552 Background: Use of multi-gene real-time PCR (RT-PCR) based assays e.g. Recurrence Score (RS) and single markers (grade, uPA/PAI-1, ER/PR, HER2, KI-67) is currently controversially discussed in early BC. Here, we present the final WSG-planB trial correlation analysis of risk assessment tools and first prospective comparison of independent central pathology IHC/FISH assessment and RT-PCR for single markers. Methods: Plan B trial (n=2,448 randomized for 6xTC vs. 4xEC-4xDOC in locally HER2- BC). RS has been used as selection criterion for cht omission in HR+ BC (if RS<11 in pN0 or pN1). uPA/PAI-1 was optionally obtained. Grade, ER/PR, HER2 (IHC/FISH), Ki-67 were evaluated by the independent trial pathologist in all tumors. Results: From 04/09 to 11/11, 3196 patients have been recruited and 2448 randomized. RS distribution in 2551 HR+ tumors: 0-11 (18%), 12-25 (60%), >25 (22%). In 354 pN0-1 patients, cht was omitted based on low risk RS (88% compliance). Central grade for n=3038 and IHC/FISH results are currently available in n=1476. Moderately significant correlations were only found between RS and both central grade (rs=0.313; p<0.001) as well as Ki-67 (rs=0.374; p<0.001) and a weak one for uPA/PAI-1, particularly due to poor correlations within the RS group <26. In 1476 locally HER2- cases, n=9 were found as 3+ and/or FISH+ by central analysis. In 6 HR+/HER2+ cases, RS revealed 2 positive, 2 equivocal and 2 negative results. In 7 cases positive for HER2 by RT-PCR central pathology revealed 4 negative results. 24 locally HR+ cases are assessed as HR- in central pathology (2%). Among these, 6 were ER positive by RT-PCR. Final correlation analyses will be presented at the meeting. Conclusions: These first prospective data demonstrate that high-risk status according to RS is predictive of high risk by other factors, but the converse is not true. Regarding controversial HER2 and HR status by RT-PCR and IHC/FISH, we found few cases with false-negative or positive RT-PCR results in HER2- BC by local pathology. However, these discrepancies could potentially have a substantial impact on clinical patient management.
P178 Prospective comparison of uPA/PAI-1, Ki-67 based molecular classification, Recurrence Score and clinical–pathological characteristics in hormone-receptor (HR) positive primary breast cancer: Pilot phase of the randomized WSG PlanB trial
