[Results of radiation therapy for limited small-cell lung cancer]

Results of radiotherapy were reviewed in 68 patients with limited small-cell lung cancer from the aspect of local control. Thirty-one patients achieved CR (46%), while the other 31 remained at PR. The 1-, 2-, 3-, and 5-year cumulative survival rates were 57%, 28%, 21%, and 16%, respectively, for 15 months in MST. Thirty-six patients developed local recurrence (53%) and 46 had distant metastasis (68%). The thirty-one patients with CR had a 43% 2-year-survival rate and 23 months in MST. The remaining 37 patients (PR + NC) had respective figures of 13% and 13 months (p < 0.025). There was no statistically significant difference between radiation dose and local thoracic failure among the patients. Of the 31 patients with CR, 28 had achieved CR at 45Gy (17 received 55Gy or more, and 11 less than 55Gy). In the former, the local control rate, 2-year-survival and MST were 94%, 53% and 44 months, while in the latter these were 45%, 27% and 17 months, respectively. Thirty-five patients were irradiated by the shrinking field technique according to tumor reduction; however, this technique did not influence the treatment results. To obtain better results, it is first necessary to achieve CR at initial chemo-radiotherapy. As to irradiation, randomized trials between 50Gy and 60Gy would require patients with CR at 45Gy.