Multi-criteria optimization achieves superior normal tissue sparing in intensity-modulated radiation therapy for oropharyngeal cancer patients.

OBJECTIVES

To evaluate the benefit of intensity-modulated radiation therapy (IMRT) with multi-criteria optimization (MCO) in patients with oropharyngeal cancer (OPC) and compare the dose difference between the MCO plans navigated by physicians and dosimetrists.

MATERIALS AND METHODS

The conventional IMRT plans (nonMCO) and MCO IMRT plans navigated by physicians and dosimetrists (MCOp and MCOd) were created for 30patients with OPC. All the plans were reviewed, and the planning time and dose-volume parameters were compared.

RESULTS

The difference of D among three kinds of plans was not significant (p > 0.05). The maximum dose and D of spinal cord, brain stem, the mean dose of bilateral parotids, cochlea, oral cavity and glottic larynx were lower in MCO plans than those in nonMCO plans (p < 0.017). Furthermore, MCOp showed better bilateral parotids, oral cavity and glottic larynx sparing compared to MCOd (p < 0.017), in which the magnitude was related to the overlapping volume of the corresponding organ at risk (OAR) and targets. The active planning time was reduced by a median of 94.3 min (MCOd vs. nonMCO) or 91.6 min (MCOp vs. nonMCO).

CONCLUSION

MCO IMRT plans significantly reduced the dose of OARs and the active planning time, without compromising the target coverage in OPC patients; navigations by physicians could be beneficial to the dose sparing of the OARs with high complication rate and those overlapping with targets; the constraints could be the predominant factor affecting the results of optimization in the MCO IMRT planning.