Use of Intraoperative Frozen Section to Assess Final Tumor Margin Status in Patients Undergoing Surgery for Oral Cavity Squamous Cell Carcinoma

A Prospective Double-Blinded Comparison of Reflectance Confocal Microscopy with Conventional Histopathology for In Vivo Assessment in Oral Cancer

PURPOSE

We investigated reflectance confocal microscopy (RCM) as a possible noninvasive approach for the diagnosis of cancer and real-time assessment of surgical margins.

EXPERIMENTAL DESIGN

In a phase I study on 20 patients, we established the RCM imaging morphologic features that distinguish oral squamous cell carcinoma (OSCC) from normal tissue with a newly developed intraoral RCM probe. Our subsequent phase II prospective double-blinded study in 60 patients tested the diagnostic accuracy of RCM against histopathology. Five RCM videos from the tumor and five from normal surrounding mucosa were collected on each patient, followed by a 3-mm punch biopsy of the imaged area. An experienced RCM reader, who was blinded to biopsy location and histologic diagnosis, examined the videos from both regions and classified each as "tumor" or "not tumor" based on RCM features established in phase I. Hematoxylin and eosin slides from the biopsies were read by a pathologist who was blinded to RCM results. Using histology as the gold standard, we calculated the sensitivity and specificity of RCM.

RESULTS

We report a high agreement between the blinded readers (95% for normal tissue and 81.7% for tumors), high specificity (98.3%) and negative predictive values (96.6%) for normal tissue identification, and high sensitivity (90%) and positive predictive values (88.2%) for tumor detection.

CONCLUSIONS

RCM imaging is a promising technology for noninvasive in vivo diagnosis of OSCC and for real-time intraoperative evaluation of mucosal surgical margins. Its inherent constraint, however, stems from the diminished capability to evaluate structures located at more substantial depths within the tissue.

Clinical validation of the accuracy of an intra-operative assessment tool using 3D ultrasound compared to histopathology in patients with squamous cell carcinoma of the tongue

BACKGROUND

Histopathological analysis often shows close resection margins after surgical removal of tongue squamous cell carcinoma (TSCC). This study aimed to investigate the agreement between intraoperative 3D ultrasound (US) margin assessment and postoperative histopathology of resected TSCC.

METHODS

In this study, ten patients were prospectively included. Three fiducial cannulas were inserted into the specimen. To acquire a motorized 3D US volume, the resected specimen was submerged in saline, after which images were acquired while the probe moved over the specimen. The US volumes were annotated twice: (1) automatically and (2) manually, with the automatic segmentation as initialization. After standardized histopathological processing, all hematoxylin-eosin whole slide images (WSI) were included for analysis. Corresponding US images were found based on the known WSI spacing and fiducials. Blinded observers measured the tumor thickness and the margin in the caudal, deep, and cranial directions on every slide. The anterior and posterior margin was measured per specimen.

RESULTS

The mean difference in all measurements between manually segmented US and histopathology was 2.34 (SD: ±3.34) mm, and Spearman's rank correlation coefficient was 0.733 (p < 0.001). The smallest mean difference was in the tumor thickness with 0.80 (SD: ±2.44) mm and a correlation of 0.836 (p < 0.001). Limitations were observed in the caudal region, where no correlation was found.

CONCLUSION

This study shows that 3D US and histopathology have a moderate to strong statistically significant correlation (r = 0.733; p < 0.001) and a mean difference between the modalities of 2.3 mm (95%CI: -4.2; 8.9). Future research should focus on patient outcomes regarding resection margins.

