Purpose: Bone marrow (BM) status is a critical matter when intensified chemotherapy with bone marrow rescue is proposed to improve the survival of patients with poor prognosis Ewing's sarcoma (ES): metastatic or relapsing disease. A systematic bone marrow investigation was performed in all the patients with newly diagnosed ES or relapsing ES to assess their BM status.
Patients and methods: From January 1985 to February 1989, 59 untreated patients and five patients at the time of relapse had a bone marrow investigation under general anesthesia: two BM biopsies and two BM aspirates until May 1986, then two BM biopsies and 10 BM aspirates. The classical method of smearing each BM aspirate was compared to cytocentrifugation of the pool of BM samples after gradient density separation.
Results: The BM was involved in 13 of 59 untreated patients. BM was the single site of metastatic spread in only one patient but was involved in 52% of the patients with metastatic disease at other sites. This involvement was focal in several patients and frequent discrepancies were noted between the aspirates and biopsies at the various sites explored. The number of positive cases of BM involvement discovered by the two methods is somewhat limited. However preliminary results indicate a superior rate of positive smears with the pool technique which did however fail to detect involvement in some cases.
Conclusions: The present study indicates that 1) BM involvement is a frequent event in metastatic ES (52%); 2) is often multifocal and therefore requires extensive BM investigation; and 3) further investigation of the pool technique to facilitate the BM screening is warranted.