Involved-field irradiation therapy reduced toxicity without increasing loco-regional lymph node recurrence compared with elective nodal irradiation among patients with locally advanced esophageal cancer, according to prospective, randomized controlled study results presented at the ASTRO Annual Meeting.
Chemoradiation is the standard of care for locally advanced esophageal cancer. Elective nodal irradiation — or radiation to the tumor and lymph nodes, including uninvolved lymph nodes in the region around the tumor — is a radiation modality used to treat esophageal squamous cell carcinoma (ESCC); however, its use is controversial because it delivers higher irradiation and leads to higher rates of toxicity.
Tao Li, MD, PhD, vice chair of the department of radiation oncology at the Sichuan Cancer Hospital and Institute in Chengdu, China, and colleagues sought to evaluate the feasibility of reducing the nodal irradiation volume by comparing elective nodal irradiation to involved-field irradiation, which targets only the involved lymph nodes.
“Elective nodal irradiation is the most commonly used type of radiation therapy for treating esophageal cancer, but its toxicity and side effects have been criticized,” Li said in a press release. “Researchers have suggested decreasing the nodal irradiation volume with the use of involved-field irradiation, yet prior to this study its potential advantages had only been measured in smaller trials.”
The trial included 110 patients with esophageal cancer treated in several institutions across China — where the disease is much more prevalent than in the U.S. — between April 2012 and November 2014. All patients had inoperable, newly diagnosed stage II-III thoracic ESCC and were created with concurrent chemoradiotherapy and image-guided radiotherapy.
Researchers randomly assigned patients to receive elective nodal irradiation (n = 56) or involved-field irradiation (n = 54).
Toxicity and local-regional recurrence in the lymph nodes served as the study’s primary endpoint. Secondary endpoints included OS and distant failure.
After a median follow-up of 20 months, significantly fewer patients assigned involved-field irradiation experienced grade 2 or worse radiation esophagitis (20.4% vs. 26.8%; P = .001) and radiation pneumonitis (12.9% vs. 26.8%; P = .011).
There were no significant differences in rates of loco-regional lymph nodal recurrence (27.9% vs. 20.4%), distant failure (12.5% vs. 13%), 1-year OS (89.2% vs. 88.3%) or 2-year OS (64.2% vs. 55.6%) between the elective nodal irradiation and involved-field irradiation arms.
“We anticipated that involved-field irradiation could significantly decrease toxicity such as radiation pneumonitis and radiation esophagitis, but we were initially uncertain if involved-field irradiation might increase the loco-regional lymph nodal recurrence rates, distant failure and OS,” Li said in the release. “The mid-term results of our trial show that involved-field irradiation is an acceptable and toxicity-minimizing method of treatment for thoracic ESCC. This is a significant discovery for future esophageal cancer radiotherapy care.” – by Anthony SanFilippo
For more information: Li T, et al. Abstract 7. Presented at: ASTRO Annual Meeting; Oct. 18-21, 2015; San Antonio, Texas.
: HemOnc Today
was unable to confirm the researchers’ relevant financial disclosures at the time of reporting.