Abstract 94P
Background
Stereotactic radiotherapy (SBRT) remains a viable option for early stage inoperable non small cell lung cancers (NSCLC). Multitude of delivery platforms and motion management devices been in practice with their own pros and cons. We report the departmental prospectively maintained database for early stage (T1-2a,N0M0 8th edition) NSCLC treated by SBRT with deep inspiratory breathold (DIBH) and robotic couch correction.
Methods
20 patients were analysed during the process between Jan 2018 to July 2021. Median age was 60 years with male preponderance. Smoking remained predominant and comorbidities (diabetes, hypertension). All cases were discussed in joint clinic and deemed inoperable by thoracic surgeon in view of poor cardiac functions or uncontrolled comorbidities. All were staged by PETCT scan, pulmonary function test (PFT). SBRT planning training done by DIBH 2-3 days prior and contrast enhanced 1.25mm planning scans were obtained with free, ABC (actiev breath co-ordinator) DIBH. Contouring done as per guideline for both primary and organs at risks. Dose prescription were based on peripheral (48 Gy/4 fractions) or central (50-56 Gy/5-7 fractions). SBRT were alternate days. Pre treatment, intra treatment CBCT were acquired and corrections applied with robotic couch Hexapod. Follow up every 3 months with PETCT around 3-6 months from treatment and PFT.
Results
With median follow up of 2 years, the local control and regional control were 90% and 80% respectively. 6 patients developed distant metastases. the distant metastases were more in T2 patients and with squamous histology. There were minimal adverse events with fatigue most common in acute and radiation penumonitis (grade 1-2) in late. The average treatment time for ABC-DIBH was 45 minutes. There were no grade 3 events in terms of chest wall or bronchial involvement. Surgical salvage required in 3 cases and systemic chemotherapy and immunotherapy for 5 cases.
Conclusions
ABC-DIBH based SBRT seems feasible and well tolerated. The results are encouraging with few number of patients. The concerns of longer treatment duration with DIBH, intra treatment changes, T2 tumors, squamous histology are challenging.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.