DR GONZALEZ-ANGULO: There’s actually one study that has been prospectively completed called CONVERTHER done by GEICAM in Spain. And part of the trial was actually presented in San Antonio this year.
So we’ve done a couple of retrospective studies looking into these, and we’ve seen that for the hormone receptors the discordance rate can go up to 25 percent from primary to met, either going from positive to negative, negative to positive. HER2 is a little bit more reliable. And if it’s done in a centralized lab, it tends to be probably less than five percent. And these numbers are actually from CONVERTHER, which was a prospective study in which basically patients that were newly diagnosed with metastatic breast cancer — they did a core biopsy, they went back and took the block and repeated the ER, PR, and HER2.
What was interesting about this was that if the ER, PR and HER2 was repeated in the local hospital, the rates of discordance, for example, for HER2, went up to almost 20 percent. However, when all the blocks were sent to a university lab and everything was done in the central lab, the rate of discordance for HER2 was less than five percent.