Clinical and histopathological research on radiation therapy for early stage non-small cell lung cancer

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1) The effectiveness of high dose rate (HDR) endobronchial brachytherapy for roentgenographically negative carcinoma of the bronchus was prospectively evaluated. In our department, 14 lesions in 12 patients (11 male, one female) were treated with a combination of external radiotherapy and HDR endobronchial brachytherapy. Radiation dose was 40 Gy in 20 fractions for external radiotherapy. Endobronchial brachytherapy consisted of 10-25 Gy with 5 Gy/fr and the dose reference point varied 5-10 mm radius from the center of the applicator each according to a diameter of the bronchus. All patients had macroscopic complete response. Although the follow-up period ranged from 6 to 33 months with a median of 11 months, there were no patients with local progression. Radiation pneumonitis or other treatment-related complications have not been observed. These results suggested that the combination treatment of external radiotherapy and HDR brachytherapy can be used as curative intent for selected pa … More tients who have roentgenographically negative tumors limited to the bronchial wall without adjacent parenchymal extension or metastatic disease.2) The outcome of limited field irradiation for medically inoperable patients with peripheral stage I non-small cell lung cancer (NSCLC) was analyzed to discuss the elective irradiation of regional lymph nodes. There was no significant difference in disease-specific survival between ten patients with the elective regional irradiation and 26 patients without the regional nodal irradiation. Only one patient without regional nodal irradiation developed an isolated regional failure. High-dose limited field RT is justified for medically inoperable patients with peripheral stage I NSCLC. The regional nodal irradiation can be omitted in these pulmonary compromised patients because of the low regional relapse rate.3) The prognostic significance of nuclear p53 protein expression in survival and local control was investigated immunohistochemically in 36 patients with inoperable or unresectable non-small cell lung cancer who were treated with radiation therapy (RT). Response to RT was found in all p53 negative cases versus 72% in p53 positive cases (P<0.05). The 2-year survival rate for p53 negative cases was superior to that for p53 positive cases, although this difference was not statistically significant. The results suggested that p53 protein expression may be of predictive value on response to RT in non-small cell lung cancer.4) We designed the current prospective study to evaluate FDG PET in the detection of recurrent or residual tumors in patients who had undergone definitive radiation therapy (RT) for primary lung cancer. With a standardized uptake value (SUV) 【greater than or equal】 3 used for detecting recurrent lesion, sensitivity, specificity, and accuracy were 75%, 100%, and 89%, respectively. PET may be useful for distinguishing recurrent lesion from postradiation changes. Less