The American Society for Radiation Oncology (ASTRO) and the European Society for Radiotherapy & Oncology (ESTRO) provided advice on the use of definitive local therapy—including radiation and surgery—to treat patients with oligometastatic non–small cell lung cancer (NSCLC), according to new guidelines published by Iyengar et al in Practical Radiation Oncology.
The new guidelines also emphasized the need for a multidisciplinary approach to making treatment decisions for this patient population.
Background
Treatment for oligometastatic NSCLC has historically involved systemic therapy such as chemotherapy or immunotherapy, with local therapy given only for palliation and symptom relief. A growing body of research, however, indicates that definitive local therapy may be applied to all disease sites for durable tumor control and improved survival outcomes.
“Oligometastatic NSCLC is a phase in lung cancer development that may offer us new opportunities to improve patient outcomes, because it typically is more treatable than widely metastatic cancer,” explained lead study author Puneeth Iyengar, MD, PhD, Associate Professor of Radiation Oncology, Chief of Lung Radiation Oncology Service, and Vice Chair of Strategy and Program Development at the University of Texas Southwestern; and Co-Chair of the guideline task force. “The research on local therapy for oligometastatic cancer is still at a relatively early stage, but we already see indicators of potential benefits for patients. Adding local therapy to systemic therapy may lead to more durable cancer control, potentially improving progression-free survival, overall survival, and quality of life,” he added.
“Despite the widespread enthusiasm in the field of oligometastatic disease, the quality of evidence supporting the integration of definitive local therapy into a multimodality treatment strategy is still lower as compared to indications such as locally advanced NSCLC. To compensate for this lack of highest-quality evidence, recommendations of this guideline were established by a broad consensus involving experts from ASTRO and ESTRO, colleagues from the fields of thoracic surgery and medical oncology, and a patient representative,” highlighted senior study author Matthias Guckenberger, MD, Professor and Chair of the Department of Radiation Oncology at the University Hospital Zurich and Co-Chair of the guideline task force.
Overview of the New Guidelines
In the new guidelines, investigators addressed patient selection, treatment planning, and delivery techniques for definitive local therapy to treat patients with oligometastatic NSCLC. They emphasized the need for patient-centered, multidisciplinary decision-making and created algorithms on the optimal clinical scenarios for the different types of local therapy available to this patient population.
Among the key recommendations were:
- The integration of definitive local therapy was recommended only for patients with five or fewer distant extracranial metastases and only when technically feasible and clinically safe for all disease sites. Definitive local therapy—in addition to standard-of-care systemic therapy—was conditionally recommended for carefully selected patients with synchronous oligometastatic, metachronous oligorecurrent, induced oligopersistent or induced oligoprogressive conditions in patients with extracranial metastases.
- Radiation and surgery were the only recommended modalities for definitive local treatment of patients with oligometastatic NSCLC. Radiation may be preferable when treating multiple organ systems or when the clinical priority is to minimize breaks from systemic therapy. Surgery may be preferable when large tissue sampling is needed for molecular testing to guide systemic therapy. Highly conformal radiation and minimally invasive surgical techniques were strongly recommended to minimize side effects.
- The investigators also addressed sequencing and timing for combined systemic and local therapy, emphasizing upfront, definitive local treatment for symptomatic metastases. For asymptomatic patients with synchronous disease, investigators suggested at least 3 months of standard-of-care systemic therapy before starting definitive local therapy.
- The investigators further outlined optimal staging, radiation dosing, treatment planning, and delivery techniques. Hypofractionated radiation therapy or stereotactic body radiation therapy were preferred modalities when appropriate. In addition, the investigators stressed the importance of proper imaging to diagnose patients with oligometastatic NSCLC—as well as pathologic confirmation of metastases—and recommended that physicians consult guidelines from the National Comprehensive Cancer Network and the European Organisation for Research and Treatment of Cancer.
- The investigators advocated incorporating local therapy into standard treatment paradigms for patients who experience recurrent or metastatic disease following definitive local therapy for oligometastatic NSCLC.
Conclusions
The investigators noted that although intracranial metastases were not included in their new guidelines as a result of the additional complexity involved in local therapy decisions for intracranial tumors, guidelines for brain metastases were published by Gondi et al in Practical Radiation Oncology in 2022.
“[A] significant effort must be taken to ensure that the decisions regarding the use of local therapies for oligometastatic NSCLC be applied equally across all patients to avoid any health disparities,” the investigators concluded.
Disclosure: The new guidelines were endorsed by the Royal Australian and New Zealand College of Radiologists and the Canadian Association of Radiation Oncology. For full disclosures of the study authors, visit practicalradonc.org.
