ASTRO Issued New Guideline on Use of SBRT in Early-Stage Lung Cancer

The American Society for Radiation Oncology (ASTRO) recently issued a new clinical guideline for the use of stereotactic body radiation therapy (SBRT) in patients with early-stage lung cancer.

“With longer life expectancies and more sophisticated diagnostic tools, we have seen a rise in the incidence of early-stage lung cancer, including among patients who are not able to undergo surgery or choose not to do so. SBRT provides an option for these patients, who otherwise may not have received curative, definitive treatment,” said Gregory M. M. Videtic, MD, co-chair of the task force that authored the guideline and a radiation oncologist at the Cleveland Clinic, in a press release. “Increasing access to this potentially life-saving treatment is essential to improve outcomes for the growing population of early-stage NSCLC [non–small-cell lung cancer] patients.”

ASTRO convened a task force to perform a literature review to address several key questions about the use of SBRT. In the guideline, SBRT was defined as stereotactic treatment delivered over 1 to 5 fractions.

First, the guideline looked at the use of SBRT as an alternative to surgery for subsets of patients with early-stage NSCLC that is medically operable. For standard-risk patients-stage I disease with anticipated risk of operative mortality of less than 1.5%-SBRT was not recommended as an alternative to surgery. However, the panel endorsed discussions about SBRT in patients with high-risk disease. Providers should inform patients at high risk that although short-term, treatment-related risks may be lower with SBRT, long-term outcomes are not yet well-established.

Second, the panel addressed the use of SBRT in medically inoperable patients with several different types of tumors. For centrally located tumors, the use of SBRT was deemed appropriate, but the panel noted that the associated risks of toxicity are dependent on the total dose and fractionation schedule. SBRT was conditionally recommended for patients with tumors larger than 5 cm who are not suitable for surgery. In patients unwilling or unable to undergo biopsy to confirm malignancy, SBRT can be considered. The panel recommended discussing these cases with a multidisciplinary tumor board. Finally, in patients with multiple primary lung cancers, SBRT can be considered as a curative treatment option.

Next, the guideline addressed the use of SBRT techniques tailored to tumor location. For example, for tumors located near mediastinal structures such as the trachea or the proximal bronchial tree, SBRT should be delivered in treatment schedules using 4 or 5 fractions. For tumors touching or invading the chest wall, SBRT is appropriate but patients should be counseled on the risk of grade 1/2 chest wall toxicity.

Finally, the panel reviewed evidence for the use of SBRT as salvage therapy for medically inoperable patients with recurrent early-stage disease. In patients with previous conventional radiation therapy, SBRT was recommended for carefully selected patients based on evidence demonstrating good local control with an acceptable toxicity profile. However, the panel recommended counseling patients on the potentially significant or fatal side effects. In patients with previous SBRT, repeat treatment is feasible in a highly selected patient population. Finally, for patients who have previous sublobar or limited resection, there is limited evidence; SBRT may be feasible but physicians should carefully weigh patient and disease characteristics.

“NSCLC is a complex disease, with a great deal of heterogeneity among patients. This guideline reinforces SBRT as the standard of care for medically inoperable patients, but it also examines the safety and efficacy of SBRT in less traditional clinical scenarios, such as patients with larger tumors or recurrent patients with early-stage disease,” reported Megan E. Daly, MD, co-chair of the task force and a radiation oncologist at the University of California Davis in Sacramento, in a press release.

A full copy of the guideline was published in Practical Radiation Oncology.