The stage of cancer endometrium with invasion of 10 mm of myometrium is:

According to older staging If tumor involves myometrium, it belongs to either stage Ib or Ic. Normal thickness of myometrium is 10-20 mm, therefore, if 10 mm of myometrium is involved. It should ideally be included in stage Ic but since Ic is not given in options, IInd best option is lb. Now if we think from newer revised staging it says In stage IA-Tumor is confined to uterus and either it is limited to endometrium or less than half of myometrium is involved. Stage IB-Tumor confined to uterus with more than or equal to half of myometrial invasion Thickness of 10 mm means more than half of myometrium, i.e. stage lb.