The effect of postoperative external beam radiation in MO non-small cell lung cancer resected with curative intention was evaluated in a randomized trial. In 155 patients (121 males, 34 females; mean age: 59 years) 105 lobectomies, 12 bilobectomies and 38 pneumonectomies with radical lymph node dissection to the contralateral side were carried out. Histology revealed squamous cell (n = 68), adeno- (n = 53), large cell (n = 21), adenosquamous (n = 6) or bronchioloalveolar type (n = 7) carcinomas. The pathologic stages T1 (n = 38), T2 (n = 89), T3 (n = 28); NO (n = 39), N1 (n = 67), and N2 (n = 49) were evenly distributed between the two treatment groups: group A (72 patients) had no further oncologic treatment, while group B (83 patients) had external beam radiation to the mediastinum (50-56 Gy, 8 or 23 MeV photons, 2 Gy/day, 5 days a week) beginning 4 weeks after the operation. The overall 5-year survival rate of the whole collective was 24.1% without any significant difference between the radiotherapy group B (29.7%) and the control group A (20.4%) (log-rank test: P > 0.05). The overall 5-year recurrence-free survival rate was 20.1%, with no difference between groups B and A (radiotherapy: 22.7, controls: 15.6%, long-rank test: P > 0.05). There was no difference in the incidence of distant metastases (external beam radiation: n = 32; controls: n = 38). The rate of local recurrences at the bronchial stump or in the mediastinum, however, was significantly reduced in the radiotherapy group (n = 5) compared with 17 in the controls (P < 0.01 chi-square test). A multivariate analysis confirmed the independent influence of postoperative radiotherapy on the incidence of local recurrence. External radiation of the mediastinum in radically resected non-small cell lung cancer reduces the risk of local recurrence, but has no influence on distant metastastic spread and overall survival. Smolle-Juettner, Mayer, Pinter, Stuecklschweiger, Kapp, Gabor, Ratzenhofer, Hackl, (1996). "Adjuvant" external radiation of the mediastinum in radically resected non-small cell lung cancer. European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, 1996 ;10(11):947-50; discussion 951. https://www.ncbi.nlm.nih.gov/pubmed/8971505