Long-Term Response after 94 Cycles of Trabectedin in a Patient with Metastatic Leiomyosarcoma of the Lower Extremity.

Leiomyosarcomas of the lower extremity are extremely rare disorders and account for 10-15% of limb soft tissue sarcomas. These tumours have poor prognosis and even in early stages, patients persist at high risk for local and distant relapse; consequently, the treatment of advanced leiomyosarcoma of the lower extremity embodies a substantial defy. We present the case of a 73-year-old man diagnosed with metastatic lower extremity leiomyosarcoma of the hallux soft tissue, and with bone, lung and lymph node metastasis. After core needle biopsy confirmation of high-grade fusocellular sarcoma, the patient underwent surgery of the primary tumour and received anthracycline-based chemotherapy. However, after a 7-month progression-free survival period, a CT revealed lung disease progression. Sequentially, the patient was treated with trabectedin (Yondelis®) at a dose of 1.5 mg/m² resulting in complete remission of the lung metastasis and stable disease of the remaining lesions after 26 months of treatment. Afterwards, the patient started on maintenance therapy with trabectedin, resulting in long-lasting stable disease, as he was able to receive 94 cycles with very acceptable quality of life. Finally, in March 2019, the patient died of community-acquired pneumonia without objective progression disease. This clinical case reports the first patient ever treated with 94 cycles of trabectedin. Our results additionally confirm that trabectedin wields relevant oncostatic benefits with a manageable safety profile and without cumulative toxicities. Trabectedin properties enable a maintenance long-term therapy (until disease progression or unbearable toxicity), with a high impact on survival and with a preserved quality of life.