Uterine sarcomas are uncommon and most general gynaecologists would never get enough cases to become an expert in this entity. They are aggressive tumours arising from the endometrium or myometrium of the uterus.
- Uterine sarcomas are uncommon but aggressive tumours.
- Surgery is the cornerstone of all treatment. Uterine sarcomas do not respond well to any type of adjuvant treatment.
- A reliable differential diagnosis between benign fibroids and uterine sarcomas is infeasible.
- Morcellation of uterine fibroids needs to be avoided under all circumstances so that an incidental finding of a sarcoma does not compromise the patientʼs prognosis.
- Gynaecological surgeons need to be familiar with various surgical techniques to maintain the intactness of specimens upon their extraction from the pelvis.
Unintended mismanagement of these tumours by gynaecological surgeons can have a catastrophic effect on the patientʼs chance of survival.
This article will outline the perils of uterine sarcoma management and offer solutions to safe management.
Uterine sarcomas account for approximately 5% of malignancies arising in the uterus and are typically more aggressive than typical endometrioid endometrial cancers. Classification of uterine sarcomas follows the tissue type of origin and can arise from smooth muscle (leiomyosarcomas), endometrium (endometrial stromal sarcomas) or non-specific connective tissue. The malignant mesenchymal component may be mixed with a benign epithelial component (adenosarcomas). Heterologous sarcomas contain tissue with non-native differentiation (cartilage, bone).
Carcinosarcomas have been classified as sarcomas previously but are now classified as epithelial malignancies.
Risk factors and presentation
Increasing age, long-term use of tamoxifen (e.g. for breast cancer), previous pelvic radiation treatment (e.g. for rectal cancer) and genetic mutations (hereditary kidney cancer) are risk factors.
At the Queensland Centre for Gynaecological Cancer (serving a population of 4.5 million) we see approximately 30 patients with uterine sarcomas every year with the incidence increasing. In our series, patients with uterine sarcomas are slightly younger (56 years) than patients with epithelial uterine malignancies.
Clinical presentation is unspecific. However, the majority of patients present with abnormal uterine bleeding, pain and abdominal distension, which are symptoms shared with common and benign gynaecological conditions, including fibroids. The traditional textbook teaching suggests that a rapidly growing mass arising from the uterus is considered suspicious for sarcoma.
The diagnosis of a uterine sarcoma is based on histology. Unfortunately, a significant percentage of uterine sarcomas are diagnosed incidentally following a hysterectomy or a myomectomy.
Imaging – the accuracy of medical imaging (CT, MRI, US) is low and a differential diagnosis is unreliable.
Blood tests – blood tumour markers (e.g. CA125, HE4) do not contribute to the diagnosis.
Pelvic vaginal/rectal examination – sometimes the uterus is enlarged but it may also be normally sized and mobile.
Pap – cervical cancer screening may inadvertently demonstrate atypical cells that require further investigations.
Hysteroscopy, D&C or endometrial sampling – obtaining endometrial tissue will reveal the diagnosis in between 40% and 60% of patients diagnosed with uterine sarcoma.
In the clinical assessment, practitioners should be alert to the possibility of malignancy, if there is:
- Rapidly expanding mass
- Abnormal uterine bleeding, including postmenopausal bleeding
- Evidence of secondary spread
In summary, and even applying the greatest care, only some uterine sarcomas can be reliable diagnosed prior to hysterectomy.
Treatment of patients with uterine sarcomas
Medical imaging: A high percentage of patients present with distant metastatic disease at the time of diagnosis. We recommend a CT scan of the pelvis, abdomen and chest for all patients diagnosed with uterine sarcomas. It is likely that the general use of PET/CT scan will improve the detection rate of distant involvement.
I. Preoperative diagnosis
a. Disease confined to uterus
We recommend a total laparoscopic hysterectomy, BSO and surgical exploration (including biopsies where appropriate) to determine the extent of the disease.
As there is no reliable method to differentiate benign fibroids from uterine sarcoma we strongly recommend abstaining from any morcellation or any other procedures that could aid the spillage of tumour (cork screws). If a tumour is larger than expected the options are 1) morcellation within a containment system vaginally or abdominally; or 2) a small laparotomy to remove the specimen (the procedure can be converted to a laparoscopy again).
Surgical staging: There is no evidence that a full lymph node dissection improves health outcomes. In patients with disease apparently confined to the uterus the incidence of positive lymph nodes is low across all subtypes of uterine sarcomas. The accuracy of sentinel node dissection in uterine sarcomas is still unknown.
b. Extrauterine disease
If cytoreduction is achievable, it is recommended. If cytoreduction is not feasible, we evaluate how feasible a hysterectomy is for palliation (bleeding).
II. Postoperative diagnosis
- All patients have a CT scan of the pelvis, abdomen and chest.
- Women who had a total hysterectomy, BSO and disease limited to the uterus may not need anything further.
- Women who had a hysterectomy without BSO or women who had a subtotal hysterectomy are advised to have their adnexae and the cervical stump removed.
- Patients who had assumed spillage of tumour should have a laparoscopic exploration to check for extrauterine disease.
The FIGO staging system for carcinosarcoma vs. leiomyosarcoma vs. adenosarcoma vs. endometrial adenocarcinoma is different.
Adjuvant treatment: Whether any form of chemotherapy or radiation treatment following surgery is effective remains unknown. In general, chemotherapy has modest effect on survival outcomes. Radiation treatment is ineffective. Whether the combination of radiation treatment plus chemotherapy improves survival outcomes is under investigation.
Low-quality evidence is available to support the use of progestins, GnRh analogues and aromatase inhibitors in patients with recurrence who did not have treatment before.
Follow-up: Data to support ongoing follow-up or to demonstrate a survival benefit through regular follow-up are not available. Despite the lack of evidence, traditional guidelines suggest patients are seen regularly and have a pelvic vaginal examination with medical imaging.
Prognosis: Patients with stage 1 disease (80%) have better 5-year survival rates compared to patients with stage 4 disease or undifferentiated sarcomas (20%).
An unacceptably high number of patients will be diagnosed postoperatively incidentally.
Uterine sarcomas are aggressive tumours responding poorly to chemotherapy.
Spillage of tumour through unguarded morcellation of tumour will decrease the survival chances significantly.
Therefore, free morcellation of uterine tissue must be avoided under all circumstances.
Contained morcellation (using a containment device) is a superior alternative.