Known traditional methods are imperfect, and perhaps predict cancer would be created due to misreplection of DNA. Would advancements in synthetic biology prevent this from happening by modifying cells to repair it naturally?
Well, cells already have machinery to repair DNA, and otherwise to enter apoptosis if it is beyond repair. But one hallmark of cancer is that the proteins in charge of those processes have mutated as well.
Perhaps modifying the cell to passively repair these proteins with an enzyme while modifying the machinery that repairs the DNA would be viable. Although I am truly not an expert on this subject.