Significance of postoperative irradiation for stage III lung cancer

The significance of postoperative irradiation for stage III lung cancer was analyzed in 30 patients. Radiation was given to 15 of the patients and the remaining 15 did not receive any radiation therapy following surgical intervention. A total dose of 40 to 70 Gy was given to the radiation group with a fraction dose of 2 Gy five times a week using cobalt 60 gamma-ray or linac 10 MV X-ray. There was no significant difference of survival time between these two groups. However, in analyzing modes of operation, radiation seemed to improve the survival rate in patients who underwent curative or relatively curative operations (P = 0.1), while the patients who underwent non-curative operations did not receive any benefit from the postoperative irradiation. Some reasons for the ineffectiveness in cases of non-curative operation are discussed.