Your Beyond-the-Basics Guide to Endometrial Cancer Staging

by Sheila M. Eldred Health Writer

If you or a loved one has been diagnosed with endometrial cancer, you probably have dozens of questions. But the most pressing one is likely this: How advanced is it? Your cancer stage is designed to answer that question.

You may already know that the staging number refers to how far the cancer has spread: the higher the number, the further its reach. It also help determine the course of your treatment.

If that’s the extent of your knowledge on the topic, no worries. We talked to Jamie Bakkum-Gamez, M.D., a gynecologic oncologist at the Mayo Clinic in Rochester, MN, to get acquainted with some beyond-the-basics facts about stages of endometrial cancer.

woman looking at chart on computer

Get to Know the FIGO System

The International Federation of Gynecology and Obstetrics (FIGO) and the American Joint Committee on Cancer use a similar system for staging endometrial cancer. At its most basic level, there are four stages that are assessed using these factors:

  • T describes how far the main (primary) tumor has grown into the cervix and whether it has grown into nearby tissues.
  • N indicates any cancer spread to lymph nodes near the cervix.
  • M indicates if the cancer has spread (metastasized) to distant sites.

There are even more subcategories too. Most of the time, Dr. Bakkum-Gamez says, your doc will probably just give you your numbered stage (i.e. stage 1) because it’s easier to understand.

operating tools on table with surgeons in background

The First Step of Staging Is Done Through Surgery

Removing the uterus, fallopian tubes, and ovaries (called a hysterectomy) provides a window into the depth of the invasion and the size of the tumor. “Hysterectomy gives us all sorts of info about primary tumor,” Dr. Bakkum-Gamez explains.

Doctors can also see other important factors during surgery, including whether the lymphovascular space has been affected. (Don’t worry: We’ll explain what that is in a sec!).

Lymph node section under the microscope

Your Doc Will Also Check Your Lymph Nodes

Because endometrial cancer sometimes spreads to lymph nodes, it’s helpful to determine the location and number of those affected. In the past, doctors would randomly select which lymph nodes to remove and test. That often resulted in more being removed than necessary as well as some serious side effects, including lymphedema, or severe swelling in the legs, according to the American Cancer Society. Fortunately, newer methods can be more targeted and less invasive than previous techniques.

biopsy on microscope slides

A Sentinel Lymph Node Biopsy Can Help

This type of biopsy allows your surgeon to identify the first lymph node to which cancer is most likely to spread. Your doctor injects a radioactive substance and/or a blue dye near the tumor and follows its path using a special camera. Once the sentinel node is found, your doctor can remove just that one for testing. It’s much more precise than the older practice, and it helps avoid the side effects of a full lymphadenectomy, Dr. Bakkum-Gamez says. Plus, it allows the pathologist to do something called ultrastaging (more on that next).

hands in gloves using microscope

Ultrastaging is Uber-precise (But Not Everyone Agrees That's a Good Thing)

Because sentinel lymph node biopsy reduces the number of lymph nodes that pathologists need to look at, they can take a more in-depth look at each one, Dr. Bakkum-Gamez explains (thus, the term ultrastaging).

What can they find? Isolated tumor cells. This is a newer area of discovery the benefits of which are not yet fully understood. Doctors are still questioning whether finding a few isolated tumor cells (or even just one) in a lymph node should have the same impact on treatment as finding many more, Dr. Bakkum-Gamez says. “That’s the new debate: What do isolated tumor cells mean?”

doctors debating

How Doctors Are Dealing with Isolated Tumor Cells

In other words, if just a few isolated tumor cells are found in a lymph node, should the cancer be considered stage 3, because it technically may have spread to that location, meeting the guidelines for that stage? There’s just not yet enough follow-up evidence to know for sure, and different clinics and institutions treat it differently.

The Mayo Clinic, for example, calls this scenario “stage 1 with isolated tumor cells,” and treatment would follow stage 1 guidelines.

doctor talking to patient and her husband after surgery

When You’ll Find Out Your Staging

As soon as patients wake up from surgery, Dr. Bakkum-Gamez shares what the cancer stage is likely to be. (The less waiting the better.)

The tissue removed during the procedure gets processed, and then the final pathologist confirms the diagnosis in a couple of days.

“I usually tell patients there’s a 98% change there will be no change in the pathology report,” she says.

medical professionals sitting together and talking

You’ll Have a Team Behind You and Your Staging

Best practice calls for a multidisciplinary team (meaning doctors with different specialties) to stage and treat endometrial cancer.

At Mayo, for example, cases of patients with isolated tumor cells are reviewed by a tumor board, a group of gynecologic oncologists, pathologists, radiologists, and others who review all the patient’s slides, looking for a micrometastasis (a cluster of cancer cells spread via the lymphovascular system). If anyone finds a larger group of cancerous cells, then the cancer would be treated as stage 3, meaning the patient would receive chemo and radiation therapy.

Carcinoma of endometrium bio sample under microscope

Staging Isn't the Only Factor Determining Treatment

There are some factors that aren’t part of endometrial cancer staging that still impact your treatment plan. Lymphovascular space inversion (LVSI) is one of them. Here’s how Dr. Bakkum-Gamez explains LVSI to her patients:

“It’s when tumor cells migrate into the lymphatic vessels in the uterus that connect up with the vessels that lead to the lymph nodes,” she says. “Basically, it suggests that the tumor may be trying to metastasize to the lymph nodes.”

LVSI is an important risk factor for recurrence when it’s found at the top of the vagina. So treatment may include a short course of radiation, even if the cancer is determined to be stage 1, she says.

patient talking to her doctor

Deep Breath: You Can Do This

Remember, these are the basics: Cancer staging is a complicated business full of nuance and technical jargon that can be overwhelming. That’s why it’s important to use your health care team as a resource. When things get confusing, don’t be afraid to ask questions and see if your doctor can break things down into terms that are easier to understand. Together, you and your team of doctors and other health care professionals will help determine the best way to treat your endometrial cancer moving forward.

Sheila M. Eldred
Meet Our Writer
Sheila M. Eldred

Sheila Mulrooney Eldred is a graduate of Columbia’s School of Journalism and a former newspaper reporter. As a freelance health journalist, she writes about everything from life-threatening diseases to elite athletes. Her stories have appeared in The New York Times, Nature, FiveThirtyEight, Pacific Standard, STAT News, and other publications. In her spare time, she and her family love running, cross-country skiing, and mountain biking in Minneapolis.