Stroma fallacy.

Arguing for bigger excisions to avoid tumor cells extending to the margin may be misconstruing the reason positive margins are bad in the first place. Two gene expression signatures known to confer stromal invasion were retrospectively run on over 6300 prostatectomy specimens. As feared, they were correlated with higher Gleason and Decipher scores and with more than double the risk of developing mets. But it’s not all bad news. Stromal expression was also associated with decreased DNA repair genes and thus increased benefit from postoperative radiation. In fact, interactions tests demonstrated a significant prolongation of mets-free survival with postop radiation among men with high stromal infiltration gene expression but not among men without such expression. TBL: High gene expression of stromal infiltration markers not only prognosticates prostate cancer badness but also predicts a benefit with the addition of postop radiation. | Mahal, Cancer 2020