Technical Assessment of an Automated Treatment Planning on Dose Escalation of Pancreas Stereotactic Body Radiotherapy

Abstract

Background: Stereotactic body radiotherapy has been suggested to provide high rates of local control for locally advanced pancreatic cancer. However, the close proximity of highly radiosensitive normal tissues usually causes the labor-intensive planning process and may impede further escalation of the prescription dose. Purpose: The present study aims to evaluate the consistency and efficiency of Pinnacle Auto-Planning for pancreas stereotactic body radiotherapy with original prescription and escalated prescription. Methods: Twenty-four patients with pancreatic cancer treated with stereotactic body radiotherapy were studied retrospectively. The prescription is 40 Gy over 5 consecutive fractions. Most of patients (n = 21) also had 3 other different dose-level targets (6 Gy/fraction, 5 Gy/fraction, and 4 Gy/fraction). Two types of plans were generated by Pinnacle Auto-Planning with the original prescription (8 Gy/fraction, 6 Gy/fraction, 5 Gy/fraction, and 4 Gy/fraction) and escalated prescription (9 Gy/fraction, 7 Gy/fraction, 6 Gy/fraction, and 5 Gy/fraction), respectively. The same Auto-Planning template, including beam geometry, intensity-modulated radiotherapy objectives and intensity-modulated radiotherapy optimization parameters, were utilized for all the auto-plans in each prescription group. The intensity-modulated radiotherapy objectives do not include any manually created structures. Dosimetric parameters including percentage volume of PTV receiving 100% of the prescription dose, percentage volume of PTV receiving 93% of the prescription dose, and consistency of the dose-volume histograms of the target volumes were assessed. Dmax and D1 cc of highly radiosensitive organs were also evaluated. Results: For all the pancreas stereotactic body radiotherapy plans with the original or escalated prescriptions, auto-plans met institutional dose constraints for critical organs, such as the duodenum, small intestine, and stomach. Furthermore, auto-plans resulted in acceptable planning target volume coverage for all targets with different prescription levels. All the plans were generated in a one-attempt manner, and very little human intervention is necessary to achieve such plan quality. Conclusions: Pinnacle3 Auto-Planning consistently and efficiently generate acceptable treatment plans for multitarget pancreas stereotactic body radiotherapy with or without dose escalation and may play a more important role in treatment planning in the future.

Automated treatment planning as a dose escalation strategy for stereotactic radiation therapy in pancreatic cancer

“…31 A recent paper addressed the feasibility of automated planning for pancreas SBRT using step-andshoot IMRT technique. 32 The authors reported that, also in this complex anatomical site, all plans met institutional dose constraints for OARs resulting in acceptable planning target volume coverage for all targets with different prescription levels. Based on the aforementioned studies, we applied the Pinnacle Autoplanning engine to the challenging planning optimization of SBRT treatments using SIB strategy for pancreatic cancer.…”

“…In particular, in our clinic, we demonstrated that the implementation of Autoplanning for complex cancer cases planned with SIB strategy as head‐neck and high‐risk prostate cancers translated into a significant increase in dose conformity and reduction in integral dose 31 . A recent paper addressed the feasibility of automated planning for pancreas SBRT using step‐and‐shoot IMRT technique 32 . The authors reported that, also in this complex anatomical site, all plans met institutional dose constraints for OARs resulting in acceptable planning target volume coverage for all targets with different prescription levels.…”

Radiotherapy Treatment Planning in the Age of AI: Are We Ready Yet?

“…With such automation, human planners can be spared from many manual processes and therefore afforded more time to focus on further improving the plan quality. Wang et al ’s study 2 shows such an example in which a commercial ARIR algorithm, Pinnacle AutoPlan, was used to explore the dose-escalation limit of pancreatic stereotactic body radiotherapy (SBRT). Stereotactic body radiotherapy is an important treatment modality for borderline resectable and locally advanced pancreatic cancer that has shown promise but can be limited by normal tissue toxicity.…”