From the Guidelines
Alveolar soft part sarcoma (ASPS) of the thigh should be treated with wide surgical resection with clear margins as the cornerstone of therapy, followed by consideration of targeted therapies like anti-angiogenic TKI, atezolizumab, or combination of TKI/checkpoint inhibitor for metastatic disease, as recommended by the most recent guidelines 1.
Treatment Overview
The treatment of ASPS involves a multidisciplinary approach, including surgery, radiation therapy, and medical oncology.
- Surgical resection with clear margins is the primary treatment for localized disease.
- Radiation therapy may be considered to reduce local recurrence risk.
- Chemotherapy has limited effectiveness against ASPS, but may be considered for advanced disease.
Targeted Therapies
For metastatic ASPS, targeted therapies have shown promise, including:
- Anti-angiogenic TKI, such as pazopanib or sunitinib, which have shown better response rates due to the tumor's highly vascular nature 1.
- Atezolizumab, a PD-L1 inhibitor, which has been approved by the FDA for the treatment of ASPS 1.
- Combination of TKI/checkpoint inhibitor, which may offer improved outcomes for patients with metastatic disease 1.
Follow-up and Monitoring
Regular follow-up with imaging is essential, as ASPS can metastasize to lungs, brain, and bones even years after initial treatment.
- Patients should be monitored with MRI of the primary site and chest imaging every 3-6 months for the first 2-3 years, then annually thereafter.
- The unique genetic translocation t(X;17) that creates an ASPSCR1-TFE3 fusion protein in ASPS explains its resistance to conventional chemotherapy, highlighting the importance of targeted therapies in treatment 1.
From the Research
Alveolar Sarcoma of the Thigh
- Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor that usually affects young patients, with the thigh being a common location of primary tumor 2.
- The clinical presentation of ASPS can be misleading, with some cases being initially diagnosed as benign soft tissue tumors or hemangiomas, leading to delayed treatment 2.
- The treatment principle for alveolar soft tissue sarcoma is massive resection, and when the surgical margin is questionable, radiation treatment can be added for prevention of local recurrence 2.
Treatment and Outcome
- Complete surgical resection remains the standard management strategy for ASPS, with radiotherapy being used for patients with micro- or macroscopical incomplete residue or questionable surgical margins 3.
- Chemotherapy is controversial, but some target drugs and immune checkpoint inhibitors have shown antitumor activity 3.
- The use of tyrosine kinase inhibitors and immune checkpoint inhibitors has emerged as a new treatment strategy for ASPS, providing antitumor activity and potentially improving patient outcomes 4, 5.
Metastasis and Recurrence
- ASPS has a high potential for metastasis, with the lung, bone, and brain being common metastatic sites 6, 5.
- Even after 5 years of general treatment, outpatient department follow-up is needed to monitor for local recurrence and metastases 2.
- Combination therapy, including multiple target agents and/or immune checkpoint inhibitors, may prolong survival time in patients with recurrence, distant metastasis, or refractory ASPS 3.