Association of the Specimen and Tumor Bed Margin Status with Local Recurrence and Survival in Open Partial Laryngectomy

Background/Objectives: Positive margins are associated with locoregional recurrence in early laryngeal cancer. The aim of this study was to evaluate the impacts of specimen-driven (ex vivo) positive margins on patients with early-stage laryngeal cancer whose tumor bed (defect-driven) margins had been negative. Methods: A retrospective study was performed on 60 consecutive T1b/T2 glottic cancer patients who underwent open frontolateral laryngectomy. The intraoperative margins were obtained from the tumor bed. Their recurrence and disease-free survival were evaluated. In all cases, negative margins were obtained from the surgical bed. The impact of positive margins from the specimen was evaluated in a paraffin study. Results: Among 10 patients with positive margins in the specimen, six experienced local relapse, and among 50 patients with negative margins in the specimen, three developed recurrence. The 5-year disease-free survival rates were 37.5% and 93.9%, respectively (p < 0.001; log-rank). Even with negative margins in the surgical bed, patients with positive margins in the specimen at the final histopathological examination had a 3.5-fold higher chance of developing local recurrence than those with negative margins (HR = 13.993; 95% CI: 3.479-56.281; p < 0.001; univariate Cox regression). Conclusions: Specimen-driven positive margins represent a significant risk factor for local recurrence, even under negative margins at the tumor bed.

Intraoperative Ultrasound for the Management of Oral Tongue Cancer: a Systematic Review and Meta-Analysis

Objective

To evaluate for correlation between intraoperative ultrasound (IOUS)-measured tumor thickness (TT) (uTT) and histopathological TT (hTT), and to compare IOUS-assisted resection with conventional resection in patients with oral tongue cancers.

Data Sources

Ovid MEDLINE (1946-2023), Embase.com (1947-2023), and Web of Science (All Databases 1900-2023).

Review Methods

Inclusion criteria were the use of IOUS for the management of oral tongue cancer. Studies that did not report quantitative data were excluded. Additionally, studies that were not contributory to meta-analysis, or a narrative analysis of pooled results were excluded. Selection was carried out by 2 reviewers. A total of 2417 studies were initially identified, with 12 ultimately being included in this review, and 7 included in the meta-analysis. Data were extracted by 2 investigators and were pooled using a random-effects model.

Results

Our meta-analysis reveals a pooled correlation coefficient of 0.92 (95% confidence interval: 0.80-0.96) for studies comparing uTT to hTT. Studies comparing IOUS-assisted resection to conventional resection found IOUS-assisted resection yielded wider nearest margins in all studies reporting this outcome.

Conclusion

IOUS reliably measures TT, similarly to that of histopathology measurement. IOUS-assisted resection, which allows the surgeon to view the deep extent of tumor invasion, may increase closest radial margin distance compared to conventional resection. IOUS-assisted resection may represent a more reliable approach to achieving clear margins than conventional resection.

Feasibility of an MR-based digital specimen for tongue cancer resection specimens: a novel approach for margin evaluation

Objective

This study explores the feasibility of ex-vivo high-field magnetic resonance (MR) imaging to create digital a three-dimensional (3D) representations of tongue cancer specimens, referred to as the "MR-based digital specimen" (MR-DS). The aim was to create a method to assist surgeons in identifying and localizing inadequate resection margins during surgery, a critical factor in achieving locoregional control.

Methods

Fresh resection specimens of nine tongue cancer patients were imaged in a 7 Tesla small-bore MR, using a high-resolution multislice and 3D T2-weighted Turbo Spin Echo. Two independent radiologists (R1 and R2) outlined the tumor and mucosa on the MR-images whereafter the outlines were configured to an MR-DS. A color map was projected on the MR-DS, mapping the inadequate margins according to R1 and R2. We compared the hematoxylin-eosin-based digital specimen (HE-DS), which is a histopathological 3D representation derived from HE stained sections, with its corresponding MR-images. In line with conventional histopathological assessment, all digital specimens were divided into five anatomical regions (anterior, posterior, craniomedial, caudolateral and deep central). Over- and underestimation 95th-percentile Hausdorff-distances were calculated between the radiologist- and histopathologist-determined tumor outlines. The MR-DS' diagnostic accuracy for inadequate margin detection (i.e. sensitivity and specificity) was determined in two ways: with conventional histopathology and HE-DS as reference.

