Dose planning objectives in anal canal cancer <scp>IMRT</scp>: the <scp>TROG ANROTAT</scp> experience

Brown, Elizabeth; Cray, Alison; Haworth, Annette; Chander, Sarat; Lin, Robert; Subramanian, Brindha; Ng, Michael

doi:10.1002/jmrs.99

Cited by 5 publications

(1 citation statement)

References 24 publications

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“…For the development and implementation of evidenced based OAR dose constraints, consistent contouring is imperative [ 25 , 26 ]. This is particularly true in AC IMRT where the proximity of OAR and tumour volumes often requires a compromise between adequate coverage and safety.…”

Section: Discussionmentioning

confidence: 99%

The impact of contour variation on tumour control probability in anal cancer

et al. 2018

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BackgroundWhile intensity modulated radiotherapy (IMRT) has been widely adopted for the treatment of anal cancer (AC), the added contour complexity poses potential risks. This study investigates the impact of contour variation on tumour control probability (TCP) when using IMRT for AC.MethodsNine Australian centres contoured a single computed tomography dataset of a patient with AC. The same optimised template-based IMRT planning protocol was applied to each contour set to generate nine representative treatment plans and their corresponding dose volume histograms. A geometric analysis was performed on all contours. The TCP was calculated for each plan using the linear quadratic and logitEUD model.ResultsThe median concordance index (CI) for the bladder, head and neck of femur, bone marrow, small bowel and external genitalia was 0.94, 0.88, 0.84, 0.65 and 0.65, respectively. The median CI for the involved nodal, primary tumour and elective clinical target volumes were 0.85, 0.77 and 0.71, respectively. Across the nine plans, the TCP was not significantly different. Variation in TCP between plans increased as tumour cell load increased or radiation dose decreased.ConclusionsWhen using IMRT for AC, contour variations generated from a common protocol within the limits of minor deviations do not appear to have a significant impact on TCP. Contouring variations may be more critical with increasing tumour cell load or reducing radiotherapy dose.

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Section: Discussionmentioning

confidence: 99%

The impact of contour variation on tumour control probability in anal cancer

et al. 2018

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Dosimetric comparison of helical tomotherapy and VMAT for anal cancer: A single institutional experience

2019

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Adjuvant external beam radiotherapy after therapeutic groin lymphadenectomy for patients with melanoma: a dosimetric comparison of three-dimensional conformal and intensity-modulated radiotherapy techniques

Adams

Foote²,

Brown³

et al. 2017

Melanoma Research

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Radiotherapy after lymph node dissection is recommended in high-risk melanoma cases. The aim of this study is to assess whether intensity-modulated radiotherapy (IMRT) offers advantages over three-dimensional conformal radiotherapy (3DCRT) in the groin nodal basin. Fifteen consecutively treated patients (5 3DCRT and 10 IMRT) were selected. Optimized theoretical plans using the other modality were created - enabling direct comparisons of 3DCRT and IMRT. Target volume and organs at risk constraints were assessed as achieved or as having minor (≤5%) or major (>5%) deviations. The Wilcoxon signed-rank test was used to compare the dose received from each patient plan (3DCRT vs. IMRT), whereas the Mann-Whitney U-test was used to compare clinical plans with theoretical plans. Fisher's exact test was used to compare categorical data. Target coverage was achievable in most patients (major deviations - 1 IMRT and 3 3DCRT). Conformity index improved with IMRT - median 0.65, range 0.48-0.81, versus median 0.44, range 0.29-0.60 for 3DCRT; P value less than 0.001. All 3DCRT plans had major deviations for femoral head/neck constraints. Twelve and 13 IMRT plans achieved the high (V42<5%) and low (V36<35%) constraints; P value less than 0.001. IMRT delivered statistically significant lower doses to small bowel volumes up to 40 ml. There were no differences in beam numbers used nor dosimetric endpoints measured when clinical plans were compared with theoretical plans. IMRT appears to allow superior conformity of dose to the target volume while relatively sparing the adjacent the bowel and femoral head/neck. This may reduce toxicity while maintaining control rates.

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Dose planning objectives in anal canal cancer IMRT: the TROG ANROTAT experience

Cited by 5 publications

References 24 publications

The impact of contour variation on tumour control probability in anal cancer

The impact of contour variation on tumour control probability in anal cancer

Dosimetric comparison of helical tomotherapy and VMAT for anal cancer: A single institutional experience

Adjuvant external beam radiotherapy after therapeutic groin lymphadenectomy for patients with melanoma: a dosimetric comparison of three-dimensional conformal and intensity-modulated radiotherapy techniques

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