Evaluation of the surgical learning curve for I-125 episcleral plaque placement for the treatment of posterior uveal melanoma: a two decade review

Purpose: To evaluate the surgical learning curve in episceral plaque brachytherapy placement in the management of posterior uveal melanoma.

Methods: A retrospective chart review of two cohorts of 250 consecutive patients undergoing plaque placement for posterior uveal melanoma from 2002 to 2004 and from 2008 to 2009 was conducted. The plaque-tumor apposition rates verified by intraoperative echography were evaluated and correlated with surgical volume over a 19-year period.

Results: In an initial study of 29 consecutive patients undergoing plaque placement from January 1992 to January 1995, a suboptimal plaque placement rate of 21% (n = 29) was identified. This percentage declined to 12% (n = 100) from January 2002 to January 2004, and further declined to 4% (n = 150) from June 2008 to August 2009. The tumor-plaque apposition rates for these three groups were 79% (1992-1995), 88% (2002-2004), and 96% (2008-2009). An estimated surgical volume of 1275 cases was performed to achieve a >90% precision rate for first application of primary plaque centration.

Conclusion: There are challenges to mastering the precise placement of radioactive plaques for posterior uveal melanoma. We have demonstrated a significant learning curve for plaque placement techniques, and have emphasized the importance of intraoperative ultrasound in the verification of plaque placement, thus allowing for intraoperative repositioning.