overall survival without increasing the duration and the iatrogenicity of surgery.

Development of a Rapid Analysis Method for Bone Resection Margins for Oral Squamous Cell Carcinoma by Immunoblotting

The purpose of this proof-of-principle study was to develop a rapid and approachable method to analyse bone resection margins in patients with oral squamous cell carcinoma (OSCC) in an intraoperative setting, similar to assessing frozen sections of soft tissue. Bone excision and risk of remaining tumour cells could be minimised, thus improving reconstruction measures and facilitating convalescence. Frozen, sawed wafers of porcine bone artificially combined with porcine skin (simulating OSCC properties) were used to develop and evaluate a new molecular method: protein transfer from non-decalcified, sawed wafers onto a membrane stained by immunofluorescence (Tissue-ProtTrans). Tissue-ProtTrans was based on the detection of keratin 5/6 as a marker of tumour cells. The results were compared to standard immunohistochemistry (IHC) and H&E results of the same wafers after decalcification. Tissue-ProtTrans resulted in a total assay time of 3.5 h using the Trans-Blot® Turbo™ Transfer System (Bio-Rad) for protein transfer. Amersham Protran® Premium Nitrocellulose Membranes 0.2 µm (GE Healthcare) were stained with a primary antibody to keratin 5/6 (Dako Agilent) and a secondary antibody labelled with IRDye® 800CW (LI-COR). Visualisation was performed with an infrared laser scanner (Odyssey). Upon comparison, five independent experiments on porcine specimens processed with the Tissue-ProtTrans showed similar results to standard IHC and H&E analysis. In comparison to standard IHC results (requiring several days due to decalcification) Tissue-ProtTrans provided similar results, but was much faster (3.5 h). This highly promising method has good potential for further time reduction and will be suitable for intraoperative assessment.

Evaluation of bone resection margins of segmental mandibulectomy for oral squamous cell carcinoma

Resection margins are frequently studied in patients with oral squamous cell carcinoma and are accepted as a constant prognostic factor. While most evidence is based on soft tissue margins, reported data for bone resection margins are scarce. The aim of this retrospective study was to evaluate and determine the utility of surgical margins in bone resections for oral cavity squamous cell carcinoma (OCSCC). The status of bone resection margins and their impact on survival was investigated in patients who had undergone segmental mandibulectomy for OCSCC. Medical records were retrieved for the years 2000-2012; 127 patients were identified and included in the study. Tumour-positive bone resection margins were found in 21% of the patients. The 5-year overall survival was significantly lower in this group (P<0.005). Therefore, there is a need for intraoperative feedback on the status of bone resection margins to enable immediate additional resection where necessary. Although the lack of intraoperative methods for the evaluation of bone tissue has been addressed by many authors, there is still no reliable method for widespread use. Future research should focus on an objective, accurate, and rapid method of intraoperative assessment for the entire bone resection margin to optimize patient outcomes.

Evaluation of intraoperative cytological assessment of bone resection margins in patients with oral squamous cell carcinoma

BACKGROUND

Frozen sections are routinely applied to control for adequate resection margins. In cases in which carcinoma infiltrates bone, the intraoperative microscopic assessment of bone margins remains challenging due to technical difficulties to section native bone. The objective of the current study was to evaluate an intraoperative cytological approach to control bone resection margins in patients with bone-infiltrating oral squamous cell carcinomas.

METHODS

A total of 174 cytological preparations obtained from bone margins of bone-infiltrating oral squamous cell carcinomas (28 patients) were assessed intraoperatively and compared with the corresponding histological findings. In a validation cohort (45 patients) the intraoperative cytological assessment of bone resection margins (ICAB) (104 margins) was evaluated as a diagnostic tool for routine clinical application.

RESULTS

In the first patient cohort, the ICAB revealed 95.3% sensitivity and 96% specificity. The results provided an accuracy of 95.7% with a significant correlation noted between cytological and histological results (κ, 0.91; P < .001), and a positive predictive value and negative predictive value of 93.8% and 96.9%, respectively. In the validation cohort, ICAB revealed 80% sensitivity and 98.9% specificity with 98% accuracy. There was a significant correlation found between cytological and histological results (κ, 0.91; P < .001), providing a positive predictive value and negative predictive value of 80% and 98%, respectively. ICAB could predict final resection status at bone margins with 80% sensitivity and 97.5% specificity. A significant correlation was found between the cytological and histological resection status at bone margins (κ, 0,75; P < .001).

CONCLUSIONS

ICAB could supplement intraoperative frozen sections of soft tissue margins as a standard procedure to control for adequate resection at bone margins.

