Histopathology of retinoblastoma: does standardization make a difference in reporting?

The International Retinoblastoma Staging Working Group (IRSWG) provided guidelines for tissue handling of eyes enucleated for retinoblastoma. We adopted these guidelines from January 2009. Reviewing histopathology slides between January 2006 and December 2010 we found significantly more number of eyes with massive choroidal, optic nerve, and anterior segment invasion by tumor cells in the post-IRSWG era. The guidelines provided by the IRSWG; in addition to being standardized; recognize more eyes with histopathologic risk factors compared to techniques applied in the past. This may translate to more children receiving adjuvant chemotherapy and contribute to reduced mortality rates in the future.