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Feasibility Assessment of Physical Factors of Rectal Cancer Short-Course Chemoradiotherapy with Delayed Surgery
Prog. Med. Phys. 2018;29(4):143-149
Published online December 31, 2018
© 2018 Korean Society of Medical Physics.

Jihye Koo*, Mijoo Chung, Weon Kuu Chung, Sunsik Jin, Dong Wook Kim

*Department of Physics, University of South Florida, Tampa, FL, USA, Department of Radiation Oncology, Kyung Hee University Hospital at Gangdong, Seoul, Korea
Correspondence to: Dong Wook Kim (joocheck@gmail.com)
Tel: 82-2-440-7398  Fax: 82-2-440-7393
Received November 21, 2018; Revised December 18, 2018; Accepted December 18, 2018.
This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
To verify the correlations between the clinical outcomes and physical factors of short-course chemoradiotherapy (SCRT) and long-course chemoradiotherapy (LCRT) with delayed surgery in patients with rectal cancer. Seventy-two patients with rectal cancer were enrolled in this study. Nineteen patients were treated with SCRT (25 Gy, 5 fractions) by intensity-modulated radiation therapy (IMRT), and 53 patients were treated with LCRT (50.4 Gy, 28 fractions) by three-dimensional conformal radiation therapy (3DCRT). Various physical factors for the target and organs at risk (OARs) were calculated to compare the clinical outcomes. The organ equivalent dose (OED) and lifetime attributable risk (LAR) of bowels and bladders were similar between the SCRT and LCRT groups, whereas the values of femurs were higher in the LCRT group. The equivalent uniform dose and normal tissue complication probability were higher in the LCRT than the SCRT group for most organs. Treatment complications, including anastomotic leakage, bowel adhesion, and hematologic toxicity, were not significantly different between SCRT and LCRT groups. CIs were 0.84±0.2 and 0.61±0.1 for SCRT and LCRT, respectively. The CVIs were 1.07±0.0 and 1.10±0.1, and the HIs were 0.09±0.0 and 0.11±0.1 for SCRT and LCRT, respectively. The sphincter-saving rates were 89.5% and 94.3% for SCRT and LCRT, respectively. The complete pathologic remission rates were 21.1% and 13.2%, and the down-staging rates were 47.4% and 26.4% for SCRT and LCRT, respectively. SCRT with IMRT is comparable to conventional LCRT in both physical indexes and clinical outcome. The preoperative SCRT, compensated by IMRT, is an effective and safe modality.
Keywords : Chemoradiotherapy, Preoperative treatment, Rectal cancer, Physical Index, Short course


December 2018, 29 (4)