Mustafa ÜNSAL, Sedenay OSKEROĞLU KAPLAN, Süleyman ALTIN, Yunus SARALI, Halil AKBÖRÜ

Dosimetric Comparison of Intensity-Modulated Radiotherapy and Volumetric Arc Therapy for Rectal Cancer

OBJECTIVEThe aim of the present study is the dosimetric comparison of intensity-modulated radiation therapy andvolumetric arc therapy (VMAT) that are currently applied in the preoperative radiotherapy of locallyadvanced rectal cancer.METHODSTen patients with locally advanced rectal cancer were recontoured according to defined protocol oncomputed tomography simulation that was previously scanned. Dosimetric comparison was performedfor each patient with 7 and 9 fields intensity-modulated radiation therapy and VMAT. Compared dosimetric parameters were determined as doses of organs at risk, the total duration of treatment, targetcoverage, conformity index, homogeneity index, and the total monitor unit (MU).RESULTSAll plans provided comparable dosimetric parameters for target volumes. Arc plans demonstrated astatistically significant benefit with lower doses on V15 and Dmean of the small bowel than intensity-modulated radiation therapy. Arc plans were obviously superior relating to measured volumes of the wholebody, and plans with 7 field had the worst results. In addition, the reduction in total treatment time byapproximately 60% was achieved in arc plans.CONCLUSIONVMAT with short treatment duration and low MUs can be considered as providing a more comfortableand qualified treatment.

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1. Sauer R, Becker H, Hohenberger W, Rödel C, Wittekind C, Fietkau R, et al.; German Rectal Cancer Study Group. Preoperative versus postoperative chemoradiotherapy for rectal cancer. N Engl J Med 2004;351(17):1731–40.
2. Rödel C, Sauer R. Integration of novel agents into combined-modality treatment for rectal cancer patients. Strahlenther Onkol 2007;183(5):227–35.
3. Frykholm GJ, Glimelius B, Påhlman L. Preoperative or postoperative irradiation in adenocarcinoma of the rectum: final treatment results of a randomized trial and an evaluation of late secondary effects. Dis Colon Rectum 1993;36(6):564–72.
4. Kollmorgen CF, Meagher AP, Wolff BG, Pemberton JH, Martenson JA, Illstrup DM. The long-term effect of adjuvant postoperative chemoradiotherapy for rectal carcinoma on bowel function. Ann Surg 1994;220(5):676–82.
5. Huang EH, Pollack A, Levy L, Starkschall G, Dong L, Rosen I, et al. Late rectal toxicity: dose-volume effects of conformal radiotherapy for prostate cancer. Int J Radiat Oncol Biol Phys 2002;54(5):1314–21. 6. Kupelian PA, Reddy CA, Carlson TP, Willoughby TR. Dose/volume relationship of late rectal bleeding after external beam radiotherapy for localized prostate cancer: absolute or relative rectal volume? Cancer J 2002;8(1):62–6.
7. Tho LM, Glegg M, Paterson J, Yap C, MacLeod A, McCabe M, et al. Acute small bowel toxicity and preoperative chemoradiotherapy for rectal cancer: investigating dose-volume relationships and role for inverse planning. Int J Radiat Oncol Biol Phys 2006;66(2):505–13.
8. Letschert JG, Lebesque JV, de Boer RW, Hart AA, Bartelink H. Dose-volume correlation in radiation-related late small-bowel complications: a clinical study. Radiother Oncol 1990;18(4):307-20.
9. Letschert JG, Lebesque JV, de Boer RW, Hart AA, Bartelink H. Dose-volume correlation in radiation-related late small-bowel complications: a clinical study. Radiother Oncol 1990;18(4):307–20.
10.Baglan KL, Frazier RC, Yan D, Huang RR, Martinez AA, Robertson JM. The dose-volume relationship of acute small bowel toxicity from concurrent 5-FUbased chemotherapy and radiation therapy for rectal cancer. Int J Radiat Oncol Biol Phys 2002;52(1):176– 83.
11.Kopp RW, Duff M, Catalfamo F, Shah D, Rajecki M, Ahmad K. VMAT vs. 7-field-IMRT: assessing the dosimetric parameters of prostate cancer treatment with a 292-patient sample. Med Dosim 2011;36(4):365–72.
12.Lawrie TA, Green JT, Beresford M, Wedlake L, Burden S, Davidson SE, et al. Interventions to reduce acute and late adverse gastrointestinal effects of pelvic radiotherapy for primary pelvic cancers. Cochrane Database Syst Rev 2018;1:CD012529.
13.Myerson RJ, Garofalo MC, El Naqa I, Abrams RA, Apte A, Bosch WR, et al. Elective clinical target volumes for conformal therapy in anorectal cancer: a radiation therapyoncology group consensus panel contouring atlas. Int J Radiat Oncol Biol Phys 2009;74(3):824–30.
14.Guerrero Urbano MT, Henrys AJ, Adams EJ, Norman AR, Bedford JL, Harrington KJ, et al. Intensitymodulated radiotherapy in patients with locally advanced rectal cancer reduces volume of bowel treated to high dose levels. Int J Radiat Oncol Biol Phys 2006;65(3):907–16.
15.Robertson JM, Lockman D, Yan D, Wallace M. The dose-volume relationship of small bowel irradiation and acute grade 3 diarrhea during chemoradiotherapy for rectal cancer. Int J Radiat Oncol Biol Phys 2008;70(2):413–8.
16.Aristu JJ, Arbea L, Rodriguez J, Hernández-Lizoain JL, Sola JJ, Moreno M, et al. Phase I-II trial of concurrent capecitabine and oxaliplatin with preoperative intensity-modulated radiotherapy in patients with locally advanced rectal cancer. Int J Radiat Oncol Biol Phys 2008;71(3):748–55.
17.Arbea L, Martínez-Monge R, Díaz-González JA, Moreno M, Rodríguez J, Hernández JL, et al. Fourweek neoadjuvant intensity-modulated radiation therapy with concurrent capecitabine and oxaliplatin in locally advanced rectal cancer patients: a validation phase II trial. Int J Radiat Oncol Biol Phys 2012;83(2):587–93.
18.Zhu J, Gu W, Lian P, Sheng W, Cai G, Shi D, et al. A phase II trial of neoadjuvant IMRT-based chemoradiotherapy followed by one cycle of capecitabine for stage II/III rectal adenocarcinoma. Radiat Oncol 2013;8:130.
19.Hong TS, Moughan J, Garofalo MC, Bendell J, Berger AC, Oldenburg NB, et al. NRG Oncology Radiation Therapy Oncology Group 0822: A Phase 2 Study of Preoperative Chemoradiation Therapy Using Intensity Modulated Radiation Therapy in Combination With Capecitabine and Oxaliplatin for Patients With Locally Advanced Rectal Cancer. Int J Radiat Oncol Biol Phys 2015;93(1):29–36.
20.Wolff HA, Wagner DM, Conradi LC, Hennies S, Ghadimi M, Hess CF, et al. Irradiation with protons for the individualized treatment of patients with locally advanced rectal cancer: a planning study with clinical implications. Radiother Oncol 2012;102(1):30–7.
21.Stromberger C, Kom Y, Kawgan-Kagan M, Mensing T, Jahn U, Schneider A, et al. Intensity-modulated radiotherapy in patients with cervical cancer. An intra-individual comparison of prone and supine positioning. Radiat Oncol 2010;5:63.
22.Kim JY, Kim DY, Kim TH, Park SY, Lee SB, Shin KH, et al. Intensity-modulated radiotherapy with a belly board for rectal cancer. Int J Colorectal Dis 2007;22(4):373–9.