Sarcoma

Incidence

Uterine sarcomas comprise approximately 3% of uterine cancers.

Risk Factors

The only proposed predisposing factor for uterine sarcomas is prior history of pelvic radiation.

Pathology

Uterine sarcomas arise from mesodermal derivatives which include uterine smooth muscle, endometrial stroma, and blood and lymphatic vessel walls. In general, the number of mitoses per10 hpf is the most reliable predictor of biologic behavior.

Classification

Type
Homologous
Heterologous

Pure
Leiomyosarcoma

Stromal Sarcoma
Rhabdomyosarcoma

Chondrosarcoma

Osteosarcoma

Liposarcoma

Mixed
Malignant Mixed Mesodermal Tumors with Homologous Components
Malignant Mixed Mesodermal Tumors with Heterologous Components

Pure- Only contain malignant mesodermal elements.
Mixed- Malignant mesodermal and malignant epithelial elements are present.
Homologous and heterologous refer to whether the malignant mesodermal elements are normally present in the uterus (i.e., homologous- smooth muscle and stroma; heterologous-striated muscle and cartilage)

From a practical clinical standpoint uterine sarcomas can be divided into four major groups:
1. Endometrial Stromal Sarcomas (8%)
2. Leiomyosarcomas (40%)
3. Malignant Mixed Mesodermal Tumors(50%)
4. Adenosarcomas and pure heterologous sarcomas and other variants comprise the remaining 1-2%.

Routes of Spread

In general the sarcomas have a propensity for early hematogenous spread and lymphatic dissemination occurs in 1/3 of patients with disease clinically confined to the uterus.

Clinical Features

1. Endometrial Stromal Sarcoma- Patients on the average range in age from 42-53 years, but young women or girls maybe affected. The primary complaint is abnormal vaginal bleeding, uterine enlargement and low abdominal pain. Diagnosis is easily made by EMB or D&C secondary to tumor primarily involving the endometrium.

2. Leiomyosarcoma- Patients range in age from45-55 on average. These tumors primarily arise de-novo from uterine smooth muscle and only rarely arise from an existing leiomyoma. Common signs and symptoms include low abdominal pressure or pain, palpation of a mass, or abnormal vaginal bleeding. Diagnosis is difficult preoperatively with only approximately 15% diagnosed on EMB or D&C.

3. Malignant Mixed Mesodermal Tumors- These tumors occur in older patients with the great majority diagnosed between65-75 years of age. These women have several factors in common with those patients with endometrial adenocarcinoma: nulliparity, obesity, and diabetes. The most common presenting complaints are vaginal bleeding, low abdominal pain, vaginal discharge, and a palpable abdominal mass. In up to 50% of cases tumor can be seen protruding through the cervical os.

4. Adenosarcoma- These tumors can occur at any age but are most common in the fifth decade of life. The most common presenting complaint is abnormal uterine bleeding and in 50% of cases tissue can be seen protruding from the cervical os. Uterine enlargement on physical exam is also not uncommon.

Pretreatment Work-Up

1. EMB and/or D&C
2. Serum CA-125
3. Chest X-ray
4. Routine lab work and pre-op evaluation

Staging

No official staging system for sarcomas, therefore the FIGO staging system for endometrial carcinoma is used.

Treatment

The only treatment of curative value is surgical excision. Pelvic radiotherapy has a role in local control of tumor, but because of their propensity for early hematogenous spread pelvic radiotherapy does not effect outcome. An exception to the option of radiotherapy is leiomyosarcomas which are generally not responsive to radiotherapy. Chemotherapy drugs which have shown some activity against uterine sarcomas include Cisplatin, Adriamycin. and Ifosfamide. Leiomyosarcomas are more sensitive to Adriamycin. In certain cases where the sarcomas contain hormone receptors there maybe some benefit to hormonal therapy with megace or tamoxifen.

Survival

The survival for endometrial stromal sarcomas, leiomyosarcomas and and MMT are essentially the same.

Stage I- 50%
Stages II-IV- 15% or less.