MITHRA – multiparametric MR/CT image adapted brachytherapy (MR/CT-IABT) in anal canal cancer: a feasibility study

Abstract

PurposeThe aim of this study is to test a novel multiparametric imaging guided procedure for high-dose-rate brachytherapy in anal canal cancer, in order to evaluate the feasibility and safety.Material and methodsFor this analysis, we considered all consecutive patients who underwent magnetic resonance/computed tomography image adapted brachytherapy (MR/CT-IABT) treated from February 2012 to July 2014. To conduct this project, we formed a working group that established the procedure and identified the indicators and benchmarks to evaluate the feasibility and safety. We considered the procedure acceptable if 90% of the indicators were consistent with the benchmarks. Magnetic resonance imaging with contrast and diffusion weighted imaging were performed with an MRI-compatible dummy applicator in the anus to define the position of the clinical target volume disease and biological information. A pre-implantation treatment planning was created in order to get information on the optimal position of the needles. Afterwards, the patient underwent a simulation CT and the definite post-implantation treatment planning was created.ResultsWe treated 11 patients (4 men and 7 women) with MR/CT-IABT and we performed a total of 13 procedures. The analysis of indicators for procedure evaluation showed that all indicators were in agreement with the benchmark. The dosimetric analysis resulted in a median of V200, V150, V100, V90, V85, respectively of 24.6%, 53.4%, 93.5%, 97.6%, and 98.7%. The median coverage index (CI) was 0.94, the median dose homogeneity index (DHI) was 0.43, the median dose non-uniformity ratio (DNR) resulted 0.56, the median overdose volume index (ODI) was 0.27. We observed no episodes of common severe acute toxicities.ConclusionsBrachytherapy is a possible option in anal cancer radiotherapy to perform the boost to complete external beam radiotherapy (EBRT). Magnetic resonance can also have biological advantages compared to the US. Our results suggest that the multiparametric MR/CT-IABT for anal cancer is feasible and safe. This new approach paves the way to prospective comparison studies between MRI and ultrasound-guided brachytherapy (USBT) in anal canal cancer.

Interventional Oncology: Should Interventional Radiotherapy (Brachytherapy) be Integrated into Modern Treatment Procedures?

“…The knowledge of a proctologist/gynecologist is necessary for optimal orientation and performance of the implantation technique, as well as the presence of an anesthetist at the implantation procedure is obligatory. [22][23][24] In breast cancer IRT, independently from the fact of a planned partial breast or boost implantation, multidisciplinary decision-making is obligatory. The cooperation of imaging experts, pathologists, breast surgeons and IRT/EBRT experts offers the best possible treatment results.…”

Late gastrointestinal toxicity after radiotherapy for anal cancer: a systematic literature review

“…Studies reporting the long-term outcome of IMRT reported either no or very rare incidence of Grade 3 or higher late sequelae [14,58,61,97,98,[129][130][131]. Three studies found only the gross tumor volume (GTV) dose to be predictive of acute Grade 2 GI toxicity [132][133][134].…”

Can brachytherapy be properly considered in the clinical practice? Trilogy project: The vision of the AIRO (Italian Association of Radiotherapy and Clinical Oncology) Interventional Radiotherapy study group

“…In particular, there is evidence, which has proven that in selected cancers, such as cervical and prostate cancer, BT boost vs. no boost increases overall survival after external beam radiation therapy [8,9,10]. Moreover, there is evidence that the use of intensity modulated or stereotactic radiation therapy as alternatives to BT boost resulted in worse results not only in terms of overall survival, but also with regards to aesthetic results, and function and organ preservation [11,12,13,14].…”