Implementation of Indocyanine Green to Identify Sentinel Lymph Nodes During Surgery for Breast Cancer

Background:

Breast cancer affects one in seven women. Detecting lymph node metastases via the sentinel lymph node biopsy (SLNB) is crucial for prognosis and treatment. The gold standard is radio-guided surgery using the radioisotope technetium-labeled (99mTc)-nanocolloid, which requires preoperative injection and lymphoscintigraphy. However, the use of 99mTc poses significant burdens on patients, as it requires additional hospital visits or travel to another hospital due to the limited availability of nuclear medicine facilities. The use of 99mTc also creates logistical challenges and lacks sustainability. A recently proven, equally effective and safe alternative method is peroperative real-time fluorescence imaging using Indocyanine Green (ICG). ICG offers many advantages over 99mTc for patients, healthcare providers, and society. Yet, the use of ICG for SLNB remains limited, as hospitals face challenges due to uncertainty in transitioning and limited familiarity with recent findings. Implementation guidance is imperative for effective adoption, to avert further practice variation and to ensure patients benefit from this evidence-based alternative method.

Objectives:

The INFINITE trial aims to successfully implement ICG-fluorescence for identifying the sentinel lymph node by guiding the implementation process using the Effective Implementation of Change model developed by Grol and Wensing, identifying and understanding the factors influencing implementation outcomes through the Consolidated Framework for Implementation Research, evaluating the outcomes of implementation efforts using a mixed-methods approach and the outcomes framework proposed by Proctor et al., and creating conditions for nationwide implementation. Secondary aims are to develop a uniform medical protocol for the use of ICG for SLNB, to develop an implementation guide that aligns with current practice, to prepare educational materials for surgeons and modules for the curriculum of surgical residents (CASH), to produce patient information materials and organize interactive meetings for surgical healthcare providers and their teams, to further substantiate the effectiveness, safety, and cost-effectiveness of ICG, to increase support and a sense of urgency for ICG implementation by organizing informational sessions during annual conferences of the relevant scientific associations, and to facilitate nationwide scale-up by incorporating ICG into SLNB guidelines.

Study Design:

ICG will be implemented in seven strategically chosen Dutch hospitals during the INFINITE trial. These hospitals have been selected to represent different areas, settings, and sizes, ensuring broad applicability and support for subsequent nationwide implementation. The INFINITE trial is a multicenter hybrid effectiveness-implementation study using a stepped-wedge cluster trial design across three phases: Phase I, pre-implementation (99mTc only); Phase II, transition period (99mTc and ICG); and Phase III, post-implementation (ICG only). Based on site readiness and in consultation with the participating centers, three clusters will be formed, each consisting of two or three hospitals. Clusters will transition to the next phase at fixed intervals, creating an iterative learning cycle. This approach allows for regular evaluations of the implementation strategies, processes, and products, including the protocol, implementation guide, educational materials, and patient information. Process evaluations will inform adjustments using the ERIC-CFIR matching tool, ensuring rapid integration of lessons learned to enhance implementation in the next cluster.

Intervention:

In Phase I, pre-implementation, SLNB is performed using standard care with 99mTc injection and lymphoscintigraphy the day or morning before surgery, followed by radio-guided surgery with a gamma-detection probe. In Phase II, the transition period, SLNB is performed using both ICG and 99mTc. Patients receive 99mTc injection and lymphoscintigraphy before surgery, with the surgeon blinded to the imaging results. During surgery, after induction of general anesthesia and before axillary incision, 5 mg (2 ml) ICG is injected periareolarly, and SLNB is performed using fluorescence imaging. After excision of the sentinel lymph node(s), the standard gamma probe is used to test the excised nodes and the axilla for 99mTc activity, and the axilla is also explored by direct visualization and palpation. In Phase III, post-implementation, SLNB is performed using ICG as the sole tracer, with the same dosage and injection method, and the sentinel lymph node is visualized using fluorescence imaging and excised.

Outcomes:

Study endpoints are categorized into actual and anticipated implementation outcomes, client outcomes, and service outcomes. The primary endpoint is adoption, defined as the proportion of SLNB procedures conducted with ICG only, 99mTc only, or both during Phase III, compared to the total SLNBs in that phase, measured using screening logs and hospital records. All other outcomes are secondary. Fidelity, another actual implementation outcome, is measured through an intraoperative survey. Anticipated implementation outcomes such as appropriateness, feasibility, and acceptability are evaluated via a healthcare provider survey during Phase III. Client outcomes include patient satisfaction assessed through a post-procedure survey. Service outcomes encompass effectiveness, safety, cost-effectiveness, and the impact on necessary personnel, evaluated using perioperative and hospital administration data.

Risks and Burden:

Patients who consent will not experience any extra burden from ICG-fluorescence. ICG will be administered under general anesthesia, so patients will not experience additional discomfort, site visits, or procedures. ICG is non-ionizing and has very few reported complications or adverse events. Considering a maximum of two additional nodes sampled, the preferred anatomical location of these nodes, and the clinical experience with additional lymph node sampling, no increase in surgical morbidity is expected. Patients may benefit from the intervention as ICG can increase sentinel lymph node identification rates and eliminate the need for a preoperative visit to the Nuclear Medicine department for 99mTc injection. Completion of the patient satisfaction questionnaire will take approximately 10 to 15 minutes. Both risks and burden are therefore considered negligible.