OBJECTIVE: To establish outcome and optimal timing of local control for patients with nonmetastatic Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) of the chest wall. METHODS: Patients < or =30 years of age with ES/PNET of the chest wall were entered in 2 consecutive protocols. Therapy included multiagent chemotherapy; local control was achieved by resection, radiotherapy, or both. We compared completeness of resection and disease-free survival in patients undergoing initial surgical resection versus those treated with neoadjuvant chemotherapy followed by resection, radiotherapy, or both. Patients with a positive surgical margin received radiotherapy. RESULTS: Ninety-eight (11.3%) of 869 patients had primary tumors of the chest wall. Median follow-up was 3.47 years and 5-year event-free survival was 56% for the chest wall lesions. Ten of 20 (50%) initial resections resulted in negative margins compared with 41 of 53 (77%) negative margins with delayed resections after chemotherapy (P = 0.043). Event-free survival did not differ by timing of surgery (P = 0.69) or type of local control (P = 0.17). Initial chemotherapy decreased the percentage of patients needing radiation therapy. Seventeen of 24 patients (70.8%) with initial surgery received radiotherapy compared with 34 of 71 patients (47.9%) who started with chemotherapy (P = 0.061). If a delayed operation was performed, excluding those patients who received only radiotherapy for local control, only 25 of 62 patients needed radiotherapy (40.3%; P = 0.016). CONCLUSION: The likelihood of complete tumor resection with a negative microscopic margin and consequent avoidance of external beam radiation and its potential complications is increased with neoadjuvant chemotherapy and delayed resection of chest wall ES/PNET.