Multi-centre real-world validation of automated treatment planning for breast radiotherapy

Purpose: To present the results of the first multi-centre real-world validation of autoplanning for whole breast irradiation after breast-sparing surgery, encompassing high complexity cases (e.g. with a boost or regional lymph nodes) and a wide range of clinical practices. Methods: The 24 participating centers each included 10 IMRT/VMAT/Tomotherapy patients, previously treated with a manually generated plan ('manplan'). There were no restrictions regarding case complexity, planning aims, plan evaluation parameters and criteria, fractionation, treatment planning system or treatment machine/ technique. In addition to dosimetric comparisons of autoplans with manplans, blinded plan scoring/ranking was conducted by a clinician from the treating center. Autoplanning was performed using a single configuration for all patients in all centres. Deliverability was verified through measurements at delivery units. Results: Target dosimetry showed comparability, while reductions in OAR dose parameters were 21.4 % for D mean , 16.7 % for ipsilateral lung D mean , and 101.9 %, 45.5 %, and 35.7 % for contralateral breast D 0.03cc and D mean , respectively (all p < 0.001). Among the 240 patients included, the clinicians preferred the autoplan for 119 patients, with manplans preferred for 96 cases (p = 0.01). Per centre there were on average 5.0 (1SD) patients with a preferred autoplan (range [0-10]), compared to 4.0 +/- 2.7 with a preferred manplan ([0,9]). No differences were observed regarding deliverability. Conclusion: The automation significantly reduced the hands-on planning workload compared to manual ning, while also achieving an overall superiority. However, fine-tuning of the autoplanning configuration clinical implementation may be necessary in some centres to enhance clinicians' satisfaction with the generated autoplans.