P2.16-17 Hypo-Fractionated Accelerated Radiotherapy in Central Early Non-Small Cell Lung Cancer: Leeds Cancer Centre Experience

Centrally located early stage lung cancers in patients who are unfit for surgery and stereotactic ablative body radiotherapy (SABR) are routinely treated with radical radiotherapy. There are no standard dose regimens but evidence seems to favour acceleration. We present the outcomes of a moderately hypo-fractionated accelerated dose regimen of 50Gy in 15 fractions (BED (a/b=10) corrected for time = 58.85Gy) from a single centre in the UK. Electronic case notes and radiotherapy records of lung cancer patients treated between January 2014 to December 2016 were retrospectively reviewed. Adult Comorbidity Evaluation-27 (ACE-27) score was used to evaluate comorbidities. Survival outcomes were estimated using Kaplan-Meier curves and compared using log-rank test. Fifty-three patients were treated with 50Gy in 15 fractions with a median age of 74.0 years (IQR: 69.5–79). 4 patients had a poor WHO PS of 3. Thirty-seven (69.8%) were females. A similar number had Grade 2 or 3 ACE-27 score while one had Grade 0. Forty-six patients were stage I, whilst four and three patients were stage II and III respectively. Thirty-seven (70%) patients had a radiological diagnosis. The treatment was well tolerated, 90-day mortality rate after radiotherapy was 3.8% (n=2). Grade 2 pneumonitis was seen in 5 patients while no grade 3 or 4 pneumonitis was observed. At the time of cut-off for analysis, the median follow-up was 20.2 months. The median progression-free survival (PFS) and overall survival (OS) were 18.5 months (95% CI 12.2–24.8) and 28.2 months (95%CI 14.4–42.1) respectively. The estimated 1 and 2 year PFS were 62.3% and 41.3% respectively and OS were 77.4% and 56.6% respectively. Only PS significantly impacted survival on univariate analysis, while PS and ACE-27 both were shown to have significant effect on multivariate analysis. Of the nineteen patients who relapsed, 4 (7.5%) had infield recurrence, 10 had out-of-field lung recurrence and the rest had distant metastases. One patient underwent salvage surgery. 6 patients received further radical therapy with 3 each being treated with conventional and SABR. This moderately hypo-fractionated accelerated radiotherapy regimen for central early stage lung cancer seems similar in efficacy but is associated with significantly less toxicity when compared to SABR.