ASTRO issues guidelines for definitive, adjuvant radiation therapy in treatment of NSCLC

The American Society for Radiation Oncology issued new guidelines outlining the use of adjuvant and definitive external beam radiation therapy among patients with locally advanced non–small cell lung cancer.

George Rodrigues, MD, PhD, a clinician scientist and radiation oncologist at the Lawson Health Research Institute and London Health Sciences Center, and colleagues of the American Society for Radiation Oncology’s (ASTRO) panel — composed of 14 lung cancer oncologists from the U.S. and Canada — evaluated data from studies published between 1966 and 2013.

In a review of the guidelines — conducted by Bezjak and colleagues and published in Journal of Clinical Oncology — ASCO endorsed the ASTRO recommendations, calling them, “Clear, thorough and based on the most relevant scientific evidence.”

The topics addressed in the development of the guidelines on the use of definitive radiation therapy included the ideal radical radiation therapy dose fractionation for radiation therapy alone and for use in chemoradiation, as well as the ideal timing of radical radiation therapy with systemic therapy.

In the development of guidelines on adjuvant radiation therapy, researches sought to address the indications for postoperative adjuvant radiation therapy and preoperative neoadjuvant radiation therapy.

The panel reviewed 74 studies and formulated five questions on the role of definitive and adjuvant radiotherapy for locally advanced NSCLC, which is representative of nearly 25% of all lung cancer patients.

Further, the researchers identified 27 previously published clinical practice guideline documents that were relevant to the questions the panel asked as part of the review.

The answers to those questions became the published guidelines:

What is the ideal external beam dose-fractionation for the curative-intent treatment of locally advanced NSCLC with radiation therapy alone?

Data suggested that radiotherapy alone improved OS compared with chemotherapy or surveillance. However, there were some treatment-related adverse events from the radiotherapy, including esophagitis and pneumonitis. Yet, ASTRO recommends radiotherapy as a stand-alone radical treatment for patients with locally advanced NSCLC who are not eligible for a combination therapy at a minimum dose of 60 Gy.

What is the ideal external-beam dose-fractionation for the curative-intent treatment of locally advanced NSCLC with chemoradiotherapy?

The standard thoracic radiotherapy dose fractionation in this indication is 60 Gy administered as 2 Gy daily for 6 weeks. ASTRO indicated there is no association of any benefit, including OS, for a dose greater than 60 Gy.

What is the ideal timing of external-beam radiation therapy in relation to systemic chemotherapy for the curative-intent treatment of locally advanced NSCLC?

ASTRO recommends that when radiotherapy and chemotherapy are both used in treatment of locally advanced NSCLC, they should be used concurrently. If a patient cannot tolerate a concurrent regimen, radiation and chemotherapy should be administered sequentially, with chemotherapy first followed by radical radiation.

What are the indications for adjuvant post-operative radiotherapy for the curative-intent treatment of locally advanced NSCLC?

Post-operative radiotherapy for completely resected locally advanced NSCLC with N2 mediastinal disease is improved with local control, but does not improve OS. As such, ASTRO’s guideline indicated that post-operative radiotherapy is not recommended for patients with either N0 or N1 mediastinal disease. However, it is recommended for patients with either microscopic or macroscopic residual primary or nodal disease to improve local control.

When is neoadjuvant radiotherapy prior to surgery indicated for the curative-intent treatment of locally advanced NSCLC?

ASTRO’s guideline indicates there is no level 1 evidence that would recommend routinely using pre-operative neoadjuvant radiotherapy or chemoradiation for the management of locally advanced NSCLC. However it does provide information for ideal patient selection, operation type and dosage for those patients who would be selected for radiotherapy prior to having surgery.

“Radiation therapy is a central component of treatment protocols for patients with locally advanced NSCLC, with 5-year survival rates of approximately 26%,” Rodrigues said in a press release. “This guideline summarizes more than 35 years of clinical trial evidence to provide the best evidence-based guidance on radiotherapy to improve outcomes for this challenging patient population.” – by Anthony SanFilippo

References:

Bezjak A, et al. J Clin Oncol. 2015;doi:10.1200/JCO.2014.59.2360.

Rodrigues G, et al. Pract Radiat Oncol. 2015;doi:10.1016/j.prro.2015.02.013.

Rodrigues G, et al. Pract Radiat Oncol. 2015; doi:10.1016/j.prro.2015.02.012.

Disclosure: Rodrigues reports research funding from the Ontario Institute for Cancer Research. Beziak reports no relevant financial disclosures. Please see the studies for a complete list of all other researchers’ relevant financial disclosures.