ESTRO 2021 Abstract Book

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ESTRO 2021

Fig. 1. Overall survival in two independent test cohorts.

Conclusion We developed a hybrid deep learning-based model that utilized both clinical and image features for 2-year overall survival prediction for ES-NSCLC patients that underwent SBRT. Such a model has the potential to identify patients with increased mortality risk and guide clinical decision making. PH-0491 Clinical stereotactic ablative body radiotherapy on patients with early-stage inoperable lung cancer R. Yeo 1 , P. Nariyangadu 1 , N. Shah 1 , Y. Tsang 1 1 Mount Vernon Hospital, Radiotherapy, London, United Kingdom Purpose or Objective This study aims to examine the efficacy of SABR for this patient cohort at our institution in terms of overall survival (OS), progression free survival (PFS) and post radiotherapy (RT) toxicity. Materials and Methods A retrospective review of all patients diagnosed with early-stage lung cancer (T1-2N0M0) who were treated with a dedicated robotic stereotactic RT machine at our institution was conducted. All patients were treated with image guided RT under free breathing, monitored by real time motion tracking. OS and PFS was calculated using Kaplan-Meier statistics and the post RT toxicity data was scored following the CTCAE v4.0 protocol. A subgroup analysis of prognostic factors on OS and PFS was performed based on patients’ age, gender, tumour laterality, T stage and baseline lung function. A Mantel-Cox log-rank analysis was used to assess any statistically significant differences in OS and PFS between these groups. Results Between January 2016 to December 2018, this study included 77 patients with a median age of 79 years (range 47.0-94.0) and median follow up of 20.9 months (range 9.7-47.3). Estimated overall median OS was determined to be 20.9 months with the OS of 85.7% and 61.8% at 1 and 2 years respectively. No statistically significant differences in OS were found when comparing the subgroups of age, tumour laterality, T stage and baseline lung function apart from gender (p<0.05). The PFS at 1 and 2 years were 85.5% and 73.7%. Of these, only 7 (9.2%) patients were locally recurred. There were no statistically significant differences in PFS among all factors apart from T stage (p<0.05). Pre-treatment baseline FEV1 function was recorded in 60/77 (78%) patients – with an FEV1 range of between 0.49 to 2.83 (Median 1.78). Although 32 patients presented with an FEV1 of <1.2L, there was no statistically significant impact on OS or PFS. The vast majority of patient tolerated the treatment well with the most common acute side effects of grade 1 fatigue reported (45.3%), followed by shortness of breath (22.7%). Only 3 patients developed Grade 2 side effects and only 1 instance of Grade 3 chest infection was noted.

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Conclusion The use of SABR in the treatment of patients diagnosed with early-stage inoperable lung cancer has shown promising treatment outcomes, despite the fact that the patients were with a median age of 79 years and limited baseline lung functions.