Bridging the Gap of Radiotherapy Treatment Planning Quality between High-Income, and Low- and Middle-Income Countries Using Knowledge-Based Planning

Abstract

<h3>Purpose/Objective(s)</h3> Radiotherapy departments in low- and middle-income countries (LMICs) have started introducing intensity-modulated radiotherapy (IMRT). IMRT has become the standard of care in high-income countries (HIC) due to reduced toxicity and improved outcomes in a wide variety of cancers. The purpose of this work is to demonstrate the feasibility of adapting knowledge-based planning (KBP) models established in a HIC to a LMIC lacking experience in IMRT to improve plan quality and planning efficiency. <h3>Materials/Methods</h3> A new o-ring linear accelerator was installed at a hospital in Guatemala in 2019 and has been used to treat ∼80 patients daily with IMRT. Two KBP models developed on a cohort of prostate cancer patients at a university in the US were applied in the hospital in Guatemala to create 12 IMRT plans for 7 prostate patients with different prescriptions, including simultaneous-integrated and sequential boosts). Plan quality described by dose-volume histograms (DVH) metrics and planning time were compared between the plans created with the KBP models and those created manually by local dosimetrists or physicists. <h3>Results</h3> The plans created using these KBP models achieved similar or better coverage over the planning target volume in each plan, and showed a lower dose to bladder and rectum in 11 of 12 plans, and the remainder showed a comparable dose distribution and DVH for rectum and bladder. Sum plans showed better rectal sparing for all patients with V50Gy reduced between 1%-30.4% and bladder sparing for 6 of 7 patients with V50Gy reduced between 1.3% -16.8%. The time efficiency to create IMRT plans using KBP models improved three-fold, on average one hour versus three hours, respectively. <h3>Conclusion</h3> Despite different prescriptions, guidelines and demographics of cancer patients between two institutions in a HIC and LMIC, this work demonstrates that KBP can be a useful tool in ensuring consistent, high-quality IMRT plans at institutions with little to no experience in inverse planning. In addition, KBP has the potential to improve capacity with higher efficiency and may help address the shortage of medical physicists and dosimetrists in LMICs.