Ex vivo indocyanine green fluorescence imaging for the detection of lymph node involvement in advanced‐stage ovarian cancer

Abstract

Background and objectives The aim of this study was to evaluate the role of indocyanine green (ICG) fluorescence imaging (FI) for the ex vivo detection of metastatic lymph nodes (LNs) in advanced stage ovarian cancer (AOC). Methods Paraffin‐embedded LNs from patients included in a previous ICG‐FI study (Protocol NCT01834469) were further assessed for fluorescence. Intravenous injection of ICG was delivered intraoperatively. Tumor‐to‐background ratios (TBRs) were calculated. Results A total of 675 LNs from 19 patients were analyzed. The mean LN number per patient was 29.3 (median: 24; range 2‐77). Seventy‐three LNs were malignant (10.8%), 602 were benign (89.2%). The mean TBR of all LNs was 1.5 (SD 0.8). With a cut‐off TBR of 1.3, the sensitivity, specificity, positive predictive, and negative predictive values of ICG‐FI for retroperitoneal LNs were 80%, 41%, 2.8%, and 99%, respectively. On univariate analysis, only the fluorescence ratio (TBR ≥ 1.3) was correlated with malignancy at pathology (P = 0.03). No predictive factors of pathological LN status were found on multivariate analysis. Conclusions Ex vivo ICG‐FI of retroperitoneal LNs in AOC had good sensitivity but poor specificity. However, its high negative predictive value could make it an appropriate complementary tool to focus pathological analysis on fluorescent LNs.

Near-Infrared Fluorescence Imaging of Breast Cancer and Axillary Lymph Nodes After Intravenous Injection of Free Indocyanine Green

“…in patients who underwent lymphadenectomy for the nodal relapse of head and neck cancer ( 53 ). Our group confirmed their observation in 2016 in a series of 11 patients who had undergone cervical lymphadenectomy for primary and relapsing head and neck cancer ( 54 ) but also reported such accumulation of ICG in metastatic LNs in cases of colorectal and ovarian cancer ( 55 – 57 ).…”

Absence of residual fluorescence in the surgical bed at near-infrared fluorescence imaging predicts negative margins at final pathology in patients treated with breast-conserving surgery for breast cancer

“…Second, timing is a major concern when using ICG-FI for tumoral detection and the best interval between ICG IV injection and imaging remains to be defined. In our study, the median time observed between ICG injection and the resection of the operative specimen was 46 min, corresponding to the optimal delay for ICG-FI reported in the literature in breast tumors and other oncological conditions [13e15, 18,20,34]. Third, the imaging system used in our study, which does not have an appropriated sized camera head for tumor bed exploration and does not allow dual imaging (combined view) with white light in color and NIR, which should rule out the background noise issues.…”

“…For objective fluorescence intensity calculation, we used, as reported in our previous studies, a semi-quantitative analysis of the fluorescence intensity using signal-to-background fluorescence ratio (SBR) on intraoperative recorded videos and tumor to background ratio (TBR) on videos recorded in the pathology department. These images were correlated with the final anatomoepathological reports [13,18,20].…”

“…SBRs of the tumor bed were analyzed as continuous and categorical variables using a cut-off of 1.3 (<1.3/ 1.3). The cut-off threshold value of 1.3 was determined like in our previous studies as it represents the threshold value with the best agreement between the clinical and the quantitative scale [13,18,20]. Univariate analysis of fluorescence intensity (TBR) of clinical and pathological tumor characteristics for the primary breast tumors was performed.…”

Optical molecular imaging can differentiate metastatic from benign lymph nodes in head and neck cancer

“…To improve nodal yield and to increase detection of small LNs, fat clearance can be performed 19 , but this technique requires a chemical agent to dissolve the fat tissue around the LNs, and thus is time consuming, expensive and potentially hazardous. Local or intravenous/intra-arterial injections of methylene blue and indocyanine green have been used to improve LN identification at pathology, but due to poor tumor specificity this has never become routinely implemented; sensitivities and specificities achieved with this approach vary between 52–94% and 76–78%, respectively 20–22 . Most importantly, none of the current techniques discriminates between metastatic LNs and benign LNs.…”