The American Society for Radiation Oncology (ASTRO) has issued evidence-based guidelines for stereotactic body radiation therapy (SBRT) in patients with early-stage non-small cell lung cancer (NSCLC; T1-2, N0). The guidelines, published in Practical Radiation Oncology, harmonize the variation in treatment for NSCLC clinical scenarios that include large, multifocal, recurrent, or centrally located tumors.
For all recommendations, the ASTRO task force urges clinicians to seek multidisciplinary review, consider clinical trial enrollment, and involve patients in treatment decisions. The systematic literature review incorporated 172 articles to support the recommendations. The guidelines are presented as multipart answers to 4 key clinical questions:
Medically operable patients should be evaluated by a thoracic surgeon in a multispecialty setting. In patients who have a “standard operative risk” — anticipated operative mortality of <1.5% — the task force does not recommend SBRT unless it is part of a clinical trial. Clinicians should counsel patients with high operative risk on the alternatives to surgery as well as the short- and long-term risks.
Medically inoperable patients should receive SBRT when their tumors are centrally located, >5 cm, and lack tissue confirmation, although the task force recommends obtaining biopsies whenever possible. In patients with multiple primary lung cancers (MPLC), the task force urges clinicians to seek a multidisciplinary consult and to differentiate the tumor from intrathoracic metastatic lung cancer with positron emission tomography/computed tomography and magnetic resonance imaging.
SBRT could be considered as a curative treatment option in synchronous and metachronous MPLC. In patients who have undergone pneumonectomy and have a primary tumor in their remaining lung, SBRT could be considered as a curative treatment in metachronous MPLC, although it may produce higher rates of toxicity than in patients with greater baseline lung capacity.
Medically inoperable patients with high-risk clinical scenarios who have tumors involving mediastinal structures or tumors near the chest wall should receive individualized SBRT based on available evidence. For tumors near the proximal bronchial tree, heart, and pericardium, ASTRO recommends delivering SBRT in 4 to 5 fractions. Clinicians should consult the current literature for treating patients with tumors near the esophagus. For tumors adjacent to the chest wall, SBRT may be considered, but patients need to be counseled on the common toxicities that may result.
Medically inoperable patients with recurring early-stage lung cancer requiring salvage therapy after conventionally fractionated radiation therapy, SBRT, and sublobar resection can receive SBRT as salvage therapy, although the quality of evidence supporting these recommendations is low. Salvage therapy should be individualized and patients need to be counseled about potentially fatal toxicities, particularly after having received conventionally fractionated radiation therapy.
The ASTRO guidelines were endorsed by the European Society for Radiotherapy & Oncology, the Royal Australian and New Zealand College of Radiologists, and the International Association for the Study of Lung Cancer.
Videtic GMM, Donington J, Giuliani M, et al. Stereotactic body radiation therapy for early-stage non-small cell lung cancer: executive summary of an ASTRO evidence-based guideline [published online June 5, 2017]. Pract Radiat Oncol. doi:10.1016/j.prro.2017.04.014