New guidelines from the American Society for Radiation Oncology (ASTRO) answer five key questions related to the role of definitive and adjuvant radiation therapy in treating locally advanced non-small cell lung cancer (LA NSCLC). Fourteen leading lung cancer oncologists in the United States and Canada were on a panel to create “Definitive and Adjuvant Radiotherapy in Locally Advanced Non-Small Cell Lung Cancer: An American Society for Radiation Oncology (ASTRO) Evidence-Based Clinical Practice Guideline.” These guidelines were approved by ASTRO’s Board of Directors last year before being released and then endorsed by the American Society of Clinical Oncology (ASCO) in “Definitive and Adjuvant Radiotherapy in Locally Advanced Non–Small-Cell Lung Cancer: American Society of Clinical Oncology Clinical Practice Guideline Endorsement of the American Society for Radiation Oncology Evidence-Based Clinical Practice Guideline.”
“Radiation therapy is a central component of treatment protocols for patients with locally advanced non-small cell lung cancer, with five-year survival rates of approximately 26 percent,” said George Rodrigues, MD, PhD, co-chair of the guideline panel and a radiation oncologist at London Health Sciences Centre in London, Ontario, in a news release from ASTRO. “This guideline summarizes more than 35 years of clinical trial evidence to provide the best evidence-based guidance on RT to improve outcomes for this challenging patient population.”
Each piece of the guideline aims to increase the rate of survival for the growing population of patients with LA NSCLC, who represent nearly 25% of patients with lung cancer. The guidelines were written using 74 studies of LA NSCLC in the literature and 27 published clinical practice guideline documents. This ensured the most appropriate clinical trial data were considered within the guidelines.
First, evidence presented in the guidelines suggest that radiation therapy can be safely used as a stand-alone treatment for LA NSCLC without chemotherapy if the proper dose is used. A minimum of 60 Gy is recommended and has been associated with improved survival for patients. However, side effects including esophagitis and pneumonitis may affect patients, but these are considered tradeoffs when individuals with LA NSCLC are not eligible for a combinatorial treatment approach. Moving on the question of using chemotherapy with radiation therapy, 60 Gy is also recommended for use. The standard dosing scheme is 2 Gy per day for six weeks. Studies that deliver more than 60 Gy do not provide evidence of added benefits, suggesting that 60 Gy with chemotherapy is adequate.
Timing of radiation therapy and systemic chemotherapy doses for LA NSCLC are also considered within the guidelines. Ideally, the two should begin simultaneously, but patients who cannot tolerate concurrent chemoradiation should receive sequential chemotherapy first and radical radiation treatment second. When surgery is involved, adjuvant post-operative radiation therapy is not typically recommended for curative-intent treatment of LA NSCLC patients with N0 or N1 mediastinal disease. However, those patients with N2 mediastinal disease were treated with post-operative radiation therapy. They showed improved local control of their disease, although their overall survival was not improved. For neoadjuvant radiation therapy or chemoradiation, there is no Level 1 evidence to recommend routine use of either before surgery for LA NSCLC.
Guidelines that address key questions are important for determining the appropriate treatment for patients with LA NSCLC. A variety of methods are used clinically, and each variation may or may not enhance patient outcome. Looking at the data presented, the panel of 14 clinicians compiled a set of recommendations to treat LA NSCLC.