# Indocyanine green versus technetium-99m for sentinel lymph node biopsy in breast cancer: the FLUORO trial

## TL;DR

This study compared indocyanine green and technetium-99m for lymph node mapping in breast cancer, finding similar effectiveness but potential cost savings with indocyanine green.

## Contribution

Demonstrated that indocyanine green fluorescence is a viable and potentially cost-effective alternative to technetium-99m for sentinel lymph node biopsy.

## Key findings

- ICG and 99mTc had similar sentinel lymph node identification rates (97.8% vs. 98.3%).
- ICG identified 95.2% of metastatic sentinel lymph nodes compared to 98.8% for 99mTc.
- Surgeons reported similar ease of use for ICG and 99mTc, with ICG potentially offering long-term cost savings.

## Abstract

Standard sentinel lymph node (SLN) mapping for early breast cancer involves technetium-99m (99mTc) lymphoscintigraphy. Indocyanine green (ICG) fluorescence allows real-time visualization of lymphatics and nodes while avoiding radiation exposure and the inconvenience of 99mTc, but its inclusion in international guidelines is not widespread. This study compared efficacy and costs between ICG and 99mTc for axillary SLN lymphatic mapping.

Patients with early breast cancer and clinically negative axilla who underwent lymphatic mapping with ICG and 99mTc were enrolled in a prospective single-institution single-arm non-randomized trial (2021–2024). Data on the number of SLNs, including metastatic nodes, rate of failed mapping, costs, and the surgeon’s reported ease of mapping with ICG compared with 99mTc were collected. Cost analysis used Medicare item numbers and microcosting.

A total of 305 patients were enrolled, with 637 SLNs sampled. The SLN identification rate was 97.8% (95% confidence interval (c.i.) 96.3 to 98.7%) for ICG and 98.3% (95% c.i. 96.9 to 99%) for 99mTc. The mean(standard deviation (s.d.)) number of SLNs identified with ICG and 99mTc was 2.06 (1.99) and 2.07 (2.02), respectively (P = 0.871). Metastatic SLNs were identified in 70 of 305 patients (23.0%), with 83 metastatic SLNs in total. ICG identified 79 of 83 metastatic SLNs (95.2%; 95% c.i. 88.3 to 98.1%) and 99mTc identified 82 of 83 metastatic SLNs (98.8%; 95% c.i. 93.5 to 99.8%; P = 0.256). Mean(s.d.) surgeon-reported ease for using ICG and 99mTc, rated used a five-point Likert scale, was 1.67 (0.98) (95% c.i. 1.56 to 1.78) and 1.5 (0.59) (95% c.i. 1.43 to 1.57), respectively (P = 0.082). 99mTc cost an additional EUR841 (95% c.i. EUR766 to EUR917) per patient but ICG would require > 35 patients before breaking even with initial outlay equipment costs.

ICG fluorescence performed similarly to 99mTc lymphoscintigraphy and may be less costly over the long term.

This prospective trial demonstrated that indocyanine green fluorescence performed similarly to technetium-99m lymphoscintigraphy and was potentially less costly in the long term for axillary sentinel lymph node biopsy in breast cancer.