New tool can aid treatment decisions in Ewing sarcoma

NEW YORK (Reuters Health) - A new risk factor score can help guide treatment decisions for patients with primary disseminated multifocal Ewing sarcoma (PDMES), say the researchers who developed it.

Survival rates with this disease can be dismal. The new tool lets doctors "identify very high-risk patients with PDMES for experimental treatments early," said lead author Dr. Ruth Ladenstein from St. Anna Children's Hospital, Children's Cancer Research Institute, Vienna, Austria, and colleagues.

Patients get 1 point each for age older than 14 years, bone marrow metastasis, one bone lesion, and additional presence of lung metastases and 1.5 points each for primary tumor volume of at least 200 mL and more than one bone lesion.

As reported online June 14th in the Journal of the Clinical Oncology, the researchers allocated patients into 3 groups based on their risk score at diagnosis, with significantly different outcomes in terms of event-free survival (i.e., freedom from disease progression, new metastases, second malignancies, or death from any cause) at approximately 4 years. Group 1, with a score of 3 or less (82 patients) had an event-free survival of 50%; group 2, with scores between 3 and 5 (102 patients) had an event-free survival of 25%; and group 3, with scores of 5 and higher (70 patients) had an event-free survival of 10%.

Dr. Ladenstein's team then validated the risk score by applying it to 44 patients with PDMES from a previously published French study. In this cohort, event-free survival rates were 50% in group 1, 20% in group 2, and 9% in group 3.

The authors developed their scoring system using data on patients enrolled in a trial of high-dose therapy with busulfan-melphalan followed by autologous stem-cell transplantation after induction therapy (median age, 16 years).

The 3-year event-free survival rate was 27%, and the overall survival rate was 34%, with a median follow-up of 3.8 years after diagnosis and 84% of survivors followed for more than 2 years.

The median survival was 1.6 years for all patients, but less than a month for the 44 patients with early disease progression before high-dose chemotherapy.

On Cox regression analysis, the hazard ratios for disease events were 1.6 for age greater than 14, 1.8 for primary tumor volume greater than 200 mL, 2.0 for more than one bone metastatic site, 1.6 for bone marrow metastases, and 1.5 for additional lung metastases.

When Ewing sarcoma metastases are present at diagnosis, which occurs in as many as one-third of patients, reported survival rates range from 9% to 41%, the investigators say.

"Further improvements of treatment strategies in this highest risk group of patients with PDMES are urgently needed," they add. "This may include targeted therapies, which are currently being explored in early clinical trials, as well as refinement of high-dose therapy concepts allowing for a better local control rate."

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