Dr. Ragaz said that while he believes the IHC4 has potential, it has not been prospectively validated as a predictor of benefit from chemotherapy.
And Dr. Simon D.H. Holt, who presented a favorable cost-effectiveness analysis of the Oncotype DX assay in clinical practice in the United Kingdom, cautioned that Ki-67 assay results vary considerably between laboratories.
"There are problems with Ki-67. One of the great advantages of Oncotype DX is its central laboratory with extremely tight quality assurance. It’s very repeatable. At the moment, in my opinion, it’s certainly the best thing on the market," said Dr. Holt of Prince Philip Hospital in Llanelli, Wales.
Genomic Health supported the study. Dr Ragaz, Dr. Smith, and Dr. Holt declared having no relevant financial relationships.