Results of the Definitive Radiation Therapy for the Early Stage (Stage I) Non-small Cell Lung Cancer

ABSTRACT

PURPOSE: To investigate the effectiveness and safety of definitive radiation therapy for Stage I non-small cell lung cancer patients who were medically inoperable or refused surgery. Material and M ethods: A retrospective study was conducted of 36 patients who received definitive radiation therapy for pathologically proven Stage I non-small cell lung cancer in the Department of Radiation Oncology, Asan Medical Center, between July 1989 and July 2003. Twenty three patients received conventional radiation therapy with a fraction size of 1.2~3.0 Gy, with a total dose of 50.0~70.2 Gy (CRT group). Thirteen patients received stereotactic radiosurgery with a fraction size of 10~12 Gy, with a total dose of 30~48 Gy using a Stereotactic Body Frame (Precision TherapyTM, SRS group). RESULTS: The two- and 5-year overall survival rates (OS) of all the patients were 79 and 44%, respectively. The two- and 5-year OS of the CRT and SRS groups were 43 and 53%, and 7 and 27%, respectively, but showed no statistically significant difference (p=0.5173). The two- and 5-year cause-specific survival rates (CSS) of the SRS group were superior to those of the CRT group (2YCSS: 100 vs. 70%, 5YCSS: 50 vs. 39%), but were not statistically significant (p=0.2086). The two- and 5-year local progressionfree survival rates (LPFS) of all the patients were 67 and 57%, respectively. The 5-year LPFS of the SRS group was superior to that of the CRT group (66 vs. 54%), but was not statistically significant (p=0.3937). The T-stage, tumor size, treatment method (CRT vs. SRS) and tumor dose did not affect the 2-year LPFS. Grade 2~3 radiation pneumonitis developed in 5 patients (14%), all in the CRT group. The omission of elective nodal irradiation (ENI) did not affect the incidence of Grade 2~3 radiation pneumonitis in the CRT group (ENI group 17%, no ENI group 25%, p=0.538). CONCLUSION: Definitive radiation therapy for Stage I non-small cell lung cancer patients that were medically inoperable or who refused surgery was considered effective and safe. Stereotactic radiosurgery was proven to be superior to that of conventional radiation therapy, although no statistically significant difference was shown. To investigate the optimal radiation dose and fractionation scheme of SRS, a prospective study, including more patients, is mandatory