The use of fluorescence might improve the performance of the sentinel lymph node procedure in patients with colon cancer. This systematic review was conducted to gain insight in the performance and applicability of the sentinel lymph node procedure using fluorescence. A systematic literature search was performed. Databases were searched for prospective studies concerning sentinel node identification using fluorescence in colon cancer. Detection rate, accuracy rate and sensitivity of the sentinel lymph node procedure were calculated for early stage (T1-T2) and more invasive (T3-T4) tumours. Analyses of five included studies showed for respectively T3-T4 and T1-T2 tumours a detection rate of 90 % and 91 %, an accuracy rate of 77 % and 98 %, and a sensitivity of 30 % and 80 %. The sentinel lymph node procedure using fluorescence in early stage (T1-T2) colon cancer seems to be promising. Larger cohorts are necessary to confirm these results.

Background: Patients with cT1-2 colon cancer (CC) have a 10–20% risk of lymph node metastases. Sentinel lymph node identification (SLNi) could improve staging and reduce morbidity in future organ-preserving CC surgery. This pilot study aimed to assess safety and feasibility of robot-assisted fluorescence-guided SLNi using submucosally injected indocyanine green (ICG) in patients with cT1-2N0M0 CC. Methods: Ten consecutive patients with cT1-2N0M0 CC were included in this prospective feasibility study. Intraoperative submucosal, peritumoral injection of ICG was performed during a colonoscopy. Subsequently, the near-infrared fluorescence ‘Firefly’ mode of the da Vinci Xi robotic surgical system was used for SLNi. SLNs were marked with a suture, after which a segmental colectomy was performed. The SLN was postoperatively ultrastaged using serial slicing and immunohistochemistry, in addition to the standard pathological examination of the specimen. Colonoscopy time, detection time (time from ICG injection to first SLNi), and total SLNi time were measured (time from the start of colonoscopy to start of segmental resection). Intraoperative, postoperative, and pathological outcomes were registered. Results: In all patients, at least one SLN was identified (mean 2.3 SLNs, SLN diameter range 1–13 mm). No tracer-related adverse events were noted. Median colonoscopy time was 12 min, detection time was 6 min, and total SLNi time was 30.5 min. Two patients had lymph node metastases present in the SLN, and there were no patients with false negative SLNs. No patient was upstaged due to ultrastaging of the SLN after an initial negative standard pathological examination. Half of the patients unexpectedly had pT3 tumours. Conclusions: Robot-assisted fluorescence-guided SLNi using submucosally injected ICG in ten patients with cT1-2N0M0 CC was safe and feasible. SLNi was performed in an acceptable timespan and SLNs down to 1 mm were detected. All lymph node metastases would have been detected if SLN biopsy had been performed.

(1) Introduction: Near-infrared fluorescence (NIRF) combined with tumour-targeted tracers, such as bevacizumab-800CW, could aid surgical decision-making. This study explored the use of IRDye800CW, conjugated to bevacizumab, with four commercially available NIRF laparoscopes optimised for indocyanine green (ICG). (2) Methods: A (lymph node) phantom was made from a calibration device for NIRF and tissue-mimicking material. Serial dilutions of bevacizumab-800CW were made and ICG functioned as a reference. System settings, working distance, and thickness of tissue-mimicking material were varied to assess visibility of the fluorescence signal and tissue penetration. Tests were performed with four laparoscopes: VISERA ELITE II, Olympus; IMAGE1 S™ 4U Rubina, KARL STORZ; ENDOCAM Logic 4K platform, Richard Wolf; da Vinci Xi, Intuitive Surgical. (3) Results: The lowest visible bevacizumab-800CW concentration ranged between 13–850 nM (8–512 times diluted stock solution) for all laparoscopes, but the tracer was not visible through 0.8 cm of tissue in all systems. In contrast, ICG was still visible at a concentration of 0.4 nM (16,384 times diluted) and through 1.6–2.4 cm of tissue. Visibility and tissue penetration generally improved with a reduced working distance and manually adjusted system settings. (4) Conclusion: Depending on the application, bevacizumab-800CW might be sufficiently visible with current laparoscopes, but optimisation would widen applicability of tumour-targeted IRDye800CW tracers.

Background: Colon cancer (CC) is primarily treated with segmental resection, a surgical procedure associated with high morbidity and potential mortality. Sentinel lymph node (SLN) biopsy using the near-infrared fluorescence (NIRF) tracer indocyanine green (ICG) may help mitigate these risks by enabling organ-preserving surgery without the need for an anastomosis. It is hypothesized that contrast-enhancing software for NIRF could further improve SLN detection. Methods: This retrospective study evaluated whether a contrast-enhanced NIRF view improved SLN detection compared to the standard NIRF view of the robotic surgical system (da Vinci Xi). The contrast-enhanced view was generated using surgical image analysis software (PerfusionWorks), which enhances NIRF visual contrast. A retrospective analysis was conducted using intraoperative videos from SLN mapping with ICG in 10 patients with CC. Fifteen clinicians with varying levels of experience annotated video clips using both the standard and the contrast-enhanced views (44 clips per clinician in total). The sensitivity, specificity, accuracy, time-to-detection, and confidence scores were compared between the two views. Results: The contrast-enhanced view significantly improved sensitivity (49.3% to 62.4%, p < 0.001) and accuracy (46.1% to 51.8%, p < 0.001) compared to the standard view, with a decrease in specificity that was not statistically significant (39.4% to 30.4%, p = 0.08). On a 6-point Likert scale, clinicians reported higher confidence in their annotations with the contrast-enhanced view (median 5 vs. 4, p < 0.001). Conclusion: The contrast-enhancing software improved SLN detection in this test setting, improving sensitivity and accuracy. These findings support further investigation of its application in an intraoperative setting.