Why does LNG IUS decrease endometrial and cervical cancer?

It does NOT decrease cervical cancer. It DOES decrease endometrial and ovarian cancer though for the latter not as much as ring/patch/pill. Endometrial cancer by stopping the monthly ebb and flow of the endometrial lining. Less growth/shedding, less risk of cancer. Ovarian cancer b/c it does block ovulation but not as 100% as the ring/patch/pill. again, less frequent damage to the ovary (ovulation) and less risk of CA.