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
Comparative Study
. 2011 Feb;84(998):173-8.
doi: 10.1259/bjr/33089685.

Comparison of conventional and three-dimensional conformal CT planning techniques for preoperative chemoradiotherapy for locally advanced rectal cancer

C Corner  1 , F Khimji, Y Tsang, M Harrison, R Glynne-Jones, R Hughes
Affiliations
Comparative Study

Comparison of conventional and three-dimensional conformal CT planning techniques for preoperative chemoradiotherapy for locally advanced rectal cancer

C Corner et al. Br J Radiol. 2011 Feb.

Abstract

Objectives: We assessed the impact of three-dimensional (3D) conformal planning vs conventional planning of preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC) on small bowel and bladder sparing and in optimising coverage of tumour target volume.

Methods: Conformal and conventional plans were created for 50 consecutive patients. The conformal plan delineated a gross tumour volume (GTV), a clinical target volume (CTV) 1 to cover potential subclinical disease spread, a CTV2 to outline the mesorectum and lymph node areas at risk, and a planning target volume (PTV) to cover set-up error and organ movement. The conventional plan was created using digitally reconstructed radiographs (DRRs). Patients were treated with a dose of 45 Gy in 25 fractions with concurrent chemotherapy over 5 weeks. Dose-volume histograms (DVHs) were created and compared for GTV, PTV, small bowel and bladder. The GTV was covered by the conventional plan in all patients.

Results: Significant differences were shown for median PTV coverage with conformal planning compared with conventional planning: 99.2% vs 94.2% (range 95.9-100% vs 75.5-100%); p<0.05. The median volume of irradiated small bowel was significantly lower for CT plans at all DVH levels. Median bladder doses did not differ significantly.

Conclusion: 3D conformal CT planning is superior to conventional planning in terms of coverage of the tumour volume. It significantly reduces the volume of small bowel irradiated with no decrease in the rate of R0 resection compared with published data, and at the present time should be considered as the standard of care for rectal cancer planning.

PubMed Disclaimer

Figures

Figure 1
Figure 1
A digitally reconstructed radiograph (DRR) showing conventionally applied field borders missing the CT-defined planning target volume (PTV) anteriorly. Anterior border shown by white arrow.
Figure 2
Figure 2
(a) Digitally reconstructed radiograph (DRR) of a three-dimensional conformal CT plan covering the planning target volume (PTV) (black arrow) and using multileaf collimation; gross tumour volume (white arrow). (b) DRR showing conventionally applied field borders missing the CT defined PTV inferiorly (black arrow).
Figure 3
Figure 3
A digitally reconstructed radiograph (DRR) showing conventionally applied field borders more generous superiorly than required from the CT-defined volume to cover the planning target volume (PTV) (black arrow). White arrow shows small bowel in treatment field owing to generous superior border.
See this image and copyright information in PMC

References

    1. The MercuryStudyGroup Diagnostic accuracy of preoperative magnetic resonance imaging in predicting curative resection of rectal cancer: prospective observation study. BMJ 2006;333:779. - PMC - PubMed
    1. Bosset J, Collette L, Calais G, Mineur L, Maingon P, Radosevic-Jelic L, et al. EORTC Radiotherapy Group Trial 22921. Chemotherapy with preoperative radiotherapy in rectal cancer. N Engl J Med 2007;355:1114–23 - PubMed
    1. Gunderson LL, Sosin H. Areas of failure found at reoperation (second or symptomatic look) following curative surgery of adenocarcinoma of the rectum. Clinicopathological correlation and implications for adjuvant therapy. Cancer 1974;34:1278–92 - PubMed
    1. Sebag-Montefiore D, Stephens R, Steele R, Monson J, Grieve R, Khanna S, et al. Preoperative radiotherapy vs selective post-operative chemoradiotherapy in patients with rectal cancer (MRC CR07 and NCIC-CTG C016): a multicentre randomised trial. Lancet 2009;373:811–20 - PMC - PubMed
    1. Gerard JP, Conroy T, Bonnetain F, Bouche O, Chapet O, Closon-Dejardin MT, et al. Preoperative Radiotherapy with or without concurrent fluorouracil and leucovorin in T3-4 rectal cancers: Results of FFCD 9203. J Clin Oncol 2006;24:4620–5 - PubMed

Publication types

MeSH terms