Use of tumor match and adaptive radiotherapy (RT) in patients undergoing treatment for non-small cell lung cancer (NSCLC) resulted in decreased adverse events while maintaining loco-regional control, according to the findings of a recent study published in Radiotherapy & Oncology.
“On modern treatment machines, the patient anatomy can be monitored daily by cone-beam computed tomography (CBCT),” study authors explained. “In case of dose deterioration, the treatment plan can be adapted (adaptive RT). By virtue of CBCT-mediated patient setup according to the tumor location (tumor match) as opposed to bony anatomy and adaptive RT, geometric uncertainties can be largely eliminated and thus, the total irradiated volume can be reduced.”
In this retrospective study, researchers reviewed outcomes associated with the use of tumor match and adaptive RT based on daily CBCT scans in patients with NSCLC treated with definitive chemoradiotherapy. The study included 184 patients treated before tumor match and adaptive RT were adopted and 255 patients treated after.
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Concomitant chemotherapy was given more frequently among patients treated with adaptive RT (78% vs 64%; P <.001).
Median planning target volumes decreased from 456 cm3 before adaptive RT to 270 cm3 after adaptive RT was adopted (P <.001). This significantly reduced the mean doses to the lungs and heart (P <.001 for both).
“The significant reduction in heart and lung doses may also contribute to a reduction in other, unattributed toxicity-related deaths in a population with frequent heart and lung comorbidities,” the researchers wrote.
At 9 months, radiation pneumonitis was significantly decreased in patients treated with adaptive RT compared with those treated pre-adaptive RT. This included symptomatic pneumonitis (50% to 20%), severe pneumonitis (21% to 7%), and lethal pneumonitis (6% to 0.4%; P <.001 for all).
Additionally, the 2-year progression-free survival rate was higher after adaptive RT was adopted (30% vs 22%), and median overall survival also increased (20 months to 28 months).
“The observed increase in progression-free survival and overall survival is likely a composite of several factors, consisting of fewer patients with progression of disease and lower incidence and severity of radiation pneumonitis,” the researchers noted. They added that this survival benefit was seen despite a “somewhat poorer pre-treatment patient performance status” among patients treated with adaptive RT.
Reference
Moller DS, Lutz CM, Khalil AA, et al. Survival benefits for non-small cell lung cancer patients treated with adaptive radiotherapy. Radiother Oncol. Published online February 1, 2022. doi:10.1016/j.radonc.2022.01.039
