Sentinel lymph node biopsy after neoadjuvant treatment of breast cancer using blue dye, radioisotope, and indocyanine green: Prospective cohort study

Background: The breast cancer treatment paradigm has shifted to neoadjuvant treatment. There are many advantages to neoadjuvant treatment, such as tumor downsizing, in vivo tumor biology testing, treating micrometastasis, and achieving complete pathological response (a surrogate marker for overall survival). However, in the post neoadjuvant settings, sentinel lymph node biopsy can be done using a dual staining technique to decrease the false-negative rate (FNR) and increase the detection rate. However, many hospitals are not equipped to use radioisotopes. Here we investigate the detection rate and accuracy of sentinel lymph node biopsy in post neoadjuvant treatment breast cancer, comparing radioisotope, isosulfan blue, and indocyanine green (ICG) approaches. Material and methods: This prospective study includes breast cancer patients (T2-4, N1-2) who had received neoadjuvant treatment. Carcinomas were confirmed by tissue pathology. Patients who had previous surgical biopsy or surgery involving the axillary regions, and those with a history of allergy to ICG, isosulfan blue, or radioisotope were excluded from the study. Result: The study was done between July 1, 2019 to March 31, 2020. The mean age of participants was 53 years. Fourteen (60.87%) were post-menopause, two (8.7%) were perimenopause, and seven (30.43%) were premenopause. The clinical-stage distribution of the participants was: 2A (8.7%), 2B (34.78%), 3A (43.48%), and 3B (13.04%). The primary tumor size was 4.82 +/- 2.73 cm. The lymph node size was 1.8 +/- 0.96 cm. The detection rates at the individual level were 95.23% with ICG, 85.71% with isosulfan blue, and 85.71% with a radioisotope. The detection rate increased up to 100% when the ICG and blue dye methods were combined. The FNRs of sentinel lymph node biopsy at the individual level were: 10% using ICG, 30% using isosulfan blue, and 40% using radioisotope. At the lymph node level, the detection rates were 93.22% using ICG, 81.78% using isosulfan blue, and 53.87% using a radioisotope. The FNRs of sentinel lymph node biopsy at the lymph node level were 19.05% with ICG, 21.43% with isosulfan blue, and 18.03% with a radioisotope. However, the FNR was less than 10% when ICG, isosulfan blue, and a radioisotope were combined. Conclusion: We can perform sentinel lymph node biopsy by combining blue dye with ICG as an optional modality and achieve a comparable outcome with combine radioisotope in locally advanced breast cancer after neoadjuvant treatment.