Clinical implication of prophylactic irradiation of the ipsilateral hilum and mediastinum for clinical stage N0 non-small cell lung cancer

From 1981 to June 1990, 17 patients with clinical stage N0 non-small cell lung cancer were treated with definitive radiation therapy including prophylactic irradiation to the ipsilateral hilum and mediastinum. All patients had no obvious enlarged lymph nodes in the hilum and mediastinum on plain chest radiograph and conventional tomography. Three patients had T1 disease, 7 T2, 6 T3, and 1 T4. In patients with squamous cell carcinoma (11 patients), prophylactic irradiation of more than 40 Gy was delivered to the hilum/mediastinum as well as 60 Gy or more to the primary tumor. Prophylactic irradiation was given to patients with adenocarcinoma only when the primary tumor could be covered with small-sized radiation portals (8 patients). All patients with squamous cell carcinoma had no recurrence in the hilum and mediastinum, and the single patient with adenocarcinoma developed recurrence in the hilum. Considering that some patients with clinical N0 disease actually have pathological N1-2 diseases, prophylactic irradiation of over 40 Gy might be effective to control subclinical nodal metastases, at least in patients with squamous cell carcinoma. (author)