Uterine sarcoma is a rare disease. Uterine sarcomas include uterine cancer sarcoma, uterine leiomyosarcoma, and endometrial stromal sarcoma. Endometrial stromal sarcoma is further divided into low-grade and high-grade endometrial stromal sarcomas. Each of them differs in their pathophysiology and clinical course.
There is no specific symptom to suspect uterine sarcoma. In many cases, it is noticed by symptoms indistinguishable from those of uterine myoma and uterine cancer, such as abdominal distention and abnormal bleeding. Characteristic clinical courses needing caution include rapidly enlarged mass after menopause which was diagnosed as uterine myoma.
Uterine leiomyosarcoma is common in women aged 50-55, low-grade endometrial stromal sarcoma in the 40s before menopause, high-grade endometrial stromal sarcoma after menopause, and uterine cancer sarcoma after 60 years occurring in relatively aged women.
Uterine cancer sarcoma often forms a protruded lesion toward the uterine cavity, causing genital bleeding from a relatively early stages, and is often diagnosed as malignant by endometrial examination. In comparison, uterine leiomyosarcoma and endometrial stromal sarcoma occur in the body and muscles of the uterus, which often makes it unable to remove lesions during routine endometrial examination. Imaging tests such as echo and MRI sometimes indicate suspected sarcoma, whereas it is not uncommon that pathological examination reveals sarcoma after the surgery for uterine myoma.
In some cases, determination between benign and malignant tumors is difficult even in pathological diagnosis, which is a characteristic feature of uterus sarcoma that complicates the diagnosis in daily practice.
Surgical removal is the most effective treatment for uterine sarcoma. For advanced cases, multimodal treatment is given by combining several treatments such as chemotherapy using anticancer drugs and radiation therapy. Simple total hysterectomy + bilateral salpingectomy are basically used in surgery while lymph node removal is also considered. For uterine leiomyosarcoma, chopping the tumor at the time of removal is not recommended as it induces recurrence. If only the sarcoma portion is removed, we consider complete removal by reoperation considering possible presence of residual tumors. Low-grade endometrial stromal sarcoma also develops in younger generation before menopause. Because hormone therapy can be effective, function-preserving surgery is often considered.
Chemotherapy for uterine sarcoma includes the use of doxorubicin, ifosfamide, platinum-containing drug, and taxane-containing drug. Pazopanib, trabectedin, eribulin, and other drugs may also be used in advanced or recurrent cases. At present, the effects of these anticancer drug treatments are limited.
For low-grade endometrial stromal sarcoma, medroxyprogesterone acetate and gonadotropin-releasing hormone agonists are used as the first-line drug therapy. However, hormone therapy is rarely effective for high-grade endometrial stromal sarcoma. With the exception of low-grade endometrial stromal sarcoma, uterine sarcoma, even that of early stage, has a very poor prognosis. Development of new drugs and treatments is strongly desired.