A novel method for 3D scanning and virtual mapping of cancer resections is proposed with the goal of improving communication among the multidisciplinary cancer care team.
After oncologic resection of malignant tumors, specimens are sent to pathology for processing to determine the surgical margin status. These results are communicated in the form of a written pathology report. The current standard-of-care pathology report provides a written description of the specimen and the sites of margin sampling without any visual representation of the resected tissue. The specimen itself is typically destroyed during sectioning and analysis. This often leads to challenging communication between pathologists and surgeons when the final pathology report is confirmed. Furthermore, surgeons and pathologists are the only members of the multidisciplinary cancer care team to visualize the resected cancer specimen. We have developed a 3D scanning and specimen mapping protocol to address this unmet need. Computer-aided design (CAD) software is used to annotate the virtual specimen clearly showing sites of inking and margin sampling. This map can be utilized by various members of the multidisciplinary cancer care team.
The goal of oncologic resection is the complete removal of cancer with surgical margins microscopically clear of tumor cells. In head and neck cancer, the surgical margin status is the most important pathologic risk factor1. A positive surgical margin increases the risk of 5-year local recurrence and all-cause mortality by >90%2. Despite advances in medical technology and surgical techniques in recent years, positive margin rates in head and neck cancer remain high3. For locally advanced oral cavity cancers, the positive margin rate within the United States is 18.1%4.
For head and neck surgeons to ensure complete oncologic resection while minimizing disruption of surrounding structures, intraoperative sampling of margins via frozen section analysis (FSA) is performed. FSA provides a rapid intraoperative pathology consultation that is widely used and is the standard of care5,6,7,8,9. Fresh tissue is frozen, thinly sliced, placed on a glass slide, and stained for immediate interpretation while the patient is still under anesthesia.
Head and neck oncologic specimens present several distinct challenges in accurately assessing margin status, including the anatomic complexity of head and neck cancer specimens, the minimal reserve in the head and neck region for wide excision given the proximity to vital structures such as the eyes, face, and important nerves and vasculature, and the multiple tissue types often present in the resected specimen (i.e., mucosa, cartilage, muscle, bone)10,11. Thus, a specimen-based approach to margin analysis requires an enhanced level of communication between surgeon and pathologist12. A face-to-face conversation is often warranted to ensure correct specimen orientation and discussion of concerning margins. However, this is not always safe or feasible as it requires either the surgeon to leave the operating room (OR) while the patient remains under general anesthesia or the pathologist to leave the gross pathology lab, interrupting their workflow. In addition, there may be a significant travel time between the OR and the pathology lab, or in some cases, the pathology lab may be off-site altogether.
Following FSA, the oncologic specimen is fixed in formalin and formally processed through inking, sectioning, and margin sampling. Slides are created and microscopically interpreted by the pathologist to create a final pathology report. For complex head and neck cancer resection, this can often take 1-2 weeks. Unfortunately, processing of the specimen commonly results in the destruction of the resected cancer specimen. This may create further confusion as the final pathology report, multidisciplinary tumor board discussions, adjuvant radiation therapy planning, and re-resection in the setting of positive margins, must all proceed without a visual record of the oncologic specimen and its pathologic processing.
To address this clinical unmet need, we have developed a 3D scanning and specimen mapping protocol to enhance communication between surgeons, pathologists, and other members of the multidisciplinary cancer care team.
This protocol was performed at Vanderbilt University Medical Center under IRB#221597. Patients provided written consent for ex vivo 3D scanning and digital mapping of their surgical specimen prior to surgery and the addition of their scan to a 3D specimen model biorepository. Inclusion criteria were patients 18 and older with a suspected or biopsy-proven head and neck neoplasm undergoing surgical resection. 3D specimen maps were created based on surgeon and pathologist preference and staff availability.
