Prognostic role of texture analysis in lung cancer treated with stereotactic ablative radiotherapy (SABR)

Background

Stereotactic ablative radiotherapy (SABR) is widely used in lung cancer primary treatment. The aim of present study is to evaluate the texture analysis as a predictive factor of treatment response.

Methods

This single center retrospective study included fifty-six consecutive patients (January 2011 – December 2014) with early stage lung cancer (T1-2a, N0) treated with SABR. The diagnostic CT DICOM images pre- and post- SABR were collected and analysed with an homemade ImageJ macro and typical texture analysis parameters were evaluated: mean (m), standard deviation (sd), skewness(sk), kurtosis (k), entropy (e) and uniformity (u). We analyzed progression free survival with modality of lung progression (PFS in-field and PFS out-field) after treatment and overall survival (OS), calculated with Kaplan-Meier method.

Results

During the observation period 15 patients (26,8%) showed evidence of recurrence, divided in recurrence “in-field” in 9 patients (16,1%), and “out of field” recurrence in 11 patients (19,6%). Five patients developed both “in field” and “out of field” recurrence; 14 patients (25%) died. Pre SABR parameters Entropy (e) and uniformity (u) were significantly associated with PFS “in field” (p:0,030), whereas kurtosis (k) was significantly associated with PFS “out of field” (p:0,031) and Mean (m) was significantly associated with OS (p 

Conclusions

Our results appear to be very promising since the knowledge of the predictive factors of SABR could drive the selection of the best treatment in these patients (i.e. dose increasing in the patients at higher risk? Concurrent chemoradiation? Intensified follow up?). Further studies on large patient series are needed to best estimate the present preliminary data.

Clinical trial identification

Legal entity responsible for the study

Unit of Radiation Oncology, University Hospital of Siena

Funding

Unit of Radiation Oncology, University Hospital of Siena

Disclosure

All authors have declared no conflicts of interest.