Multifocal relapse after concurrent chemotherapy and radiotherapy of small cell lung cancer

Twenty-one patients with small cell lung cancer (SCLC) were treated with cyclophosphamide (1250 mg/m2), Adriamycin (40 mg/m2), vincristine (2 mg) every three weeks. Thoracic radiotherapy (3000 rad: 10 or 15 fractions) began four weeks after starting chemotherapy. Patients with brain metastases received cranial irradiation. Thirteen of 19 evaluable patients responded to therapy (four complete responses). Sixteen of 19 had significant intrathoracic response (eight complete). Of the three patients without an intrathoracic tumor response, two had simultaneous progression in systemic locations and only one had intrathoracic progression preceding systemic progression. Intrathoracic relapse preceded systemic relapse in two patients, was simultaneous with it in six and followed systemic relapse in four others. Therefore only three patients had intrathoracic tumor progression or relapse preceding systemic progression or recurrence. The more intensive course of radiotherapy was significantly better in preventing intrathoracic tumor progression. Although intrathoracic tumor control is important, primary failure of therapy or relapse appears to be multifocal. Future attention must be directed toward control of multiple potential sites of relapse.