New study results on origins of recurrences

ChiSandy

Relapses & Mets genomically linked to original primary tumors

Yesterday's Genome Web newsletter reported on a study published yesterday in Cancer Cell that may have contradicted a prior hypothesis that breast cancer metastases were probably “seeded" long before diagnosis & treatment of the original primary tumors. The study found that upon genomic analysis of both locoregional and distant recurrences, and then comparison with the genomic analysis of the primary tumors performed shortly after diagnosis, the recurrences shared many of the same genetic mutations with the original tumors. This suggests that metastasis or even locoregional recurrence arises relatively late in the game, in the “later stages" of development of the primary tumor.

Two caveats: the study did not address the genomic relationship between early-stage primary tumors and recurrences—it apparently focused on original primary "later-stage" tumors (and did not specify the definition of “later-stage"); and concentrated on metastatic and ipsilateral locoregional recurrence—it also did not mention contralateral “recurrences" (which are usually primary tumors themselves).

Another incidental finding was discovery of new (hitherto unidentified) mutations, which could be useful not just for genetic testing going forward but also for possible new forms of treatment.