Recurrence, metastasis rates in extraskeletal myxoid chondrosarcoma remain high

A recent study on patients with extraskeletal myxoid chondrosarcoma (EMC) reports a high rate of recurrence, high propensity for metastasis, and high rate of progression of metastatic disease on systemic therapy.

These findings support those from published literature on EMC, according to the researchers, who identified all patients with EMC seen at the University of Michigan Sarcoma Center, US, between 1998 and 2021. They also carried out a chart review to assess demographics, tumour characteristics, treatments, and outcomes.

Forty-four patients with EMC (median age at diagnosis 57 years, 80 percent male) had been identified, with a median follow-up of 49.7 months. Of these, 34 (77 percent) had locoregional disease at diagnosis, and 26 (59 percent) developed a metastatic disease.

Recurrence after locoregional curative-intent surgery happened in 15 patients, of whom 11 (73 percent) had metastatic disease. Overall survival rates at 5 years were 79 percent, 86 percent, and 58 percent for all patients, for those with locoregional disease, and for those with metastatic disease, respectively.

In patients with locoregional disease, 5-year disease-free survival was 43 percent, while the metastasis-free survival after surgery was 53 percent. In addition, 1-year progression-free survival for metastatic disease from the start of first-line systemic therapy was 43 percent.

Only older age showed a statistically significant association with improved prognosis. However, perioperative radiotherapy, lower histologic grade, and negative margins demonstrated directional associations with outcomes.

“EMC is an ultrarare soft tissue sarcoma, and a limited number of studies are published regarding its clinical course and efficacy of treatment,” the investigators said.