Results

Using conventional histopathology as a reference, R1 achieved 77% sensitivity and 50% specificity, while R2 achieved 65% sensitivity and 57% specificity. When referencing to the HE-DS, R1 achieved 94% sensitivity and 61% specificity, while R2 achieved 88% sensitivity and 71% specificity. Range of over- and underestimation 95HD was 0.9 mm - 11.8 mm and 0.0 mm - 5.3 mm, respectively.

Conclusion

This proof of concept for volumetric assessment of resection margins using MR-DSs, demonstrates promising potential for further development. Overall, sensitivity is higher than specificity for inadequate margin detection, because of the radiologist's tendency to overestimate tumor size.

Diagnostic accuracy of intraoperative frozen section for margin evaluation of oral cavity squamous cell carcinoma

OBJECTIVES

Intraoperative frozen-section evaluation is a valuable technique for detecting positive margins intraoperatively for oral squamous cell carcinoma. We conducted this study to determine the diagnostic accuracy of frozen section in detecting margin status and the effect of tumor grade and stage on diagnostic accuracy.

RESULTS

A total of 251 biopsy-proven cases of oral squamous cell carcinoma were included in this study. The tissue specimen resected during surgery was sent to the laboratory for frozen section evaluation. The frozen section results were then compared with the permanent section results to determine the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy. The mean age of the patients included in the study was 51.65 ± 10.03 years, with male predominance (55.4%). The overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of frozen section were 88.81%, 94.84%, 95.20%, 88.10%, and 91.63%, respectively. We conclude that frozen section is a useful technique in determining the margin status intraoperatively in oral cancers, with high diagnostic accuracy. Moreover, certain clinical parameters such as age, gender, disease duration, and tumor stage and grade appear to affect the diagnostic accuracy of frozen section.

Comparison of image quality of 3D ultrasound: motorized acquisition versus freehand navigated acquisition, a phantom study

PURPOSE

Intra-operative assessment of resection margins during oncological surgery is a field that needs improvement. Ultrasound (US) shows the potential to fulfill this need, but this imaging technique is highly operator-dependent. A 3D US image of the whole specimen may remedy the operator dependence. This study aims to compare and evaluate the image quality of 3D US between freehand acquisition (FA) and motorized acquisition (MA).

METHODS

Multiple 3D US volumes of a commercial phantom were acquired in motorized and freehand fashion. FA images were collected with electromagnetic navigation. An integrated algorithm reconstructed the FA images. MA images were stacked into a 3D volume. The image quality is evaluated following the metrics: contrast resolution, axial and elevation resolution, axial and elevation distance calibration, stability, inter-operator variability, and intra-operator variability. A linear mixed model determined statistical differences between FA and MA for these metrics.

RESULTS

The MA results in a statistically significant lower error of axial distance calibration (p < 0.0001) and higher stability (p < 0.0001) than FA. On the other hand, the FA has a better elevation resolution (p < 0.003) than the MA.

CONCLUSION

MA results in better image quality of 3D US than the FA method based on axial distance calibration, stability, and variability. This study suggests acquiring 3D US volumes for intra-operative ex vivo margin assessment in a motorized fashion.

Pre-resection Intraoperative Core Biopsies in Oral Tongue Cancer-A Pilot Study

OBJECTIVE

To assess a novel intraoperative core biopsy technique to provide enhanced guidance in partial glossectomies.

METHODS

All patients diagnosed with squamous cell carcinoma of the oral tongue were eligible for study participation. Following anesthesia, the planned resection and three points midway between the gross tumor and the intended ablation were marked. A core biopsy was performed with a needle spring on each point and sent for frozen sections. The initially planned resection was executed if the cores returned free of tumor. In case of a positive core biopsy, a new 1-1.5 cm margin was marked around that point. The main outcome measure was the closest final margin diameter, especially the deep ones. Other outcome measures were the core biopsies' sensitivity, specificity, and negative predictive value. Complications were recorded.

