The role of adjuvant (post-operative) chemotherapy remains controversial. However, subsets of patients with specific histological subtypes and prognostic variables are likely to benefit from chemotherapy.
The chemotherapy used in ARST0332:
- Pre-operative ifosfamide and doxorubicin (ID) used.
- One of the most active and commonly used combinations to treat non-RMS.
- Radiographic response rate to this chemotherapy was 35-40%.
- Synovial sarcomas much more likely to have a good pathologic response ( >/= 90% necrosis) than other histologies.
- Outcomes remained poor for patients with large, high-grade tumors and unresectable or metastatic disease.
The next COG study ARST1321 for intermediate and high-risk non-RMS adds a multitargeted tyrosine kinase inhibitor (TKI) to standard chemotherapy (ifosfamide and doxorubicin) called Pazopanib. This will be used to target multiple signaling pathways that may be disrupted in many non-RMS. Single agent Pazopanib has shown antitumor activity in patients with leiomyosarcoma, synovial sarcoma, chondrosarcoma and other sarcomas.
The recent development of new molecular treatment approaches to specific tumor targets may make it possible to identify specific agents tailored to each histotype.
A meta-analysis of updated data from adult soft tissue sarcoma patients from all available randomized trials concluded that recurrence-free survival was better with adjuvant doxorubicin based chemotherapy for patients with high-grade tumors larger than 5 cm.
The largest prospective pediatric trial failed to demonstrate any benefit with adjuvant vincristine, dactinomycin, cyclophosphamide, and doxorubicin.
In the results of a pooled data analysis from United States and European groups, most patients received initial chemotherapy: major responses were recorded in 41% and minor in 16% of cases.
References:
Role of Chemotherapy in pediatric nonrhabdomyosarcoma soft-tissue sarcomas. Expert Rev Anticancer Ther. 2008 Jun;8(6):929-38. doi: 10.1586/14737140.8.6.929.Ferrari A.
