Advantages of IMRT optimization with MCO compared to IMRT optimization without MCO in reducing small bowel high dose index for cervical cancer patients-individualized treatment options

Zejun Jiang; Gongsen Zhang; Tao Sun; Guifang Zhang; Xinqiang Zhang; Xiangyue Kong; Yong Yin

doi:10.21037/tcr-22-2792

Advantages of IMRT optimization with MCO compared to IMRT optimization without MCO in reducing small bowel high dose index for cervical cancer patients-individualized treatment options

Transl Cancer Res. 2023 Dec 31;12(12):3255-3265. doi: 10.21037/tcr-22-2792. Epub 2023 Dec 27.

Authors

Zejun Jiang^#¹, Gongsen Zhang^#², Tao Sun¹, Guifang Zhang¹, Xinqiang Zhang¹, Xiangyue Kong¹, Yong Yin¹

Affiliations

¹ Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China.
² Artificial Intelligence Laboratory, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China.

^# Contributed equally.

Abstract

Background: Traditional intensity-modulated radiation therapy (IMRT) planning for cervical cancer is time-consuming and require iterative repeated optimization. In this study, we focused on leveraging multi-criteria optimization (MCO) to reduce the impact of small bowel high-dose indices on other optimization targets, thereby providing a rapid approach to individualized IMRT for cervical cancer patients.

Methods: Our research involved a cohort of 25 cervical cancer patients who underwent IMRT radiotherapy. The patient inclusion criteria were as follows: (I) histopathological confirmation of cervical cancer, (II) underwent IMRT radiation therapy, and (III) a prescribed dose of 180 cGy/28 fractions for the patient. All plans were replanned by an experienced dosimetrist without the MCO (W-IMRT). On the basis of the W-IMRT plan, the individualized IMRT (I-IMRT) plan was generated under the priority trade-off of reducing the D2cc (D2cc is the minimal dose to the 2 cm3 of the small bowel receiving the maximal dose) index of the small bowel using the MCO method, maintaining target coverage and protecting other organs at risk (OARs) as much as possible. Statistical analysis was performed using the Wilcoxon signature rank test.

Results: When the MCO method was applied to the IMRT plan, the high dose index decreased in the overlapping area between the small bowel and the planning treatment volume (PTV) (P<0.001, respectively). The D2cc index of the small bowel decreased to below 5,200 cGy in all I-IMRT plans. On the other hand, in PTV, the I-IMRT plan achieved a better homogeneity index (HI) compared to the W-IMRT plan. Significant dose reductions were also observed in the bladder (D_mean 144.8 cGy and V₄₀ 1.45%) (P<0.001, respectively), rectum (D_mean 43.9 cGy and V₄₀ 2.7%) (P<0.001, respectively) and bilateral femur heads (D_mean 150 cGy) (P<0.001, respectively).

Conclusions: Dosimetric differences suggest that the I-IMRT plan using the MCO method provides better protection of other OARs and equivalently in PTV coverage, while lowering the high-dose index in the small bowel as much as possible for patients with cervical cancer, thus providing a rapid approach to achieving individualized IMRT for cervical cancer patients.

Keywords: Multi-criteria optimization (MCO); cervical cancer; dosimetric comparisons; intensity-modulated radiation therapy (IMRT); small bowel.