Abstract Book

S752

ESTRO 37

EP-1378 Stereotactic body radiotherapy in an Australia centre for biopsy proven non-small cell lung cancer J. Croker 1 , S. Mincham 1 , C. Harper 1 , R. Chee 1 , E. Ng 1 , T. Lim 1 1 Fiona Stanley Hospital, Department of Radiation Oncology, MURDOCH, Australia Purpose or Objective To assess local control and survival in patients treated with stereotactic body radiotherapy in a single Australian institution for biopsy proven early stage non-small cell lung cancer. Material and Methods A retrospective analysis was undertaken of patients treated with stereotactic body radiotherapy for Stage I (T1N0M0 or T2N0M0) non-small cell lung cancer at a single Western Australian institution from late 2010 to mid-2015. All patients had attempted biopsy of treated lesions and cases were discussed at a lung cancer multi- disciplinary clinic prior to treatment. Patients were 4D-CT inverse planned and treated to a dose of 48Gy in 4 fractions (12Gy per fraction), 2 fractions per week over 2 weeks, utilising intensity- modulated radiation therapy, prescribed to the 65-82% isodose. Patients were followed post-treatment with 3-monthly follow-up imaging (CT and PET CT) until July 2017 or death. Local control, survival, cause of death information was collected. Frequencies, means, standard deviations for gender, smoking status, tumour stage, histology, location and local control were calculated and Kaplan- Meier survival analysis was undertaken. Results Forty four patients were treated from December 2010 to August 2015. The median age was 79 years (range 57-97). Fifty-two percent of patients were females and 48% males. The majority (86%) were present or past smokers. There was biopsy proven malignancy in 40 of 44 patients (91%). Adenocarcinoma (61%) was the most common pathology followed by squamous cell carcinoma (23%) and carcinoma, not otherwise specified (7%). Two-thirds of patients were staged as T1N0M0 (68%), 21% were T2N0M0 and 11% was treatment of recurrent disease. The median tumour size was 20mm (range 9-54mm). The most common location was right upper lobe (36%) followed by left upper lobe (32%). Local control was achieved in 96% of patients with only 2 patients having local failure. Nine patients (20%) had no residual mass seen at last follow-up imaging, whilst 33 (75%) had partial response or stable disease. Eleven patients (25%) failed distantly, with 6 patients failing in the distant lung and/or mediastinum and 5 patients failing both in the distant lung and outside the thorax. For the entire cohort, the overall survival rate was 61%. Median survival was 23 months and the 3 year overall survival rate was 65% (Figure 1). The 3 year disease-free survival rate was 41%. Six deaths were lung cancer related, eight due to non-lung cancer causes and three patients died of unknown causes .

localized stages (not candidates for surgery or SBRT) or locally advanced as sequential treatment after chemotherapy with good response in patients non candidates for concomitant radio-chemotherapy. Technique: 3D planning. Image control by portal image on a weekly basis. GTV: macroscopic primary tumour and lymph nodes> 1 cm or PET positive. CTV: GTV + margin of 6 mm in all directions. PTV: CTV + 10 -15mm. Patient criteria: ECOG 0-2 (ECOG 0-1 if> 75 years). Weight loss <10%. No serious comorbidities. Retrospective analysis of toxicity reported RTOG scale. Comorbidity simplified score scale (SCS). Kaplan-Meier and Chi-square tests were used. Results From March 2014 to march 2016, 46 patients were treated. Median age 74 years (49-84), <70 years (34.8%), >=70 years (65.2%). 43 men, 3 women. SCS <=7: 69%, >7: 31%. ECOG 0: 24%, ECOG1: 54%, ECOG2: 22%. Small-cell lung cancer 17.4%, NSCLC 82.6%. Stages IB-IV. Sequential 63%, Exclusive RT 37%. Acute toxicity 74%. Acute respiratory toxicity G0: 87%, G1:8.7%, G2: 4.3%, Acute Digestive toxicity, G0: 32.6%, G1: 45.7%, G2:19.6%, G3: 2.2%. Acute asthenia G0: 76%, G1:17.4%, G2: 6.5%. Median follow-up 14.3 months. 63% patients relapsed, 43.5% alive, 22 patients died from cancer, 4 died from non-tumour cause. 1 year OS: 64%, 2 years OS: 38%. 1 year DFS:45.9%, 2 year DFS:28%. No differences were seen in global toxicity regarding age (p=0.4) or SCS (p=0.32). No differences were seen in toxicity greater than G1 regarding age (p=0.3) or SCS (p=0.97).

Conclusion

•

In our experience hypofractionated radiation therapy in lung cancer with 3D technique has a good tolerance and is a safe treatment for elderly patients or with comorbidity in patients with ECOG<=2. No differences in acute toxicity, OS or DFS were seen depending on age or SCS. - This hypofractionated scheme provides the advantage of shortening the treatment to 4 weeks rather tan 6 weeks compared to conventional fractionation. A longer follow-up is required to have evidence of chronic toxicity and clinical outcomes.

•