The Overall Survival of Non-Small Cell Lung Cancer Patients Group pN2 after Radical Surgery and Postoperative Radiotherapy

Purpose: Comparative analysis of the overall survival (OS) in different subgroups of the patients with non-small cell lung cancer (NSCLC) with affected mediastinal lymph nodes (pN2) after surgical and combined treatment using postoperative radiotherapy (PORT). Material and methods: A comparative assessment of the overall survival of 243 patients with NSCLC stages IIIA, IIIB (pT1–4N2M0) was carried out: the I group – 79 patients after radical (R0) surgical treatment (lobe/bilobectomy, pulmonectomy with ipsilateral mediastinal lymph node dissection) and the second group – 164 patients after the combined modality therapy with the same volume of surgery and postoperative radiotherapy in the mode of hypofractionation (daily dose 3 Gy, 5 times a week, TD = 36–39 Gy (EQD2 = 43.2–46.8 Gy, α/β = 3) or classical fractionation (2 Gy, 5 times a week, TD = 44 Gy). We analyzed subgroups of men and women, patients younger than 60 years and older, with central and peripheral cancer, squamous cell carcinoma and adenocarcinoma, with different gradation of tumors according to the criterion T (pT1–4). Results: In the compared groups, 2-year and 5-year OS was significantly higher in the PORT group (62.4 and 31.6 vs 44.8 % and 12.3 %, p = 0.0028), at the expense of male patients (62.4 and 31.6 % vs 44.8 and 12.3 %, p = 0.0028), patients with central cancer (59.2 and 43.7 % vs 36.3 % and n/a, p = 0.0023), patients with squamous cell carcinoma (64.0 % and 43.1 % vs 42.3 % and 6.7 %, p = 0.0006), patients older than 60 years (74.8 and 46.2 % vs 45.1 % and n/a, p = 0.007). A more detailed analysis revealed that PORT significantly increased 2- and 5-year OS in the central squamous cell carcinoma of the lung (67.3 and 53.0 % vs. 33.3 and 0 %, respectively, p = 0.0013), and in pT3–4 tumors (2-year OS 57.1 vs. 36.4 %, respectively, p = 0.0102). There was only a tendency of increasing OS after the PORT in T2 tumors (5-year OS 31.1 vs 15.4 %, respectively, p = 0.1319). In T1 tumors, no differences in OS were found, possibly due to the small number of cases (27). In peripheral squamous cell carcinoma there was a statistically insignificant increasing of 5-year OS – 7 %. There was no significant differences in OS survival were obtained in central and peripheral lung adenocarcinoma between the I and II groups. Conclusion: In the patients with non-small cell lung cancer pN2, radically operated (R0) in the volume of lobe/bilobectomy, pulmonectomy with ipsilateral mediastinal lymph node dissection, PORT can be recommended for central squamous cell carcinoma pT1–4. In the patients with peripheral squamous cell carcinoma, PORT can be discussed for the patients with individually assessed high risk of the locoregional relapse. PORT, within the scope of irradiation and total doses used in this study, has no age restrictions. The feasibility of PORT for radically operated patients with pN2 lung adenocarcinoma requires further study.