Evaluation of a hybrid automatic planning solution for rectal cancer

BACKGROUND: Script-based planning and knowledge-based planning are two kinds of automatic planning solutions. Hybrid automatic planning may integrate the advantages of both solutions and provide a more robust automatic planning solution in the clinic. In this study, we evaluated and compared a commercially available hybrid planning solution with manual planning and script-based planning. METHODS: In total, 51 rectal cancer patients in our institution were enrolled in this study. Each patient generated 7 plans: one clinically accepted manual plan ([Formula: see text] ), three script-based plans and three hybrid plans generated with the volumetric-modulated arc therapy technique and 3 different clinical goal settings: easy, moderate and hard ([Formula: see text] , [Formula: see text] , [Formula: see text] , [Formula: see text] , [Formula: see text] and [Formula: see text] ). Planning goals included planning target volume (PTV) D(max), bladder D(mean) and femur head D(mean). The PTV prescription was the same (50.00 Gy) for the 3 goal settings. The hard setting required a lower PTV D(max) and stricter organ at risk (OAR) dose, while the easy setting was the opposite. Plans were compared using dose metrics and plan quality metric (PQM) scores, including bladder D(15) and D(50), left and right femur head D(25) and D(40), PTV D(2), D(98), CI (conformity index) and HI (homogeneity index). RESULTS: Compared to manual planning, hybrid planning with all settings significantly reduced the OAR dose (p < 0.05, paired t-test or Wilcoxon signed rank test) for all dose-volume indices, except D(25) of the left femur head. For script-based planning, [Formula: see text] significantly increased the OAR dose for the femur head and D(2) and the PTV homogeneity index (p < 0.05, paired t-test or Wilcoxon signed rank test). Meanwhile, the maximum dose of the PTV was largely increased with hard script-based planning (D2 = 56.06 ± 7.57 Gy). For all three settings, the comparison of PQM between hybrid planning and script-based planning showed significant differences, except for D(25) of the left femur head and PTV D(2). The total PQM showed that hybrid planning could provide a better and more robust plan quality than script-based planning. CONCLUSIONS: The hybrid planning solution was manual-planning comparable for rectal cancer. Hybrid planning can provide a better and more robust plan quality than script-based planning. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13014-022-02129-9.