The radiographic follow-up of patients with Ewing sarcoma: a demonstration of a general method

An analysis of the patterns of detectable tumor recurrence using the concepts of hazard rate, predictive value, and cumulative probability was undertaken to assess the appearance of metastases in Ewing sarcoma. This study comprises 107 patients who were seen between 1964 and 1977. The distribution of the sites of metastases indicates that repeated examinations of both lungs and bones are necessary for the effective surveillance of both truncal and extremity primary lesions. The hazard rates for metastases suggest that these serial examinations should be concentrated early in the follow-up period for truncal primaries and more uniformly distributed for extremity primaries. The method used is general and is applicable to any disease for which the surveillance for recurrence or a complication is of major concern. The results of the analysis may be used in the selection and scheduling of follow-up examinations for patients with Ewing sarcoma, and in advising the patient of the prognosis for continued remission.