Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Nov;21(11):141-152.
doi: 10.1002/acm2.13049. Epub 2020 Oct 15.

Beam angle comparison for distal esophageal carcinoma patients treated with intensity-modulated proton therapy

Hongying Feng  1 , Terence T Sio  1 , William G Rule  1 , Ronik S Bhangoo  1 , Pedro Lara  1 , Christopher L Patrick  1 , Shawn Korte  1 , Mirek Fatyga  1 , William W Wong  1 , Steven E Schild  1 , Jonathan B Ashman  1 , Wei Liu  1
Affiliations

Beam angle comparison for distal esophageal carcinoma patients treated with intensity-modulated proton therapy

Hongying Feng et al. J Appl Clin Med Phys. 2020 Nov.

Abstract

Purpose: To compare the dosimetric performances of intensity-modulated proton therapy (IMPT) plans generated with two different beam angle configurations (the Right-Left oblique posterior beams and the Superior-Inferior oblique posterior beams) for the treatment of distal esophageal carcinoma in the presence of uncertainties and interplay effect.

Methods and materials: Twenty patients' IMPT plans were retrospectively selected, with 10 patients treated with the R-L oblique posterior beams (Group R-L) and the other 10 patients treated with the S-I oblique posterior beams (Group S-I). Patients in both groups were matched by their clinical target volumes (CTVs-high and low dose levels) and respiratory motion amplitudes. Dose-volume-histogram (DVH) indices were used to assess plan quality. DVH bandwidth was calculated to evaluate plan robustness. Interplay effect was quantified using four-dimensional (4D) dynamic dose calculation with random respiratory starting phase of each fraction. Normal tissue complication probability (NTCP) for heart, liver, and lung was calculated, respectively, to estimate the clinical outcomes. Wilcoxon signed-rank test was used for statistical comparison between the two groups.

Results: Compared with plans in Group R-L, plans in Group S-I resulted in significantly lower liver Dmean and lung V30Gy[RBE] with slightly higher but clinically acceptable spinal cord Dmax . Similar plan robustness was observed between the two groups. When interplay effect was considered, plans in Group S-I performed statistically better for heart Dmean and V30Gy[RBE] , lung Dmean and V5Gy[RBE] , and liver Dmean , with slightly increased but clinically acceptable spinal cord Dmax . NTCP for liver was significantly better in Group S-I.

Conclusions: IMPT plans in Group S-I have better sparing of liver, heart, and lungs at the slight cost of spinal cord maximum dose protection, and are more interplay-effect resilient compared to IMPT plans in Group R-L. Our study supports the routine use of the S-I oblique posterior beams for the treatments of distal esophageal carcinoma.

Keywords: beam angle; esophageal cancer; intensity-modulated proton therapy; interplay effect.

PubMed Disclaimer

Conflict of interest statement

Terence T. Sio, MD, MS, provides strategic and scientific recommendations as a member of the Advisory Board and speaker for Novocure, Inc. This position has no relation to this manuscript. All other authors have no additional conflict to disclose.

