Stage I endometrial cancer is diagnosed when cancer cells remain confined to the uterus, without spreading to nearby lymph nodes or distant organs. With around 95 percent of people surviving at least five years after diagnosis, this early stage offers an excellent prognosis. Understanding your treatment options, from surgery to supportive therapies, can help you navigate this journey with confidence.

Understanding Your Treatment Path: What Stage I Endometrial Cancer Means for You

When doctors diagnose stage I endometrial cancer, they are telling you that the disease has been caught at an early point. The cancer has developed in the endometrium, which is the inner lining of the uterus, and has not yet moved beyond the uterine walls. This is important news because early detection significantly improves the chances of successful treatment. About two-thirds of people with endometrial cancer are diagnosed at stage I or II, which means their cancer is still localized and has not spread to other parts of the body.^[1]

Treatment goals at this stage focus on removing the cancer completely, preventing it from returning, and preserving your quality of life as much as possible. The approach your medical team recommends will depend on several factors: how deeply the cancer has grown into the muscle wall of your uterus, how abnormal the cancer cells look under a microscope (called the grade), your age, your overall health, and whether you have other medical conditions. Some people may need only surgery, while others benefit from additional treatments afterward to reduce the risk of the cancer coming back.^[4]

Stage I is further divided into substages based on the cancer’s behavior and location. In stage IA, the tumor is either found only in the endometrium itself, or it has grown less than halfway into the myometrium (the muscular layer of the uterus), or it is non-aggressive and affects only the uterus and ovaries. Stage IB means the cancer has grown halfway or more into the muscle wall, but it remains within the uterus. Understanding these distinctions helps doctors decide which treatments are necessary.^[1]

There are established, proven treatments that medical societies around the world recommend for stage I endometrial cancer. These are based on decades of research and clinical experience. At the same time, scientists continue to explore new therapies through clinical trials. These studies test innovative drugs and approaches that may one day become standard options. If you are interested, your doctor can discuss whether a clinical trial might be suitable for you.

Standard Treatment: The Foundation of Care for Stage I Endometrial Cancer

Surgery is the cornerstone of treatment for stage I endometrial cancer. For most people, the first and most important step is a surgical procedure to remove the uterus and cervix, called a total hysterectomy. During the same operation, surgeons typically also remove both fallopian tubes and ovaries, a procedure known as bilateral salpingo-oophorectomy. Removing the ovaries is important because they produce hormones like estrogen that can sometimes fuel the growth of endometrial cancer. In some cases, particularly when the cancer is low-grade and confined to the inner lining, younger or premenopausal individuals who wish to preserve fertility may discuss alternatives with their doctor, though this is not the standard approach and carries risks.^[4][11]

During surgery, doctors also perform what is called surgical staging. This means they carefully examine the tissue removed and sometimes take samples of nearby lymph nodes to check for cancer cells. A sentinel lymph node biopsy is a technique where the surgeon identifies and removes just a few key lymph nodes that are most likely to show whether cancer has spread. This approach is less invasive than removing all the lymph nodes in the pelvis and can reduce side effects like swelling. If the lymph nodes are free of cancer, it confirms that the disease is truly confined to the uterus.^[4][11]

The type of surgery you have may vary. Many surgeons now use minimally invasive techniques, such as laparoscopy or robotic-assisted surgery, which involve smaller incisions and typically lead to faster recovery times compared to traditional open surgery. However, the choice depends on your specific situation, the surgeon’s expertise, and the characteristics of your cancer. If you are not able to undergo surgery due to other serious health conditions, your doctor may recommend radiation therapy or hormone therapy as an alternative.^[4]

After surgery, some people require additional treatment, called adjuvant therapy, to lower the chance of the cancer returning. Whether you need this depends on your risk level, which is determined by the grade of the cancer (how abnormal the cells look), how deeply it invaded the muscle wall, and other factors. People with very early, low-risk disease—such as stage IA, grade 1 or 2 cancer—often do not need any further treatment after surgery. Their five-year survival rates are excellent, and close monitoring is usually sufficient.^[4][11]

For those with intermediate risk, doctors may recommend brachytherapy, a type of internal radiation therapy. This involves placing a radioactive source inside the vagina for a short time to kill any remaining cancer cells in that area. The treatment is usually given in a few sessions over several weeks. For people with high-intermediate or high-risk stage I disease—such as stage IB with grade 3 cancer—the options may include external radiation therapy (where beams of radiation are directed at the pelvis from outside the body), chemotherapy, or a combination of both. External radiation therapy typically involves daily sessions over several weeks.^[4][11]

Chemotherapy uses anti-cancer drugs to destroy cancer cells throughout the body. The most common combination for endometrial cancer is carboplatin and paclitaxel. These drugs are usually given through an intravenous (IV) line in cycles, with rest periods in between to allow your body to recover. Chemotherapy is particularly important for people with aggressive types of cancer, such as carcinosarcoma, or for those whose cancer has certain molecular characteristics that make it more likely to return.^[11]

