To compare target volume delineation of anal cancer using positron emission tomography (PET) and magnetic resonance imaging (MRI) with respect to inter-observer and inter-modality variability.
Nineteen patients with anal cancer undergoing chemoradiotherapy were prospectively included. Planning computed tomography (CT) images were co-registered with 18F–fluorodexocyglucose (FDG) PET/CT images and T2 and diffusion weighted (DW) MR images. Three oncologists delineated the Gross Tumor Volume (GTV) according to national guidelines and the visible tumor tissue (GTVT). MRI and PET based delineations were evaluated by absolute volumes and Dice similarity coefficients.
The median volume of the GTVs was 27 and 31 cm3 for PET and MRI, respectively, while it was 6 and 11 cm3 for GTVT. Both GTV and GTVT volumes were highly correlated between delineators (r = 0.90 and r = 0.96, respectively). The median Dice similarity coefficient was 0.75 when comparing the GTVs based on PET/CT (GTVPET) with the GTVs based on MRI and CT (GTVMRI). The median Dice coefficient was 0.56 when comparing the visible tumor volume evaluated by PET (GTVT_PET) with the same volume evaluated by MRI (GTVT_MRI). Margins of 1–2 mm in the axial plane and 7–8 mm in superoinferior direction were required for coverage of the individual observer’s GTVs.
The rather good agreement between PET- and MRI-based GTVs indicates that either modality may be used for standard target delineation of anal cancer. However, larger deviations were found for GTVT, which may impact future tumor boost strategies.
Vuong T, Kopek N, Ducruet T, Portelance L, Faria S, Bahoric B, et al. Conformal therapy improves the therapeutic index of patients with anal canal cancer treated with combined chemotherapy and external beam radiotherapy. Int J Radiat Oncol. 2007;67(5):1394–400. CrossRef
Kachnic LA, Winter K, Myerson RJ, Goodyear MD, Willins J, Esthappan J, et al. RTOG 0529: a phase 2 evaluation of dose-painted intensity modulated radiation therapy in combination with 5-fluorouracil and Mitomycin-C for the reduction of acute morbidity in carcinoma of the Anal Canal. Int J Radiat Oncol. 2013;86(1):27–33. CrossRef
Ng M, Leong T, Chander S, Chu J, Kneebone A, Carroll S, et al. Australasian gastrointestinal trials group (AGITG) contouring atlas and planning guidelines for intensity-modulated radiotherapy in anal cancer. Int J Radiat Oncol. 2012;83(5):1455–62. CrossRef
Benson A, Arnoletti JP, Bekaii-Saab T, Chan E, Chen YJ, Choti MA, et al. Anal carcinoma, version 2.2012 featured updates to the NCCN guidelines. J Natl Compr Canc Ne. 2012;10(4):449–54. CrossRef
Yates A, Carroll S, Kneebone A, Tse R, Horvath L, Byrne C, et al. Implementing intensity-modulated radiotherapy with simultaneous integrated boost for anal cancer: 3 year outcomes at two Sydney institutions. Clin Oncol-Uk. 2015;27(12):700–7. CrossRef
Glynne-Jones R, Renehan A. Current treatment of anal Squamous cell carcinoma. Hematol Oncol Clin N. 2012;26(6):1315–+. CrossRef
Heukelom J, Hamming O, Bartelink H, Hoebers F, Giralt J, Herlestam T, et al. Adaptive and innovative radiation treatment FOR improving cancer treatment outcomE (ARTFORCE); a randomized controlled phase II trial for individualized treatment of head and neck cancer. BMC Cancer. 2013;13:84. CrossRefPubMedPubMedCentral
Glynne-Jones R, Goh V, Agarwal A, Maher H, Dubash S, Hughes R. Anal carcinoma. In: Grosu A, Nieder C, editors. Target volume definition in radiation oncology. Heidelberg: Springer-Verlag; 2015. p. 194–216.
Roels S, Slagmolen P, Nuyts J, Lee JA, Loeckx D, Maes F, et al. Biological image-guided radiotherapy in rectal cancer: challenges and pitfalls. Int J Radiat Oncol. 2009;75(3):782–90. CrossRef
Braendengen M, Hansson K, Radu C, Siegbahn A, Jacobsson H, Glimelius B. Delineation of gross tumor volume (Gtv) for radiation treatment planning of locally advanced rectal cancer using information from Mri or Fdg-pet/ct: a prospective study. Int J Radiat Oncol. 2011;81(4):E439–E45. CrossRef
Shali SM, Schmitt V, Behrendt FF, Winz OH, Heinzel A, Mottaghy FM, et al. Metabolic tumour volume of anal carcinoma on (18)FDG PET/CT before combined radiochemotherapy is the only independant determinant of recurrence free survival. Eur J Radiol. 2016;85(8):1390–4. CrossRef
Patel DA, Chang ST, Goodman KA, Quon A, Thorndyke B, Gambhir SS, et al. Impact of integrated PET/CT on variability of target volume delineation in rectal cancer. Technol Cancer Res T. 2007;6(1):31–6. CrossRef
- Target volume delineation of anal cancer based on magnetic resonance imaging or positron emission tomography
Bernt Louni Rekstad
Taran Paulsen Hellebust
Marianne Grønlie Guren
- BioMed Central
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