Pulmonary complications in patients with complete remission after radio-chemotherapy for localized stage small-cell lung cancer

Abstract

Aim. The study aimed to analyse the effects of selected factors on the frequency of pulmonary complications in patientswith localized stage small-cell lung cancer (LS SCLC) in complete remission (CR) following radio-chemotherapy (RT-ChT).

Material and methods. Between 2000 and 2010, 286 patients with LS SCLC received RT-ChT. Treatment was given sequentially (157 patients — 54.9%) or concurrently (129 patients — 45.1%). According to the start of thoracic radiotherapy (RT) in relation to chemotherapy, the two groups were selected: RT started immediately after 1–2 cycles of chemotherapy (it was applied in 104 patients — 36.4%). The other 182 patients (63.4%) received RT after 3 or cycles of chemotherapy or later. Pulmonary complications were evaluated in patients with complete remission (CR) with a minimum follow-up period of 6 months. These complications found on radiological chest examinations were assessed according to classification proposed by the Fleischner Society. The severity of these pulmonary changes was assessed according to Common Terminology Criteria for Adverse Events (CTCAE). The frequency of lung complications and the influence of some therapeutic and clinical parameters to the development of pulmonary complications were evaluated. In addition the disease-free survival (DFS) rate was estimated in relation to factors that significantly influenced the frequency of pulmonary complications.

Results. A total of 187 patients (65.4%) achieved CR following RT-ChT. For 152 patients (81.3%) the duration of follow-up was at least 6 months. Pulmonary complications were observed in 132/152 patients (86.8%). These patients accounted for 70.6% of those with CR. Pulmonary fibrosis was observed in 91 patients (48.7%) and these patients accounted for 48.7% of those with CR. Other signs of lung complications were ground-glass opacities (74 patients — 56.1%) and interlobular septal thickening (24 patients — 18.2%). These changes were either accompanied by fibrosis (54 patients) or appeared independently (41 pts.). The incidence of pulmonary complications significantly correlated with the schedule of RT-ChT (93.3% vs 80.5% for concurrent vs sequential) and the beginning of thoracic RT (95.6% vs 79.8% for RT after 1–2 cycles ChT vs RT after 3 or later). The significant differences related to maximum lung dose, mean lung dose and V20 were demonstrated after taking into account the schedule of RT-ChT and the start of thoracic RT.

Conclusions. In patients with LS SCLC the schedule of radio-chemotherapy and timing of thoracic radiotherapy have a significant impact not only on the results of treatment (disease-free survival rate) but also on the incidence of pulmonary complications in patients with LS SCLC.