Background:

The dual technique with radio colloid and blue dye is the gold standard in sentinel lymph node biopsy (SLNB) to stage axilla in breast cancer. However due to cost & infrastructural demands of nuclear medicine department most of the oncology centers are not doing slnb or are doing SLNB with blue dye which is not a standard of care. Indocyanine green (ICG) has recently been used as a method of identifying sentinel lymph nodes. Studies have shown that ICG fluorescence imaging alone or in combination with the blue dye method or the radionuclide method is a safe and easy technique. The objective of the present study was to assess the diagnostic performance of sentinel lymph node (SLN) biopsy using the indocyanine green (ICG) fluorescence method compared with that using the conventional method in detection of sentinel lymph nodes.

Material & Methods:

60 patients diagnosed with early breast cancer underwent the SLNB procedure using technetium-99m radio colloid (R), methylene blue dye (MB), and ICG. Fluorescence imaging was done using an indigenously designed , very economical fluorescence imaging system, Irilic.nm fluorescence imaging along with Indocyanine green. All SLNs that were removed during surgery were labelled as hot, blue or/and fluorescent and sent for pathological examination. The detection rate of SLNs and positive SLNs, and the number of SLNs of ICG, MB+ R, ICG + MB, ICG + R were compared. Injection safety of ICG and MB was evaluated.

Results:

Sentinel Lymph Node was identified in all 60 cases. Total Sentinel lymph nodes removed was 145 (Mean=2, Range 2-5), ICG was able to identify more nodes than the dual dye technique. The identification rate with the dual dye technique was 95%, with blue dye alone 93.6% and with radioisotope alone 96.8% whereas with ICG alone was 100%, with ICG + MB was 96.6% & ICG + R was 96.6 %. 28(46.6%) out of 60 patients had positive nodes which was identified by both dual dye & ICG. None of the patients had any local or systemic reaction with ICG, 3 patients with blue dye had tattooing & staining of skin.

Conclusion:

ICG is as effective as the dual dye for SLNB. ICG is safe & reliable. In addition, as a near-infrared dye, it has the advantages of real-time visualization, lower cost, and wider availability. It can be a boon for developing countries & second tier referral centers of developed country where there is limited access to nuclear medicine department & radiocolloid and even if its accesible the cost involved is too high which comes with added radiation exposure to medical personnel handling them. A combination of blue dye and ICG is useful dual approach when radioisotope is unavailable.

ICG verus Conventional Dye Clinical Profile

  ICG Radio-colloid+ B;ue Dye 
Detection Rate 100% 95% 
Sensitivity 100% (CI 83.16% to 100.00%) 100% (CI 83.16% to 100.00%) 
Positive Predictive Value 100% 100% 
Accuracy 100% 100% 
  ICG Radio-colloid+ B;ue Dye 
Detection Rate 100% 95% 
Sensitivity 100% (CI 83.16% to 100.00%) 100% (CI 83.16% to 100.00%) 
Positive Predictive Value 100% 100% 
Accuracy 100% 100% 

Citation Format: Somashekhar S, Rohit Kumar C, Zaveri S, Rajgopal A, Rakshit S, Ali SH. A prospective two arm comparative study of indo-cyanine green (ICG) enhanced fluorescence imaging vs conventional methods (blue dye and radiocolloid/hand held gamma probe) for sentinel lymph node detection in breast cancer - Going beyond the horizon [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-40.