Primary Tumor Recurrence after Chemoradiotherapy in Limited Stage Small Cell Lung Cancer

Abstract

<h3>Purpose/Objective(s)</h3> Accounting for 13-15% of lung cancer, small cell lung cancer (SCLC) is typically characterized by more extensive local invasion and more frequent metastases compared with other subtypes. Although SCLC is sensitive to chemoradiotherapy, 25% of the patients with limited stage SCLC would meet local regional relapse. Although thoracic radiation had significantly improved local control, primary tumor recurrence is common in clinic. So far, we had little acquaintance of the local relapse details to help us to make progress in the thoracic radiation. To investigate the patterns of patients with local regional recurrence and the prognosis of primary tumor recurrence, we proposed this study. <h3>Materials/Methods</h3> We searched patients with pathological diagnosis of SCLC, with disease of limited stage, received systemic chemotherapy and thoracic intensity modulate radiotherapy at our center with available follow-up records between August 1^st, 2006 and May 31^st,2014. Patients with intrapulmonary recurrence or regional lymph nodes recurrence by the last follow up time, without diffused lung metastasis were selected. All the patients received involved field thoracic radiotherapy with dose of 2Gy per fraction per day. Data regarding patient demographics and treatments. The first local recurrent sites were recorded. Local regional relapse time was calculated from the first day of the treatment delivery to the diagnosis of primary tumor or regional lymph nodes. Overall survival was calculated from the first day of the diagnosis of local relapse to the death using Kaplan Meir Method. <h3>Results</h3> We identified 482 patients with a diagnosis of limited stage SCLC. Among these, 125 patients fulfilled the eligibility criteria. The median dose of radiotherapy is 60Gy. The median local relapse time was 12.97 months. Primary tumor recurrence, ipsilateral hilar and/or mediastinal lymph node recurrence, contralateral hilar and/or lymph node recurrence, and supraclavicular lymph node recurrence, were observed in 92 patients (73.6%), 49 patients (39.2%), 1 patient (0.8%) and 13 patients (10.4%), respectively. There were 26 patients with multisite local recurrence. Out-field relapse was observed in 6 patients (4.8%). The median follows up time was 34.7 months. After second line therapies, the median survival time for these patients diagnosed as recurrent disease was 10.5 months. Of the 92 patients with primary tumor recurrence, 25 patient received re-radiation and 39 patients also met distant metastasis. Median survival time of patients with primary tumor recurrence is slightly shorter than the others (9.9months vs. 12.0months). <h3>Conclusion</h3> For patients with limited stage SCLC who received chemoradiotherapy, primary tumor recurrence is still the leading course in local regional relapses and accompanied by worse survival. Accordingly, simultaneous integrated boost might be taken into consideration to primary tumor. Involved field radiation is reasonable with low out-field local recurrence.