Hormone therapy is another option, especially for low-grade cancers or for people who cannot have surgery or radiation. This treatment uses medications called progestins, which are synthetic versions of the hormone progesterone. These drugs can slow or stop the growth of some endometrial cancers. Hormone therapy may be given as pills or through an intrauterine device (IUD) that releases the medication directly into the uterus. This approach is sometimes considered for young people who want to preserve their ability to have children, though it requires careful monitoring with regular biopsies to ensure the cancer is responding.^[4][13]

Side effects of treatment vary depending on the approach. Surgery can cause pain, fatigue, and changes in bowel or bladder function. Removing the ovaries triggers menopause if you have not already gone through it, leading to symptoms like hot flashes, mood changes, and bone density loss. Radiation therapy can cause fatigue, skin irritation in the treated area, diarrhea, and vaginal dryness or narrowing. Chemotherapy side effects often include nausea, hair loss, fatigue, increased risk of infection, and numbness or tingling in the hands and feet. Hormone therapy may cause weight gain, mood swings, or increased risk of blood clots. Your healthcare team will help you manage these side effects and can provide medications or other support to improve your comfort.^[4]

Treatment in Clinical Trials: Exploring New Possibilities

While standard treatments work well for most people with stage I endometrial cancer, researchers are constantly investigating new therapies that might be even more effective or have fewer side effects. Clinical trials are carefully designed studies that test these new approaches before they become widely available. Participating in a clinical trial gives you access to cutting-edge treatments and contributes to scientific knowledge that can help others in the future.

Clinical trials are divided into phases based on what they aim to discover. Phase I trials test a new drug or treatment in a small group of people to evaluate its safety, determine the right dosage, and identify side effects. These studies are the first step in understanding whether a new therapy is safe enough to use in humans. Phase II trials involve more participants and focus on whether the treatment actually works—for example, whether it shrinks tumors or slows cancer growth. These studies also continue to monitor safety. Phase III trials compare the new treatment to the current standard of care in a large group of people. These trials are crucial for determining whether the new therapy is better, equivalent, or less effective than what is already available. If a phase III trial shows positive results, the treatment may be approved for general use.^[14]

One area of research involves immunotherapy, which harnesses the body’s own immune system to fight cancer. Some immunotherapy drugs work by blocking proteins that prevent immune cells from attacking cancer. These drugs, called checkpoint inhibitors, have shown promise in certain types of endometrial cancer, particularly those with specific genetic mutations. For example, cancers with mismatch repair deficiency (also known as microsatellite instability-high or MSI-H) may respond well to immunotherapy. Researchers are studying these drugs in clinical trials to see if they can improve outcomes for people with stage I disease who have high-risk features.^[14]

Another promising area is targeted therapy, which uses drugs designed to attack specific molecules or pathways that cancer cells rely on to grow and survive. For endometrial cancer, scientists are investigating drugs that target pathways like PI3K/AKT/mTOR, which are often overactive in cancer cells. Other targeted therapies focus on blocking the effects of hormones or growth factors that fuel cancer growth. Some of these drugs are being tested alone, while others are combined with chemotherapy or immunotherapy to see if the combination is more effective.^[14]

Clinical trials are being conducted around the world, including in the United States, Canada, Europe, and other regions. Eligibility for a trial depends on many factors, including the stage and grade of your cancer, your previous treatments, your overall health, and the specific requirements of the study. Your doctor can help you search for trials that might be a good fit and explain the potential benefits and risks. Many cancer centers have dedicated staff who assist patients in finding and enrolling in clinical trials.

Most common treatment methods

• Surgery
  • Total hysterectomy to remove the uterus and cervix
  • Bilateral salpingo-oophorectomy to remove both fallopian tubes and ovaries
  • Sentinel lymph node biopsy to check if cancer has spread to nearby lymph nodes
  • Minimally invasive techniques such as laparoscopy or robotic-assisted surgery for faster recovery
• Radiation therapy
  • Brachytherapy (internal radiation) delivered inside the vagina to target remaining cancer cells
  • External beam radiation therapy directed at the pelvis from outside the body
  • Used as adjuvant therapy after surgery for intermediate or high-risk cases
  • Can be used as primary treatment for people who cannot have surgery
• Chemotherapy
  • Carboplatin and paclitaxel combination is the most common regimen
  • Given intravenously in cycles with rest periods in between
  • Used for high-risk stage I disease or aggressive cancer types like carcinosarcoma
  • May be combined with radiation therapy for better outcomes in some cases
• Hormone therapy
  • Progestin medications (synthetic progesterone) to slow cancer growth
  • Can be given as oral pills or through an intrauterine device (IUD)
  • Considered for low-grade cancers or when surgery is not possible
  • May be used for fertility preservation in young patients, with close monitoring