Implementation of Lung Stereotactic Ablative Radiotherapy at a Regional Cancer Centre.

BACKGROUND

For patients with inoperable Stage I (T1-T2, N0, M0) non-small-cell lung cancer, stereotactic ablative radiotherapy (SABR), also known as stereotactic body radiation therapy (SBRT), has demonstrated survival outcomes similar to surgery. Lung SABR is a technically challenging means of delivering precise, high-dose radiation to a small tumor volume. At many cancer centres, the widespread use of SABR is impeded by the complexity of the implementation process. This study will aim to provide a detailed guide to the steps involved in delivering lung SABR in a reliable and efficient manner.

PROCESS

The execution of this intricate treatment program at our cancer centre required the collaboration of a multidisciplinary team. Input from several professionals within radiation oncology was necessary, including medical physicists, dosimetrists, radiation therapists, nurses, and radiation oncologists. Expert guidelines have been developed which give careful consideration to each step of the process, including 1) reliable and reproducible patient immobilization, 2) a method to account for tumor and organ motion, 3) the use of multiple treatment fields to deliver highly conformal radiation dose with a rapid dose fall off, 4) daily imaging that allows for repositioning from simulation to treatment, 5) accurate and precise dose-calculation algorithms, and 6) a vigorous quality assurance program. Lung SABR was introduced at our centre in 2007 and thus far 92 patients have been treated. There are currently three treatment machines capable of performing this procedure.

BENEFITS/CHALLENGES: Patient immobilization through the use of body cushions, accurate tumor and organ delineation via the use of four-dimensional computed tomography simulation, development of firm treatment planning guidelines, treatment verification using cone beam computed tomography, and a robust quality assurance program have all been instrumental in ensuring the safe and effective delivery of lung SABR. However, the process was laden with challenges, from delineating the optimum immobilization technique that balances patient comfort and motion, to introducing ways of making novice staff comfortable with a new method for treatment verification.

CONCLUSIONS

There are outcome and toxicity data being collected on patients undergoing lung SABR at our cancer centre. This will serve as a self-assessment tool for our implementation process. Moreover, as future indications for SABR change, this initial implementation step will serve as a framework on which to continue building comprehensive guidelines.