This protocol follows the guidelines of the human research ethics committees of the Institutional Review Board (IRB#221597) at Vanderbilt University Medical Center. All subjects provided written informed consent prior to participation. All patient data have been de-identified.
1. Setting up the 3D scanner
2. Specimen handling
3. 3D scanning following en bloc resection of solid tumor
4. Alignment and meshing
5. Cleanup
6. Virtual 3D specimen mapping
7. Creating a distributable video
From October 2021 to April 2023, 28 head and neck oncologic specimens were 3D scanned and virtually mapped according to this protocol. These results were previously published13. The majority of the surgical specimens were squamous cell carcinoma (SCC) (86%, n = 24), with the most common anatomic subsites being oral cavity (54%, n = 15) and larynx (29%, n = 8).
In all cases, specimen maps were shared with attending surgeons and pathologists prior to the evaluation of the pathology slides and distribution of the final pathology report. In 29% (n = 8) of cases, the 3D specimen maps were used to communicate a margin of concern between surgeons and pathologists. The use of a 3D specimen map to improve multidisciplinary care communication via video-teleconferencing is shown in Figure 6.
Final margin status was recorded for each of the cases and tended to fall into one of four categories. (1) Positive margin: cancer present in the resected specimen without re-resection. (2) Close margin: Negative margins on resected specimen but the margin was within <5 mm of residual cancer. (3) Indeterminate margin: Cancer present in the main specimen when separate margin specimens from the defect were sent before or after the main specimen was resected, but it was not clear that they superseded the area positivity. (4) Negative margin: No cancer cells present in the main specimen or separate margin specimens from the defect with >5 mm clearance from the closest margin. The results are shown in Table 1.
Figure 1: Mobile cart for scanning. Mobile cart setup for optimal scanning at any location, shown here outside of the operating room. Please click here to view a larger version of this figure.
Figure 2: 3D Scanner equipment setup. Labeled scanner equipment and final scanner setup in the pathology lab. Please click here to view a larger version of this figure.
Figure 3: 3D Scanner settings. Correct scanner turntable settings and demonstration of optimal exposure settings in top left corner. Please click here to view a larger version of this figure.
Figure 4: Example 3D specimen map. Completed 3D specimen map of an oral cavity composite resection that has been virtually annotated to demonstrate sites of margin sampling during pathologic processing. Please click here to view a larger version of this figure.
Figure 5: Example 3D specimen map report. Example of the report distributed to members of the oncologic care team after specimen mapping of an L OCCR. The report is distributed as an animated video including the raw 3D scan, a virtually annotated specimen, and a key that denotes pathologic processing. Abbreviation: L OCCR = left oral cavity composite resection. Please click here to view a larger version of this figure.
Figure 6: Multidisciplinary team communication using 3D specimen map. Virtual 3D specimen map is used as a communication tool and visual reference in a teleconference between surgeons and pathologists establishing the final diagnosis for a given case. This figure was reproduced from Miller et. al.13. Please click here to view a larger version of this figure.
Table 1: Description of 3D specimen mapping cases. This table was reproduced from Miller et. al.13. Please click here to download this Table.
Traditionally, there is no visual representation of a resected cancer specimen. Pathologic processing often destroys the specimen. Prior work has demonstrated the feasibility and utility of 3D scanning of oncologic specimens followed by virtual annotation of the models to create 3D specimen maps which are representative of pathologic processing13,14,15. This provides the multidisciplinary care team with a visual model of the anatomic structure of the cancer specimen, specimen sectioning, and margin sampling locations.
