Response to initial therapy factors

Multiple studies have shown that patients with minimal or no residual viable tumor after presurgical chemotherapy have a significantly better EFS than do patients with larger amounts of viable tumor.[21,73-76]; [77][Level of evidence C2] In particular, patients with localized disease who have no viable tumor seen at the time of local-control surgery appear to have markedly favorable outcomes.[21]; [77][Level of evidence C2] Female sex and younger age predict a good histological response to preoperative therapy.[78] For patients who receive preinduction- and postinduction-chemotherapy PET scans, decreased PET uptake after chemotherapy correlated with good histological response and better outcome.[79-81]

Patients with poor response to presurgical chemotherapy have an increased risk of local recurrence.[82]

A retrospective analysis of risk factors for recurrence was performed in patients who received initial chemotherapy and underwent surgical resection of the primary tumor.[83][Level of evidence C1] Among 982 patients with a median follow-up of 7.6 years, the following was reported:

In a retrospective cohort of 148 patients with pulmonary metastatic Ewing sarcoma, 41.2% had radiographic resolution of lung nodules after initial induction chemotherapy.[84] These patients had superior OS compared with patients who had residual nodules at end-induction (71.2% vs. 50.2% at 5 years). Particularly favorable outcomes were seen in the patients who had early clearance of lung nodules and received consolidative whole-lung radiation therapy (5-year OS rate, 85.2%).