Patients with early-stage non–small cell lung cancer, particularly those whose tumors are inoperable and who have limited treatment options, should undergo stereotactic body radiation therapy, according to guidelines from the American Society for Radiation Oncology.
Stereotactic body radiation therapy (SBRT) — which delivers ablative radiation doses in one to five fractions with highly conformal techniques to spare healthy tissues surrounding the tumor — has become standard of care for medically inoperable, peripheral early-stage NSCLC; however, its use varies for other clinical scenarios, including large, multifocal, recurrent or centrally located tumors.
A patient receives stereotactic body radiation therapy (SBRT) to treat lung cancer.
American Society for Radiation Oncology/Adam Donohue
“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,” Gregory M.M. Videtic, MD, co-chair of the task force that authored the guideline and a radiation oncologist at Cleveland Clinic, said in a press release. “SBRT provides an option for these patients, who otherwise may not have received curative, definitive treatment. Increasing access to this potentially life-saving treatment is essential to improve outcomes for the growing population of early-stage [patients with] NSCLC.”
Videtic and task force members conducted a literature review of 172 articles published from January 1995 through August 2016. The goals included to evaluate available data on the application of SBRT for operable patients; the appropriate use of SBRT in tumors that are centrally located, large, multifocal or unbiopsied; individual tailoring of SBRT in high-risk clinical scenarios; and SBRT as salvage therapy after recurrence.
For medically operable, early-stage (T1-T2, N0) patients, the guidelines state those who are standard risk — with an anticipated risk for operative mortality of less than 1.5% — should not undergo SBRT as an alternative to lobectomy with systemic mediastinal lymph node evaluation. However, those who are high risk — or who have a great risk for surgical morbidity or mortality or who cannot tolerate lobectomy — should discuss SBRT as an alternative treatment.
The task force based their recommendations for medically inoperable patients on the following tumor characteristics:
- Centrally located tumors — SBRT is appropriate, but should be delivered in four to five fractions due to toxicity risks, with special consideration given for its use on tumors involving critical structures like the airways, heart and esophagus;
- Large tumors — SBRT is conditionally recommended for tumors larger than 5 cm;
- Nonbiopsied patients — SBRT can be considered for patients unwilling or unable to undergo biopsy but who have appropriate imaging studies to support a cancer diagnosis; and
- Multiple primary lung cancers/pneumonectomy — SBRT can be considered as a curative-intent option for patients with a history of previously resected lung cancers or who received a pneumonectomy and who now have a new primary tumor after consideration of risk for higher lung toxicity rates.
The task force members also note that use of SBRT should be individually tailored in patients with tumors near critical structures to minimize toxicity. Patients with tumors that touch the trachea or proximal bronchial tree, or that are near the heart of pericardium, should undergo SBRT in four or five fractions. Patients with tumors near the esophagus also should undergo these treatment schedules, although the task force noted data for these patients are limited.
SBRT also is an option for patients with tumors touching the chest wall, although patients should receive information about the risk for grade 1 to grade 2 chest wall toxicity. SBRT is endorsed for tumors that invade the chest wall, because it appears effective without increasing toxicity.
The task force adjusted their recommendations for medically inoperable patients with recurrent disease based on their treatment history:
Previous conventional radiation therapy — SBRT is conditionally recommended for carefully selected patients after they are counseled on the potential for substantial, fatal toxicity and risk for regional and distant failure;
Previous SBRT — SBRT can be repeated in a highly selected patient population after a careful assessment of evidence-based patient, tumor and treatment factors, although data are limited for this group; and
Previous sublobar/limited resection — SBRT may be feasible, but these patients should be considered on an individual basis.
“NSCLC is a complex disease, with a great deal of heterogeneity among patients,” Megan E. Daly, MD, co-chair of the task force and a radiation oncologist at University of California, Davis in Sacramento, said in the release. “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.” – by Alexandra Todak
Disclosure: Videtic and Daly report no relevant financial disclosures. Please see the full guidelines for a list of all other authors’ relevant financial disclosures.