The holy grail would be fixing commonly occurring mutations that cause the cancer, but to my knowledge the edit/correction rate is too low for this to work curr

The holy grail would be fixing commonly occurring mutations that cause the cancer, but to my knowledge the edit/correction rate is too low for this to work currently, plus the possibility of causing more cancer by bad edits. Thus, the T-cell approaches are more promising currently as it allows for direct modification of cells to fight cancer with known anti-cancer antigens, using a modified immune system.