Not ready for prime time
“Overall, this study conceptually is well designed as it is forward thinking and uses imaging to personalize radiation treatment, going to higher doses to active areas of disease based on FDG-PET imaging,” Arya Amini, MD, assistant clinical professor in the department of radiation oncology, City of Hope Comprehensive Cancer Center, Duarte, Calif., said in an interview.
Dr. Arya Amini
However, he cautioned, local failure is challenging to assess at 1 year because of radiation-induced changes. In fact, more than a quarter of study patients had scans that were not evaluable for this reason. Furthermore, rates of late cardiac toxicity and esophageal stenosis are unknown.
“Longer-term follow-up is needed as the current data does not support dose escalation in unresectable lung cancer, specifically stage III NSCLC, based on RTOG 0617,” Dr. Amini said. “However, the overall survival detriment from dose escalation in RTOG 0617 could have been due to poor radiation techniques and toxicities including cardiac side effects, which we now better understand. The PET-Boost trial focuses on delivering higher doses of hypofractionated radiation based on PET, which essentially leads to a smaller area getting a radiation boost, which, in turn, should have less side effects.”
“This area of work will continue to be more exciting as more tumor-targeting radiotracers can be utilized with PET,” he predicted. “One of the future avenues in radiation oncology is incorporating novel imaging modalities including tumor-specific radiotracers with PET scans, for example, to dose-paint disease, delivering higher doses to more active parts of the primary and lymph nodes, while reducing doses to less active areas, which potentially could lead to higher rates of local control with minimal side effects.”
The trial was sponsored by The Netherlands Cancer Institute. Ms. Cooke and Dr. Amini disclosed no conflicts of interest.
SOURCE: Lalezari F et al. ESTRO 2020. Abstract OC-0609.