Patient groups who particularly benefit from online adaptive radiotherapy
Patients who show significant anatomical variability during treatment or whose tumors are located close to critical organs benefit most from online adaptive radiotherapy (ART). These include, in particular:

Relevant volumetric and positional changes of both target and organs at risk are common. Online ART can improve target coverage and reduce radiation dose to sensitive structures such as salivary glands and skin. [1–3]

Especially in high-risk cases requiring pelvic radiation, the adaptive technique allows for smaller safety margins and thereby reduces toxicity to bladder and rectum. [4–5]

Daily adaptation helps manage the considerable variation in tumor and organ position caused by respiration, filling status, or peristalsis. This improves targeting accuracy and decreases radiation exposure to stomach, bowel, and other organs at risk. [4][6]

Particularly for sites with high mobility (e.g., stomach, mesentery) or those near critical structures. Online ART enables smaller treatment volumes and enhances safety. [7]

Especially in cases of large, residual, or recurrent disease where brachytherapy is not feasible. The online adaptive approach is advantageous when using small safety margins or hypofractionated regimens. [8]

In general, patients with pronounced anatomical changes, complex tumor locations, or close proximity to critical organs benefit the most from online adaptive radiotherapy. [1][4][9]