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.