Uterine sarcomas: histology and its implications on therapy

Uterine sarcomas are rare cancers, they comprise only 5% of all uterine malignancies. There are about 2,000 cases of uterine sarcoma diagnosed annually in the United States. Uterine sarcomas may be categorized as either favorable-risk, low-grade malignancies with a relatively good prognosis or as poor-risk, high-grade cancers that carry a high risk for tumor recurrence and disease progression. Expert histologic review is critical for appropriate diagnosis and management. Uterine sarcoma histologies considered to carry a more favorable prognosis include low-grade endometrial stromal sarcomas and adenosarcomas. The high-grade sarcomas include high-grade leiomyosarcomas, high-grade undifferentiated endometrial sarcomas, and adenosarcomas with sarcomatous overgrowth. The favorable histology, low-grade uterine sarcomas may be cured with surgical resection of uterus-limited disease. These tumors are often hormone-sensitive, and treatment with hormonal therapies may be efficacious for patients with advanced, unresectable disease. High-grade uterine leiomyosarcomas and undifferentiated endometrial sarcomas carry a high risk for recurrence, even after complete resection of uterus-limited disease. No adjuvant intervention has been shown to improve survival outcomes. Advanced, metastatic disease is generally treated with systemic cytotoxic therapies, which may result in objective response but is not curative. Selected patients with isolated metastatic disease and a long disease-free interval may benefit from metastatectomy.

Trabectedin in advanced uterine leiomyosarcomas: a retrospective case series analysis from two reference centers

BACKGROUND

Treatment options for patients with metastatic uterine leiomyosarcoma are limited. Over the last few years, trabectedin has emerged as an effective agent for patients with advanced soft tissue sarcomas resistant to anthracyclines and ifosfamide. The aim of this retrospective analysis was to look at the efficacy of trabectedin in the subgroup of uterine leiomyosarcoma.

PATIENTS AND METHODS

A retrospective analysis was carried out on patients with uterine leiomyosarcoma treated with trabectedin at two reference sarcoma centers between 2000 and 2010. Radiological response, progression-free and overall survival, as well as serious and unexpected adverse events, were assessed.

RESULTS

Sixty-six patients with metastatic uterine leiomyosarcoma were identified. The median number of previous chemotherapy regimens was 3 (range 1-5). Eleven patients (16%) achieved a partial response and 23 (35%) had a stable disease. The progression-free survival of the entire cohort was 3.3 months (CI 95% 2-5), and the progression-free rate at 3 and 6 months was 53% and 33%, respectively.

CONCLUSIONS

Trabectedin is a therapeutic option in the palliative approach to the metastatic uterine leiomyosarcoma patient.

Treating soft tissue sarcomas with adjuvant chemotherapy

Surgery remains the cornerstone of treatment and the only curative loco-regional approach of localized resectable soft tissue sarcoma (STS) in 2011: the usual first-line treatment is wide margin surgery plus radiotherapy, especially in the case of primary tumors arising in the limbs. An optimal initial R0 resection is one of the most reproducible and reliable prognostic factors for survival in resectable STS. Nevertheless, despite improved local control rates, more than half of the patients still develop and die from unresectable, locally advanced, and/or metastatic disease. Unfortunately, very few cytotoxic drugs have shown activity in this clinical setting with the exception of doxorubicin, ifosfamide, and to a lesser extent, dacarbazine. A conventional-dose, single-agent chemotherapy is still considered to be the standard treatment for metastatic disease. The impact of adjuvant chemotherapy after resection of a high-grade STS remains controversial due to the lack of reproducible impact on survival. Because STS is a rare disease, most trials have involved a relatively small number of patients, with heterogeneous groups of histological/molecular subtypes of sarcomas, initial sites of the disease, and patient's characteristics. In a few trials, a lower risk for local recurrence was observed among patients receiving adjuvant chemotherapy but without any significant gain in overall survival. A meta-analysis based on individual data of these randomized studies has confirmed a significant impact of adjuvant chemotherapy on relapse, either local or metastatic, but without any significant benefit on survival. It should be of importance to include the last recent large trials in a new meta-analysis of source data in order to more carefully analyze a possible benefit of systemic adjuvant chemotherapy in localized sarcoma. Until this study is performed, it is an obvious conclusion that adjuvant chemotherapy has not reproducibly demonstrated its capacity to improve overall survival and relapse-free survival in an unselected population of patients. In 2011, there is therefore an urgent need to determine whether or not there are small subpopulations of patients truly benefiting from adjuvant chemotherapy (with conventional agents), and to identify prospectively these populations. With the exception of male, older than 40 years, with a non-optimal resection of their primary (R1 resection) or in the subgroup of grade 3 STS, no other relevant clinical prognostic/predictive factors have been highlighted. The take home messages in 2011 could be as follows: (1) adjuvant chemotherapy is not recommended routinely in high-grade STS; (2) adjuvant chemotherapy is recommended in patients underwent a R1 resection and with a grade 3 STS; (3) adjuvant chemotherapy cannot rescue an inadequate initial surgery; (4) if selected, chemotherapy has to be contain anthracycline and fractionated adequate dose of ifosfamide (around 9 g/m(2) per cycle); (5) the era of adjuvant chemotherapy trials with the same chemotherapy regimen in all histological subtype of sarcoma is ended; and (6) prognosis of patients with a localized STS starts at diagnosis. The dramatic activity of imatinib in GIST, the heterogeneous outcome of each histological subtype of sarcomas akin to being different diseases, and the high sensitivity of some histological subtypes of sarcoma to specific agents clearly open a new era in the management and the evaluation of new agents in the field of STS. The design of the future adjuvant trials has to incorporate these new findings and new prognostic/predictive biomarkers in order to improve the as yet dismal prognosis of patients developing high-grade localized STS.