Integrated Device for in Vivo Fine Needle Aspiration Biopsy and Elastic Scattering Spectroscopy in Preoperative Thyroid Nodules

Thyroid nodules are a frequent clinical finding and the most common endocrine malignancy is thyroid cancer. The standard of care in the management of a patient with a thyroid nodule is to perform a preoperative fine needle aspiration (FNA) biopsy of the suspect nodule under ultrasound imaging guidance. In a significant percentage of the cases, cytological assessment of the biopsy material yields indeterminate results, the consequence of which is diagnostic thyroidectomy. Unfortunately, 75–80% of diagnostic thyroidectomies following indeterminate cytology result in benign designation by post-surgery histopathology, indicating potentially unnecessary surgeries. Clearly, the potential exists for the improvement in patient care and the reduction of overall procedure costs if an improved preoperative diagnostic technique was developed. Elastic scattering spectroscopy (ESS) is an optical biopsy technique that is mediated by optical fiber probes and has been shown to be effective in differentiating benign from malignant thyroid tissue in ex vivo surgical tissue samples. The goal of the current research was to integrate the ESS fiber optic probes into a device that can also collect cells for cytological assessment and, thus, enable concurrent spectroscopic interrogation and biopsy of a suspect nodule with a single needle penetration. The primary challenges to designing the device included miniaturizing the standard ESS fiber optic probe to fit within an FNA needle and maintaining the needle’s aspiration functionality. We demonstrate the value of the fabricated prototype devices by assessing their preliminary performance in an on-going clinical study with >120 patients. The devices have proven to be clinically friendly, collecting both aspirated cells and optical data from the same location in thyroid nodules and with minimal disruption of clinical procedure. In the future, such integrated devices could be used to complement FNA-based cytological results and have the potential to both reduce the number of diagnostic thyroidectomies on benign nodules and improve the surgical approach for patients with thyroid malignancies, thereby, decreasing healthcare costs and improving patient outcomes.

Preoperative discrimination of benign from malignant disease in thyroid nodules with indeterminate cytology using elastic light-scattering spectroscopy

Thyroid nodules are common and often require fine needle aspiration biopsy (FNAB) to determine the presence of malignancy to direct therapy. Unfortunately, approximately 15-30% of thyroid nodules evaluated by FNAB are not clearly benign or malignant by cytology alone. These patients require surgery for the purpose of diagnosis alone; most of these nodules ultimately prove to be benign. Elastic light scattering spectroscopy (ESS) that measures the spectral differences between benign and malignant thyroid nodules has shown promise in improving preoperative determination of benign status of thyroid nodules. We describe the results of a large, prospective, blinded study validating the ESS algorithm in patients with thyroid nodules. An ESS system was used to acquire spectra from human thyroid tissue. Spectroscopic results were compared to the histopathology of the biopsy samples. Sensitivity and specificity of the ESS system in the differentiation of benign from malignant thyroid nodules are 74% and 90% respectively, with a negative predictive value of 97%. These data suggest that ESS has the potential for use in real time diagnosis of thyroid nodules as an adjunct to FNAB cytology.

Elastic scattering spectroscopy in assessing skin lesions: an "in vivo" study

INTRODUCTION

Elastic scattering spectroscopy (ESS) has been shown to be accurate in the identification of abnormalities of soft tissue. These include ischemia and inflammation, pre-cancer and cancer. The aim of this study was to compare findings of ESS with gold standard histopathology in patients with various skin lesions.

MATERIALS AND METHODS

Seventy-three patients with clinically suspicious facial skin lesions were included. Those lesions with the surrounding innocuous skin were interrogated by ESS, biopsies were taken and examined histopathologically; the results were then compared.

RESULTS

The preliminary analysis showed obvious spectral differences between normal and pathological skin. Spectral differences were identified when comparing benign skin conditions to malignant ones. Spectral differences were identified between basal cell carcinomas and other skin lesions.

CONCLUSIONS

This preliminary study shows that ESS can distinguish between normal, benign and malignant skin conditions.

The future of medical diagnostics: review paper

While histopathology of excised tissue remains the gold standard for diagnosis, several new, non-invasive diagnostic techniques are being developed. They rely on physical and biochemical changes that precede and mirror malignant change within tissue. The basic principle involves simple optical techniques of tissue interrogation. Their accuracy, expressed as sensitivity and specificity, are reported in a number of studies suggests that they have a potential for cost effective, real-time, in situ diagnosis.

We review the Third Scientific Meeting of the Head and Neck Optical Diagnostics Society held in Congress Innsbruck, Innsbruck, Austria on the 11th May 2011. For the first time the HNODS Annual Scientific Meeting was held in association with the International Photodynamic Association (IPA) and the European Platform for Photodynamic Medicine (EPPM). The aim was to enhance the interdisciplinary aspects of optical diagnostics and other photodynamic applications. The meeting included 2 sections: oral communication sessions running in parallel to the IPA programme and poster presentation sessions combined with the IPA and EPPM posters sessions.

