Endometrial Cancer Stages

Doctors use "stages" to describe how far cancer has grown and whether it has spread. Knowing the stage of your cancer helps your care team plan the best treatment and understand your prognosis.

Endometrial cancer is staged using the FIGO (International Federation of Gynecology and Obstetrics) staging system, which was updated in 2023 to incorporate molecular features alongside tumor size and spread. Staging is performed surgically, with the final stage determined after examination of the uterus, lymph nodes, and other tissue removed during surgery.

The FIGO Staging System

Stage I — Cancer confined to the uterus

• Stage IA: Cancer is confined to the endometrium (inner lining) or invades less than half of the myometrium (uterine muscle).

• Stage IB: Cancer invades half or more of the myometrium but has not spread outside the uterus.

• Stage IC: Cancer involves the uterine serosa (outer surface) or adnexa (ovaries or fallopian tubes).

Stage II — Cancer involves the cervix

Cancer has spread to the cervical stroma (supporting tissue of the cervix) but has not spread outside the uterus.

Stage III — Cancer has spread regionally

• Stage IIIA: Cancer has spread to the uterine serosa, ovaries, or fallopian tubes.

• Stage IIIB: Cancer has spread to the vagina or the parametrium (tissue that surrounds the uterus).

• Stage IIIC1: Cancer has spread to pelvic lymph nodes.

• Stage IIIC2: Cancer has spread to lymph nodes along the aorta (para-aortic lymph nodes).

Stage IV — Cancer has spread beyond the pelvis

• Stage IVA: Cancer has spread to the bladder or bowel mucosa.

• Stage IVB: Cancer has spread to distant organs such as the lungs, liver, or bones, or to inguinal (groin) lymph nodes.

Molecular risk classification

In addition to surgical stage, endometrial cancers are now classified into molecular risk groups that incorporate the TCGA molecular subtypes:

• POLE ultramutated. Excellent prognosis regardless of grade or stage

• Mismatch repair deficient (dMMR/MSI-H). Intermediate to favorable prognosis; responds well to immunotherapy

• No specific molecular profile (NSMP). Intermediate prognosis

• TP53 mutant/copy number high. Worst prognosis and includes most serous carcinomas.

Tumor grade

The grade describes how abnormal the cancer cells look under the microscope and how fast they are likely to grow:

• Grade 1 (well differentiated). Cells look mostly like normal endometrial cells. Lower grades tend to grow slowly.

• Grade 2 (moderately differentiated). Cells have features between grade 1 and grade 3.

• Grade 3 (poorly differentiated). Cells look very abnormal and tend to grow more aggressively.

Recurrent endometrial cancer

Endometrial cancer can return after initial treatment. Recurrences are classified by location:

• Local recurrence. Cancer returns at the top of the vagina (vaginal vault), where the uterus was removed.

• Regional recurrence. Cancer returns in the pelvic lymph nodes or surrounding tissues.

• Distant recurrence. Cancer returns at a distant site, most often the lungs, liver, or bones.

Your care team will work with you to determine the best next steps based on the timing and location of recurrence and the treatments you have already had.