Uterine sarcoma is a term that is used to describe different types of cancer that develop within the uterus.  

Uterine sarcoma is a rare cancer, affecting only about 5,000 people in the United States each year. Uterine sarcoma is commonly diagnosed in women who are in their 40s through their 60s, although it is possible for it to occur in younger women. Although any woman may develop uterine sarcoma, the most common type, leiomyosarcoma, is twice as common in Black women than in white women.  

How well a woman responds to treatment may depend on how advanced her uterine sarcoma is at the time of diagnosis. This form of cancer tends to grow and spread quickly. When it is caught early, treatment is more likely to be effective; about two out of three women who are diagnosed early with uterine sarcoma remain cancer-free after five years.  

“Surgery remains the most effective treatment for the care of patients diagnosed with uterine sarcoma,” says Alessandro Santin, MD, co-chief of the Section of Gynecologic Oncology and disease aligned research team leader for the Gynecologic Oncology Program at Smilow Cancer Hospital.

Uterine sarcoma refers to different cancers that occur in the muscle or connective tissue of the uterus. It is different than cancer of the uterine lining, or endometrium, which is called endometrial carcinoma.  

There are three different types of uterine sarcoma:  

• Leiomyosarcoma, the most common type of uterine sarcoma, develops within the muscle walls of the uterus.
• Endometrial stromal sarcoma, a less common type of uterine sarcoma, forms in the tissue that connects the uterine lining to the walls of the uterus.
• Undifferentiated sarcomas of the uterus is the rarest of all three. This form of uterine sarcoma may begin in the uterine muscle or the uterine lining and tends to grow and spread quickly.

When women have uterine sarcoma, they may experience:

• Abnormal vaginal bleeding between menstrual periods
• Vaginal bleeding after menopause
• Pelvic pain
• Abdominal pain
• Bloating
• A feeling of abdominal fullness
• A palpable mass in the pelvis or vagina
• Frequent urination
• Vaginal discharge that doesn’t improve with medication
• Constipation

The following factors may raise a woman’s risk of this cancer:

• Having had radiation therapy to treat a previous cancer in the pelvic region
• Taking the drug tamoxifen (to prevent or treat breast cancer) for five years or longer
• Having a family history of hereditary leiomyomatosis and renal cell carcinoma syndrome, a rare inherited disorder
• Being a survivor of retinoblastoma, a rare eye cancer that occurs in childhood

When doctors suspect uterine sarcoma, they perform a physical exam, ask patients about personal and family medical history, and order certain tests that may detect the cancer.  

A doctor will ask the patient about the symptoms that she has experienced, including abnormal vaginal bleeding, discomfort or pain in pelvis or abdomen, and changes in bathroom habits. The doctor will also find out whether there has been a previous cancer diagnosis, and if so, what type of cancer it was and what treatment they received.  

The doctor will also perform a pelvic exam and, if a palpable mass is felt, further testing may be required. When doctors suspect uterine sarcoma, they will order imaging tests, such as transvaginal ultrasound, CT scan, or MRI. If a mass is seen on the imaging tests, a tissue biopsy will be required to make a diagnosis.  

Sometimes, uterine sarcoma is diagnosed after a woman has had a hysterectomy to treat painful fibroids. Additional surgery may be needed, depending on what was removed during the hysterectomy.  

Some people may worry that fibroids are related to uterine sarcoma, but they are not. Fibroids are benign (noncancerous) masses that form in the muscle walls of the uterus, and are not—or rarely—linked to uterine sarcoma. Even if fibroids are undiagnosed and go untreated, they do not progress to uterine sarcoma.

The standard treatment for uterine sarcoma is hysterectomy, plus surgical removal of neighboring parts of the reproductive tract. A woman with uterine sarcoma will have her uterus removed, along with both of her ovaries and both fallopian tubes.  

Doctors may also remove local lymph nodes, which will be biopsied to determine if the cancer has spread beyond the uterus. They may also rinse the pelvic cavity with a saline solution (salt water) after surgery, which allows them to check for the presence of cancerous cells; this is another way to see if the cancer has spread outside of the uterus.  

After surgery, if doctors believe that the cancer was completely contained within the uterus and did not spread to other tissue, no further treatment may be needed. In other instances, patients may need chemotherapy, with or without radiation therapy, to eradicate any remaining cancer cells that may not have been removed during surgery. Women who have endometrial stromal sarcoma may also require hormone therapy after surgery.

About two thirds (66%) of women who are diagnosed with early-stage leiomyosarcoma survive 5 years or longer. The prognosis worsens if the cancer has spread beyond the uterus, declining to a 5-year survival rate of 13 to 34%. When uterine sarcoma spreads, it often metastasizes to the lungs or the abdomen.

“With the goal to personalize cancer treatment modalities for uterine sarcoma patients, Yale researchers have recently reported the most comprehensive genetic analysis of uterine leiomyosarcoma,” says Dr. Santin. “This study provided the first preclinical evidence that a specific mutation profile identified through genetic sequencing may be predictive of drug response to targeted drugs both in vitro as well as in vivo. Accordingly, patients diagnosed with leiomyosarcoma at Yale may have access to personalized treatment modalities.”