Abstract P1-01-18: Sentinel lymph node identifcation in breast cancer using methylene blue and patent blue: A randomized controlled trial
Authors: Vuthaluru S , Srivastava A , Misra M 
Published: August 2014

Background: Sentinel lymph node biopsy (SLNB) is the standard of care for management of axilla in West. However, In India few centres have established SLN program for breast cancer. The main reason is non- availability & high cost of commercial blue dye & gamma probe. Methylene blue (MB) is not recommended for SLNB in West. The biochemical reason attributed for MB not being useful for SLNB has been its inability to bind to plasma proteins. However, Sutton has demonstrated the ability of MB in reducing the glutathione sulphhydryl group by nucleophilic additive mechanism that may explain the success of MB in identifying SLN I in few case series from third world .However, there is no RCT comparing SLN identification using MB and patent blue violet (PBV) till date.

Aim:To compare the sentinel node (SN) identification rate using patent blue violet (PBV) in combination with radiotracer versus methylene blue (MB) in combination with radiotracer in breast cancer.

Sample size: Assuming that MB identified SN in 75% of cases and PBV in 85% of cases, a two group continuity corrected X2 test with 0.05 two sided test will have 80% power to detect the difference when the sample size is 107.

Materials and Methods: Clinically axillary lymph node negative (N0) patients with breast cancer with tumor (T) stage T1, T2; T3 and T4b were included in the study. T3 and T4b patients received NACT. Patients with palpable hard axillary lymph node, cytologically positive lymph node, stage IV diseae and thoses with previous history of surgery, radiation therapy to axila were excluded from the study. SLNB was performed using combination technique. TC99 sufur colloid was injected at periareolar site intradermally in all patients. Technique of blue dye injection was as follows- 4 ml of 1% PBV: 1 ml intradermal over the tumor, 0.5 ml at 12, 3, 6 and 9 o clock position intraparenchymal around the tumor and 1 ml subareolar. In the MB group, 4 ml of 1% MB was injected at same sites as above.The site of intradermal injection was included in the skin incision. The excised SLN were sent for frozen section and imprint cytology. If SLN was negative for metastasis, only SLNB was performed as surgical treatment of axilla.

Results: Between Jan 2010- Jan 2013, 227 of 232 eligible patients (115 in MB arm & 112 in PBV arm) with primary breast cancer with clinically negative axilla consenting to take part in the study were enrolled. T status: T1: 48; T2:126; LABC: 37, Tx: 6. SLN was identified in 215/227 pts (95%). SLN was negative in 133 (62%). All SLN +ve patients (82; (38%) underwent ALND. Among those with positive SLN, SLN was the only positive node in 24 (29%) patients and rest had non sentinel nodes involvement (58; 71%). SLN identification rate using MB (107/112) in combination with Tc99 S Colloid was similar to that with PBV in combination with Tc99S colloid (108/115). Number of nodes harvested nodes (299 v/s 302), blue nodes (260v/s 261) and positive nodes (60 v/s 63) were similar in both groups.

Conclusion: MB can be used for SLB in breast cancer with similar identification & false negative rates as PBV in institutions where commercial blue dye and facilities for radiotracer guided technique are not available.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-01-18.