• Int. J. Radiat. Oncol. Biol. Phys. · Apr 2009

    Randomized Controlled Trial Multicenter Study

    Mathematical model for evaluating incidence of acute rectal toxicity during conventional or hypofractionated radiotherapy courses for prostate cancer.

    • Lidia Strigari, Giorgio Arcangeli, Stefano Arcangeli, and Marcello Benassi.
    • Laboratory of Medical Physics and Expert Systems, Regina Elena Institute, Rome, Italy. strigari@ifo.it
    • Int. J. Radiat. Oncol. Biol. Phys. 2009 Apr 1; 73 (5): 1454-60.

    PurposeTo describe the radiation-induced acute rectal toxicity (ART) using a modified Lyman-Kutcher-Burman normal tissue complication probability model and parameters set, taking into account the overall treatment time.Methods And MaterialsA total of 160 patients underwent three-dimensional conformal radiotherapy to the prostate and seminal vesicles and were randomized to receive 80 Gy in 40 fractions within 8 weeks (Group A) or 62 Gy in 20 fractions within 5 weeks, 4 d/wk (Group B). An additional 52 patients (Group C) underwent intensity-modulated radiotherapy with a hypofractionation schedule consisting of 56 Gy, delivered in 16 fractions (4/wk) of 3.5 Gy. Patients were followed for ART weekly during treatment. The overall treatment time, rectal dose-volume histograms, and ART status, defined as Radiation Therapy Oncology Group Grade 2 or greater gastrointestinal toxicity, were used to determine the modified Lyman-Kutcher-Burman model parameters. The m and n values were obtained from the cohort, and the tolerance doses for 50% complication probability for uniform irradiation [TD(50)(1)(k)] were obtained for each fractionation schedule indicated with k.ResultsOf 212 patients treated with localized prostate radiotherapy, 65 developed Grade for > or = 1 week during treatment. The m and n value was 0.17 and 0.08, respectively. The TD(50)(1)(k) parameter was 79, 62.5, and 53 Gy, respectively for Group A, B, and C.ConclusionThe optimized modified Lyman-Kutcher-Burman normal tissue complication probability model allowed us to describe the ART data from conventional and hypofractionated regimens, using the dose-volume histograms and overall treatment time. This model could prove useful in designing hypofractionation schedules to reduce the incidence of ART.

      Pubmed     Full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…