Methylene blue for one-stage sentinel lymph node biopsy

Research performed at:

1. the Departments of Surgery and Radiology, Louisiana State University Health Sciences Center, New Orleans LA.

2.Iso-Tex, Friendswood, TX and General Electric Health Care New Orleans, LA.

The authors:

Jason David Cundiff, Yi-Zarn Wang, Gregory Espenan, Thomas Maloney, Arthur Camp, Laura Lazarus, Alan Stolier, Randy Brooks, Bruce Torrance ,Shawn Stafford, James P. O’Leary, Eugene A. Woltering.

Sentinel lymph node biopsy can be associated with delays in operating room schedule and with significant pain during the preoperative 99m Tc colloid injection. To avoid these problems, we developed a novel radiolabeled blue dye that can be injected intraoperatively.

We performed a phase I/II trial (IND#70627) of sterile pyrogen-free 125 I-methylene blue to identify sentinel nodes in patients with breast cancer. Twelve women were studied. Two women each were given peritumoral or circumareolar injections of 100, 200, 300, 400, 500, or 1000 Ci of 125 I methylene blue.

Sentinel nodes were detected in 11 of 12 patients, with a low-dose 200 Ci patient being the single exception. The number of sentinel nodes detected per patient ranged from 0 to 3 (mean  1.66 nodes/case). Radioactivity at the tumor injection site counts per second (cps) averaged over 10 seconds ranged from 3346 to 47,300 cps and was highly dose-dependent (r 0.90, P 0.0002). In contrast, the in vivo node counts ranged from 0 to 1228 cps, while ex vivo counts ranged from 0 to 1516 cps. The in vivo nodal counts were dose dependent (r 0.67, and P 0.0231). Radiation was carefully monitored inside the operating room and in pathology. Even with the 1-mCi dose, the radioactive blue dye produced significantly lower personnel exposure than historically seen with 99m Tc. Conclusions: This method eliminates the painful preoperative injections of 99m Tc colloid, is performed by the surgeon in the operating room, is associated with lower radiation exposures for personnel, and avoids the delays caused by non-operating room personnel. These observations warrant a more extensive trial of this method using the 1000-Ci dose of 125 I methylene blue dye for sentinel lymph node biopsies.