Predictive factors for radiation pneumonitis in oesophageal cancer patients treated with chemoradiotherapy without prophylactic nodal irradiation

Abstract

Objective: The objective of this study was to identify clinical and dosimetric factors for the development of radiation pneumonitis (RP) among patients with oesophageal cancer treated with three-dimensional radiotherapy without prophylactic nodal irradiation.

Methods: 125 patients with oesophageal cancer had undergone dose-volume histogram (DVH) metrics and received chemoradiotherapy (CRT). Several clinical and dosimetric factors with regard to the lung were evaluated as predictive factors for the development of symptomatic RP.

Results: 26 patients (20.8%) developed symptomatic RP classified as greater than or equal to Grade 2. By univariate analysis, body weight loss, tumour length, Stage IV, response to treatment and all DVH parameters proved to be significant factors for the development of RP (p < 0.05). By multivariate analysis, Stage IV and all dosimetric factors were independent predictive factors for the development of symptomatic RP (p < 0.05). Recursive partitioning analysis indicated that V10 values of 24.8% or more and Stage IV were associated with higher development of RP (odds ratio 6.53).

Conclusions: Our study demonstrated that severe RP was also developed in patients treated with the minimal radiation field. Stage IV and the dosimetric factors were identified as independent predictive factors for symptomatic RP in oesophageal cancer patients treated with CRT without prophylactic nodal irradiation.

Figure 1

Recursive partitioning analysis using stage and all dosimetric factors as variables. In each terminal node, the upper row shows group number, the middle row shows the number of events (the development of symptomatic radiation pneumonitis) and patients and the bottom row shows the odds ratio with reference to all patients. MLD, mean lung dose.