Early tumor shrinkage of 10% or more after systemic therapy for metastatic renal cell carcinoma (mRCC) predicts superior outcomes, according to a new study.
Viktor Grünwald, MD, of Hannover Medical School in Hannover, Germany, and colleagues analyzed retrospective data from 4,334 patients with mRCC who participated in phase 2 and 3 clinical trials from 2003 to 2013. The investigators assessed early tumor shrinkage based on the percentage change in sum of the longest diameters of target lesions at the first post-baseline scan.
Dr Grünwald’s team determined that the optimal tumor shrinkage threshold for predicting overall and progression-free survival was 10%.
Median survival and time to progression were 28.5 months and 10.5 months, respectively for patients with 10% or greater tumor shrinkage compared with 16 months and 5.3 months, respectively, for those with less shrinkage, the researchers reported online in European Urology.
Patients who had early tumor shrinkage of 10% or more had a 38.5% decreased risk of death and 37.2% decreased risk of progression compared with patients who experienced less than 10% tumor shrinkage.
The authors concluded that early tumor shrinkage of at least 10% at the first post-baseline assessment “could serve as a putative early end point in patients with mRCC.”