Elastic light-scattering spectroscopy for discrimination of benign from malignant disease in thyroid nodules

BACKGROUND

Thyroid cancer is the most common endocrine malignancy. The current standard of diagnosis, fine-needle aspiration biopsy, yields approximately 10-25% of indeterminate results leading to twice as many thyroidectomies for further diagnosis. Elastic scattering spectroscopy (ESS) is a new, minimally invasive optical-biopsy technique mediated by fiber-optic probes that is sensitive to cellular and subcellular morphological features. We assessed the diagnostic potential of ESS in the thyroid to differentiate benign from malignant thyroid nodules as determined by histology.

METHODS

Under an IRB approved protocol, 36 surgical patients (n = 21 benign thyroid nodules, n = 15 malignant tumors) had collection of ESS data from their fresh ex vivo thyroidectomy specimens. Using surgical pathology as our gold standard, spectral analyses were performed using a training set; these data were used to assess the ESS diagnostic potential using the leave-one-out technique.

RESULTS

Our test set was 75% sensitive and 95% specific in differentiating benign from malignant thyroid lesions, with a positive predictive value (PPV) of 0.92 and a negative predictive value (NPV) of 0.83.

CONCLUSIONS

The ESS can accurately distinguish benign vs malignant thyroid lesions with high PPV and NPV. With further validation ESS could potentially be used as an in situ real-time diagnostic tool or as an adjunct to conventional cytology.

In vitro examination of suspicious oral lesions using optical coherence tomography

We compared findings of optical coherence tomography (OCT) with histopathological results of suspicious oral lesions to assess the feasibility of using OCT to identify malignant tissue. Thirty-four oral lesions from 27 patients had swept-source frequency-domain OCT. Four variables were assessed (changes in keratin, epithelial, and sub-epithelial layers, and identification of the basement membrane) and from this we calculated whether or not there were architectural changes. These data were then compared with histopathological results. Two clinicians, who were unaware of the clinical and histopathological diagnoses, decided whether biopsy was necessary. The basement membrane was recognised in only 15 oral lesions. OCT could identify diseased areas but could not provide a diagnosis or differentiate between lesions. The two clinicians, who recommended biopsy agreed in all cases. This pilot study confirms the feasibility of using OCT to identify architectural changes in malignant tissues.

Assessment of oral premalignancy using elastic scattering spectroscopy

Optical spectroscopy systems have been involved in various clinical fields; however the main interest is still in the diagnosis of premalignant/malignant lesions. The aim of this study was to compare findings of Elastic Scattering Spectroscopy (ESS) with histopathology of oral tissues to see if this technique could be used as an adjunct or alternative to histopathology in identifying dysplasia. The technique involves the use of Mie scattering and is a simple non-invasive method of tissue interrogation. Twenty-five oral sites from 25 patients who presented with oral leukoplakia were examined by ESS using a pulsed xenon-arc lamp. Surgical biopsies were acquired from each of the examination sites. The results of the acquired spectra were then compared with histopathology. Two sets of spectra were obtained, and by using a linear discriminant analysis, a sensitivity of 72% and a specificity of 75% were obtained. These results are promising and could suggest that ESS may be able to identify dysplasia in oral tissues. To prove the usefulness of the ESS in dysplasia detection in oral tissues conclusively, a larger body of data is needed. We aim to continue this study to obtain more data in an attempt to increase the accuracy of the technique. Large, multi-centre trails are needed for each anatomical site, in order to gather more information about the differences between normal and dysplastic tissue.

Optical techniques in diagnosis of head and neck malignancy

The "gold standard" of assessing pathological changes in tissue is currently histopathology. However, the processing of biopsy material and the interpretation of the results inevitably leads to diagnostic delay and the added possibility of taking an unrepresentative sample. Recently, there has been increasing interest in the use of optical spectroscopy systems to be able to provide tissue diagnosis in real-time, non-invasively and in situ. These systems rely on the fact that the optical spectrum derived from any tissue will contain information about the histological and biochemical make up of that tissue. The technique has not only been shown to have a role in the detection of dysplasia and malignancy but also in performing guided biopsies, monitoring of haemoglobin tissue perfusion in free-flaps and therapeutic drug levels during chemo- and photodynamic therapy. The assessment of surgical margins and a role in sentinel node biopsy are also interesting developments. The obvious advantages of being able to accurately diagnose pathology without the need to remove a tissue sample diminish patient trauma as well as having financial implications.