RESULTS

The final margins of 10 patients undergoing intraoperative core biopsies and 20 matched controls were analyzed. One patient had two positive cores and final negative margins after modifying the resection accordingly. Another patient had a positive biopsy diagnosed only on final pathology, and one close final margin. Patients that were operated with the new technique had larger margins compared to the controls: median (interquartile range) closest margin 5.95 (3.97; 9.63) mm versus 4 (2.25; 5) mm (p = 0.074) and median deep margin 8.6 (6.16; 10) mm versus 5 (3;10) mm (p = 0.411), respectively. There were no complications.

CONCLUSION

A novel pre-resection intraoperative biopsy technique is presented. Core biopsies taken during glossectomies have the potential to prevent inadequate margins.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:2232-2236, 2023.

Immediate resection of positive margins improves local control in oral tongue cancer

OBJECTIVES

This study investigates the impact of immediate resection of positive margins on local control of oral tongue cancer.

MATERIALS AND METHODS

We analyzed 273 consecutive oral tongue cancers resected from 2013 to 2018. Additional resection was performed in cases during the initial operation based on surgeon inspection of the specimen and/or frozen margins. Positive margins were defined as invasive carcinoma/high-grade dysplasia < 1 mm from the inked edge. Patients were grouped as follows: negative margin (Group 1); positive margin with immediate additional tissue resection (Group 2); and positive margin without additional tissue resection (Group 3).

RESULTS

Overall, the rate of local recurrence was 7.7 % (21/273), and the rate of positive main specimen margin was 17.9 %. Of these patients, 38.8 % (19/49) underwent immediate additional resection of the presumed positive margin. Group 3 had higher local recurrence rates than Group 1 after adjustment for T-stage (aHR 2.8 [95 % CI 1.0-7.7], p = 0.04). Group 2 had similar rates of local recurrence (aHR 0.45 [95 % CI 0.06-3.6], p = 0.45). Three year local recurrence free survival for Groups 1, 2, and 3 were 91 %, 92 % and 73 %, respectively. Compared to the main specimen margin, sensitivity of intraoperative frozen tumor bed margins was 17.4 %, and specificity was 95 %.

CONCLUSION

In patients with positive main specimen margins, anticipation and detection in real-time with immediate additional tissue resection reduced local recurrence to rates similar to those with negative main specimen margins. These findings support the use of technology to provide real-time intraoperative margin data and guide additional resection for improved local control.

Ultrasound-guided resection for squamous cell carcinoma of the buccal mucosa: A feasibility study

BACKGROUND

Image-guided surgery could help obtain clear (≥5.0 mm) resection margins. This feasibility study investigated ultrasound-guided resection accuracy of buccal mucosa squamous cell carcinoma (BMSCC).

METHODS

MRI and ultrasound measurements of tumor thickness were compared to histology in 13 BMSCC-patients. Ultrasound measured margins (at five locations) on the specimen were compared to the corresponding histological margins.

RESULTS

Accuracy of in- and ex-vivo ultrasound (mean deviation from histology: 1.6 mm) for measuring tumor thickness was comparable to MRI (mean deviation from histology: 2.6 mm). The sensitivity to detect clear margins using ex-vivo ultrasound was low (48%). If an ex-vivo ultrasound cutoff of ≥7.5 mm would be used, the sensitivity would increase to 86%.

CONCLUSIONS

Ultrasound-guided resection of BMSCC's is feasible. In- and ex-vivo ultrasound measure tumor thickness in BMSCC accurately. We recommend ≥7.5 mm resection margins on ex-vivo ultrasound to obtain histological clear margins. Additional research is required to establish the effect of 7.5 mm ultrasound cutoff.