Abstract. The present study presents a novel near-infrared optical probe for the sentinel lymph node (SLN) detection in breast cancer patients, based on the recording of scattered photons. The aim of this study was to improve the detection of patent blue V (PBV), a dye routinely injected during clinical practice. A combined injection of the dye and radioactive colloid was used in the 24 patients enrolled in the study. The clinical results of the ex vivo detection of 70 dye-marked SLNs are reported, subsequent to the injection of various quantities of PBV (0.25-2 ml). The accuracy and success rate of an isotopic probe for the detection of radioactive colloid tracer, the eye visibility threshold of the surgeon and the use of a new optical probe were examined. The radio-labeled and dye-marked sentinel lymph nodes were all detected by the radio-isotopic probe, as opposed to the 75% detected by the eye visibility threshold of the surgeon. The optical probe detected all of the nodes, regardless of the volume of the dye injected. The relative PBV concentration computed by the probe facing SLNs with infravisible/visually undetectable dye-mark was relatively constant at 5.5±1.4 µmol/l. The optical detection of the sentinel lymph nodes using PBV and the probe presented in this study have the potential to reduce the false negative detection rate. This instrument is likely to provide surgeons with a simple diagnostic tool, without significantly changing their surgical procedures.
IntroductionIn France, approximately 40% of the newly diagnosed cancer in female patients is breast cancer. The mapping and excision of sentinel lymph nodes is the main minimally invasive technique for cancer staging. The morbidity associated with this technique is less compared to the axillary dissection (1). The procedure used in routine clinical practice is clearly defined. Combined blue dye and isotope injection in the periareolar area allows for the identification of the sentinel lymph node (SLN) at a higher success rate (2-4). Thus, the detection subsequent to skin incision in the armpit involves a nuclear probe. Blue dye, such as patent blue V (PBV), is used to provide visual guidance during the surgical procedure (5,6). Potential allergy to PBV dye has recently been thoroughly studied and severe anaphylaxis is rare, approximately 0.9% (7). However, this detection method involves an element of subjectivity and requires a learning curve on behalf of the surgeon (8).Currently, attempts have been made to develop accurate and minimally invasive diagnostic and interventional tools. Thus, several optical methods are currently being developed in parallel with conventional methods, such as magnetic resonance imaging (MRI) (9), positron emission tomography (PET) (10) or ultrasound (11), to detect SLN. The use of tracers with radiocolloid metastable technetium 99 ( 99m Tc) and fluorescent labeling (ICG) is widely suggested (12). Moreover, the photoacoustic approach using nanoparticules has increasingly been considered in several studies (13). However,...