Uterine Carcinosarcoma (Malignant Mixed Müllerian Tumor), from the CureRays guide library.

Uterine carcinosarcoma is an aggressive cancer of the uterus that contains two different cancer types blended together; treatment combines surgery, chemotherapy with carboplatin and paclitaxel, and often pelvic radiation.

What it is.

Uterine carcinosarcoma, also called malignant mixed Müllerian tumor (MMMT), is an uncommon but aggressive cancer of the lining of the uterus. What makes it unusual is that under the microscope it contains two intermingled cancer components — a carcinoma part (gland-like cells) and a sarcoma part (connective-tissue-like cells) — both arising from the same abnormal cell. It is now understood to be a high-grade form of endometrial (uterine lining) cancer that behaves more aggressively than typical endometrial cancer, often affecting women after menopause. The most common warning sign is abnormal vaginal bleeding. Because it spreads readily, treatment is multimodal: surgery to remove the uterus, ovaries, and tissues for staging; chemotherapy with carboplatin and paclitaxel, now established as the preferred regimen; and pelvic radiation in many cases, especially for disease that has reached beyond the uterus. Even when caught early it deserves aggressive, coordinated treatment.

How radiation treats it.

Radiation damages the DNA inside cancer cells so they can no longer divide. In uterine carcinosarcoma, radiation is used after surgery to lower the chance the cancer returns in the pelvis or at the top of the vagina, where recurrences commonly appear. External-beam radiation, shaped precisely with modern IMRT, treats the broader pelvis, while vaginal brachytherapy places a source right where it's needed for a concentrated dose with minimal exposure to the bladder and bowel. Studies show the benefit is greatest when radiation is combined with chemotherapy, particularly in stage III disease. Treatment is painless, given in short sessions, and leaves no radioactivity in your body.

The ways we can treat it.

Pelvic external-beam radiation (IMRT). Intensity-modulated radiation shapes the dose to the pelvis to treat areas where the cancer is most likely to return, while sparing the bladder and bowel as much as possible.

Vaginal brachytherapy. A radiation source is placed inside the vagina for a short time to deliver a concentrated dose to the top of the vagina, a common site of recurrence, with little exposure to surrounding organs.

Combined chemoradiation. Pairing radiation with chemotherapy attacks both local disease in the pelvis and microscopic cells elsewhere, an approach associated with improved outcomes in advanced-stage disease.

Questions we hear often.

Why does my cancer have two different parts? Uterine carcinosarcoma contains both a carcinoma (gland-like) and a sarcoma (connective-tissue-like) component, both arising from one abnormal cell. It's now considered a high-grade type of uterine (endometrial) cancer, and it tends to behave more aggressively than ordinary endometrial cancer.

What treatments will I likely need? Most women have surgery to remove the uterus, ovaries, and tissues for staging, followed by chemotherapy with carboplatin and paclitaxel. Pelvic radiation is often added — especially for more advanced disease — to reduce the chance of the cancer returning.

Will I need both chemotherapy and radiation? Often, yes. Studies show that combining chemotherapy with radiation improves outcomes compared with either alone, with the biggest benefit in stage III disease. Your gynecologic-oncology team will tailor the combination to your stage and individual situation.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.