Figures

Fig. 1
Fig. 1
Two different beam angle configurations. The purple arrows indicate different beam directions. (a) Sagittal plane of a typical patient treated with Superior–Inferior (S‐I) oblique posterior beams, and (b) transverse plane of a typical patient treated with Right–Left (R‐L) oblique posterior beams.
Fig. 2
Fig. 2
Comparison of the dose‐volume‐histogram indices between plans of Group S‐I and Group R‐L on averaged 4D‐CT. (a) Normalized CTVhigh D95% and CTVhigh D2cc, (b) spinal cord Dmax, (c) stomach V45Gy[RBE]cc, (d) heart Dmean, liver Dmean, and lung Dmean, (e) normalized CTVlow D5%‐D95% and CTVhigh D5%‐D95%, and (f) normalized volume of kidney V18Gy[RBE], liver V30Gy[RBE], lung V5Gy[RBE], lung V20Gy[RBE], heart V30Gy[RBE], and heart V40Gy[RBE]. Boxes in khaki are the results from Group R‐L, while blue boxes are the results from Group S‐I. Numbers on the top are P‐values from Wilcoxon signed‐rank test. P‐values that indicate statistical significance (<0.05) are in red and italicized.
Fig. 3
Fig. 3
Comparison of the dose‐volume‐histogram indices between plans of Group S‐I and Group R‐L on the maximum inhalation phase. (a) Normalized CTVhigh D95% and CTVhigh D2cc, (b) spinal cord Dmax, (c) stomach V45Gy[RBE]cc, (d) heart Dmean, liver Dmean, and lung Dmean, (e) normalized CTVlow D5%‐D95% and CTVhigh D5%‐D95%, and (f) normalized volume of kidney V18Gy[RBE], liver V30Gy[RBE], lung V5Gy[RBE], lung V20Gy[RBE], heart V30Gy[RBE], and heart V40Gy[RBE]. Boxes in khaki are the results from Group R‐L, while blue boxes are the results from Group S‐I. Numbers on the top are P‐values from Wilcoxon signed‐rank test. P‐values that indicate statistical significance (<0.05) are in red and italicized.
Fig. 4
Fig. 4
Comparison of the dose‐volume‐histogram indices between plans of Group S‐I and Group R‐L on the maximum exhalation phase. (a) Normalized CTVhigh D95% and CTVhigh D2cc, (b) spinal cord Dmax, (c) stomach V45Gy[RBE]cc, (d) heart Dmean, liver Dmean, and lung Dmean, (e) normalized CTVlow D5%‐D95% and CTVhigh D5%‐D95%, and (f) normalized volume of kidney V18Gy[RBE], liver V30Gy[RBE], lung V5Gy[RBE], lung V20Gy[RBE], heart V30Gy[RBE], and heart V40Gy[RBE]. Boxes in khaki are the results from Group R‐L, while blue boxes are the results from Group S‐I. Numbers on the top are P‐values from Wilcoxon signed‐rank test. P‐values that indicate statistical significance (<0.05) are in red and italicized.
Fig. 5
Fig. 5
Comparison of the dose‐volume‐histogram bandwidths between plans of Group S‐I and Group R‐L on the averaged 4D‐CT. (a) Normalized CTVhigh D95% and CTVhigh D2cc, (b) spinal cord Dmax, (c) stomach V45Gy[RBE]cc, (d) heart Dmean, liver Dmean, and lung Dmean, (e) normalized CTVlow D5%‐D95% and CTVhigh D5%‐D95%, and (f) normalized volume of kidney V18Gy[RBE], liver V30Gy[RBE], lung V5Gy[RBE], lung V20Gy[RBE], heart V30Gy[RBE], and heart V40Gy[RBE]. Boxes in khaki are the results from Group R‐L, while blue boxes are the results from Group S‐I. Numbers on the top are P‐values from Wilcoxon signed‐rank test. P‐values that indicate statistical significance (<0.05) are in red and italicized.
Fig. 6
Fig. 6
Comparison of the dose‐volume‐histogram bandwidths between plans of Group S‐I and Group R‐L on the maximum inhalation phase. (a) Normalized CTVhigh D95% and CTVhigh D2cc, (b) spinal cord Dmax, (c) stomach V45Gy[RBE]cc, (d) heart Dmean, liver Dmean, and lung Dmean, (e) normalized CTVlow D5%‐D95% and CTVhigh D5%‐D95%, and (f) normalized volume of kidney V18Gy[RBE], liver V30Gy[RBE], lung V5Gy[RBE], lung V20Gy[RBE], heart V30Gy[RBE], and heart V40Gy[RBE]. Boxes in khaki are the results from Group R‐L, while blue boxes are the results from Group S‐I. Numbers on the top are P‐values from Wilcoxon signed‐rank test. P‐values that indicate statistical significance (<0.05) are in red and italicized.
Fig. 7
Fig. 7
Comparison of the dose‐volume‐histogram bandwidths between plans of Group S‐I and Group R‐L on the maximum exhalation phase. (a) Normalized CTVhigh D95% and CTVhigh D2cc, (b) spinal cord Dmax, (c) stomach V45Gy[RBE]cc, (d) heart Dmean, liver Dmean, and lung Dmean, (e) normalized CTVlow D5%‐D95% and CTVhigh D5%‐D95%, and (f) normalized volume of kidney V18Gy[RBE], liver V30Gy[RBE], lung V5Gy[RBE], lung V20Gy[RBE], heart V30Gy[RBE], and heart V40Gy[RBE]. Boxes in khaki are the results from Group R‐L, while blue boxes are the results from Group S‐I. Numbers on the top are P‐values from Wilcoxon signed‐rank test. P‐values that indicate statistical significance (<0.05) are in red and italicized.
Fig. 8
Fig. 8
Comparison of the dose‐volume‐histogram indices between plans of Group S‐I and Group R‐L with interplay effect considered. (a) Normalized CTVhigh D95% and CTVhigh D2cc, (b) spinal cord Dmax, (c) stomach V45Gy[RBE]cc, (d) heart Dmean, liver Dmean, and lung Dmean, (e) normalized CTVlow D5%‐D95% and CTVhigh D5%‐D95%, and (f) normalized volume of kidney V18Gy[RBE], liver V30Gy[RBE], lung V5Gy[RBE], lung V20Gy[RBE], heart V30Gy[RBE], and heart V40Gy[RBE]. Boxes in khaki are the results from Group R‐L, while blue boxes are the results from Group S‐I. Numbers on the top are P‐values from Wilcoxon signed‐rank test. P‐values that indicate statistical significance (<0.05) are in red and italicized.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA: Cancer J Clin. 2018;68:394–424. - PubMed
    1. Siegel RL, Miller KD, Jemal A. Cancer statistics, 2020. CA: Cancer J Clin. 2020;70:7–30. - PubMed
    1. Kole TP, Aghayere O, Kwah J, Yorke ED, Goodman KA. Comparison of heart and coronary artery doses associated with intensity‐modulated radiotherapy versus three‐dimensional conformal radiotherapy for distal esophageal cancer. Int J Radiat Oncol Biol Phys. 2012;83:1580–1586. - PubMed
    1. Gharzai L, Verma V, Denniston KA, Bhirud AR, Bennion NR, Lin C. Radiation therapy and cardiac death in long‐term survivors of esophageal cancer: an analysis of the surveillance, epidemiology, and end result database. PLoS One. 2016;11:e0158916. - PMC - PubMed
    1. Water TA, Bijl HP, Schilstra C, Pijls‐Johannesma M, Langendijk JA. The potential benefit of radiotherapy with protons in head and neck cancer with respect to normal tissue sparing: a systematic review of literature. Oncologist. 2011;16:366–377. - PMC - PubMed