The most critical steps in the protocol are obtaining a high-quality 3D scan, aligning the scan properly to replicate the 3D anatomic specimen, and creating an accurate 3D specimen map that mirrors pathologic processing. There are specific modifications that may need to be made to ensure a high-quality specimen map. First, lighting is extremely important. The optimal lighting for a high-quality 3D scan is a dim/dark room. If the scan is not of high quality, try dimming the lights further or finding a space that can be enclosed to create a dark environment. If there are still problems capturing scan data with optimal lighting, ensure that the specimen has been thoroughly rinsed and patted dry. The scanner targets have difficulty picking up shiny/reflective surfaces. Next, alignment is a key step that is influenced by the scan acquisition of each side of the specimen. Ensure that the specimen is rotated exactly 180° when flipping it over to scan the second side. If the anatomic specimen is morphologically asymmetric or has "floppy" components, it may be difficult to get two sets of scan data that can be aligned perfectly. If this is the case, it is recommended to align the scan as close as possible and trim off the excess as necessary.
Although this method has been successfully integrated into our workflow, there are limitations. First, the median 3D scan acquisition time is an average of 8 min15. If the scan is being performed for specimen-driven FSA, this time is added to the pathologic process and delivery of FSA results. However, our team finds this additional time acceptable as many of these patients require time-intensive neck dissections and/or tissue reconstructions, which continued in the operating room while this protocol is completed. Therefore, there is no overall increase in general anesthesia time for the patient. Another limitation is that the protocol does require several days of hands-on training to learn, and some aspects of the protocol can be technically challenging. Specifically, the learning curve for 3D alignment and specimen mapping is challenging, especially with more complex anatomic specimens. Additionally, although this technique was relatively easy to implement into our intraoperative workflow, this may not be generalizable to all institutions.
The technology is relatively inexpensive and the learning curve is manageable for academic centers with research personnel. At our institution, surgeons and pathologists have found this method useful to provide a visual aid of resected specimens to improve intraoperative communication and enhance understanding of the pathology report following the destruction of the specimen during processing. We believe that the use of 3D scanning and specimen mapping will become the standard of care and that pathology reports in the future will include a visual 3D model to enhance understanding of pathologic processing. Future clinical trials are necessary to investigate the clinical value of the 3D scanning and specimen mapping of surgical specimens and whether positive margin rates may be reduced using this protocol.
The potential applications of this method are vast. At our institution, intraoperative 3D scanning has been successfully adopted for other solid malignancies such as breast and musculoskeletal bone and soft tissue sarcoma. This demonstrates the potential use of this technology across various disease sites. Further, we are currently working on an augmented reality surgery protocol using 3D holograms of scanned specimens. We are investigating 3D point cloud registration to replace a 3D specimen hologram back into the resection bed to guide re-resection of close or positive margins in real time.
The authors have nothing to disclose.
This work was supported by a Vanderbilt Clinical Oncology Research Career Development Program (K12 NCI 2K12CA090625-22A1), the NIH/National Institute for Deafness and Communication Disorders (R25 DC020728), Vanderbilt-Ingram Cancer Center Support Grant (P30CA068485) and Swim Across America.
Computer Aided Design Software | MeshMixer | Virtual annotation software for 3D models | |
Digital Camera or Cameraphone | iPhone | May use iPhone camera or any digital camera available | |
EinScan SP V2 Platinum Desktop 3D Scanner | Shining 3D | 3D scanner hardware | |
ExScan Software; Solid Edge SHINING 3D Edition | Shining 3D | 3D capture software included with purchase of 3D Scanner | |
External Mouse | Microsoft | ||
Laptop Computer | Dell XP5 | 00355-60734-40310-AAOEM | Laptop Requirements: USB: 1 ×USB 2.0 or 3.0; OS: Win 7, 8 or 10 (64 bit); Graphic Card: Nvidia series; Graphic memory: >1 G; CPU: Dual-core i5 or higher; Memory: >8 G |
Microsoft Office Suite | Microsoft | ||
Mobile Presentation Cart | Oklahoma Sound | PRC450 | |
PowerPoint Software | Microsoft Office | Presentation software | |
Sit-Stand Mobile Desk Cart | Seville Classics | ||
USB-c Device Converter | TRIPP-LITE | U442-DOCK3-B | Necessary only if laptop does not have USB |