Uterine Sarcoma Treatment (Professional)
General Information About Uterine Sarcoma
Other PDQ summaries containing information related to uterine sarcoma include:
Uterine sarcomas comprise less than 1% of gynecologic malignancies and 2% to 5% of all uterine malignancies. The following tumors arise primarily from three distinct tissues:
The three distinct entities are often grouped under uterine sarcomas; however, each type of tumor is currently being studied in separate clinical trials.
Carcinosarcomas (the preferred designation by the World Health Organization [WHO]) are also referred to as mixed mesodermal sarcomas or mullerian tumors. Controversy exists about the following issues:
The stromal components of the carcinosarcomas are further characterized by whether they contain homologous elements (such as malignant mesenchymal tissue considered possibly native to the uterus) or heterologous elements (such as striated muscle, cartilage, or bone, which are foreign to the uterus). Carcinosarcomas parallel endometrial cancer in its postmenopausal predominance and in other of its epidemiologic features; increasingly, the treatment of carcinosarcomas is becoming similar to combined modality approaches for endometrial adenocarcinomas.
Other rare forms of uterine sarcomas also fall under the WHO classification of mesenchymal and mixed tumors of the uterus. These include mixed endometrial stromal and smooth muscle tumors, adenosarcomas (where the epithelial elements appear benign within a malignant mesenchymal background), embryonal botroydes or rhabdomyosarcomas (found almost exclusively in infants), and the latest addition, PEComa—a perivascular epithelial-cell tumor that may behave in a malignant fashion.[2,3] (Refer to the PDQ summary on Childhood Rhabdomyosarcoma for more information.)
The only documented etiologic factor in 10% to 25% of these malignancies is prior pelvic radiation therapy, which is often administered for benign uterine bleeding that began 5 to 25 years earlier. An increased incidence of uterine sarcoma has been associated with tamoxifen in the treatment of breast cancer. Subsequently, increases have also been noted when tamoxifen was given to prevent breast cancer in women at increased risk—a possible result of the estrogenic effect of tamoxifen on the uterus. Because of this increase, patients on tamoxifen should have follow-up pelvic examinations and should undergo endometrial biopsy if there is any abnormal uterine bleeding.[4,5,6]
The prognosis for women with uterine sarcoma is primarily dependent on the extent of disease at the time of diagnosis. For women with carcinosarcomas, significant predictors of metastatic disease at initial surgery include isthmic or cervical location, lymphatic vascular space invasion, serous and clear cell histology, and grade 2 or 3 carcinoma. These factors, along with adnexal spread, lymph node metastases, tumor size, peritoneal cytologic findings, and depth of myometrial invasion correlate with progression-free interval. The presence or absence of stromal heterologous elements, the types of such elements, the grade of the stromal components, and the mitotic activity of the stromal components bear no relationship to the presence or absence of metastases at surgical exploration. However, in one study, women with a well-differentiated sarcomatous component or carcinosarcomas had significantly longer progression-free intervals than those with moderately to poorly differentiated sarcomas for the homologous and heterologous types. The recurrence rate was 44% for homologous tumors and 63% for heterologous tumors. The type of heterologous sarcoma had no effect on the progression-free interval.
For women with leiomyosarcomas, some investigators consider tumor size to be the most important prognostic factor; women with tumors greater than 5.0 cm in maximum diameter have a poor prognosis. However, in a Gynecologic Oncology Group study, the mitotic index was the only factor significantly related to progression-free interval. Leiomyosarcomas matched for other known prognostic factors may be more aggressive than their carcinosarcoma counterparts. The 5-year survival rate for women with stage I disease, which is confined to the corpus, is approximately 50% versus 0% to 20% for the remaining stages.
Surgery alone can be curative if the malignancy is contained within the uterus. The value of pelvic radiation therapy is not established. Current studies consist primarily of phase II chemotherapy trials for patients with advanced disease. Adjuvant chemotherapy following complete resection for patients with stage I or II disease was not established to be effective in a randomized trial. Yet, other nonrandomized trials have reported improved survival following adjuvant chemotherapy with or without radiation therapy.[11,12,13]
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