History
Contact radiotherapy for treatment of patients with low-lying rectal cancer was introduced at McGill University in 1987 with the use of a 50 kVp orthovoltage x-ray unit (Siemens, Dermopan). Irradiation of rectal cancer with low energy photon beams was previously established in France by Jean Papillon during the 1970s.
In 1997, we started the treatment of locally advanced rectal cancer using MR imaging for tumor localization and Conformal Preoperative Endorectal Brachytherapy for delivery of radiation dose.
Initially, we were using a balloon-like endorectal applicator called Novi Sad, made by Nucletron, a Dutch company that was considered a reference manufacturer of brachytherapy equipment. This treatment modality is based on a High Dose Rate Brachytherapy afterloader, which employs an Iridium-192 (Ir-192) radioactive source. The concept was to deliver highly conformal escalated dose to rectal tumors. At that time, we used CT images for positioning purpose while the dosimetry dose distribution calculations were carried out with an in-house-developed treatment planning software.
In 2002, our group published the first promising results of using brachytherapy in treatment of rectal cancer but the publication was initially received with skepticism by both surgeons and radiation oncologists. However, 10 years later, the group leader (Dr. Té Vuong) published a review paper with a group of world-leading colorectal surgeons, which allayed the initial skepticism and the technique was officially recognized as a viable option for treatment of certain rectal tumors.
In the year 2000, the Nucletron introduced the very first commercially available treatment planning software (Plato), which marked the opening of a new era in brachytherapy: the era of Image Guided Brachytherapy (IGBT). From the very beginning, we embraced this new technology for the brachytherapy treatment planning of patients with locally advanced rectal cancer.
In 2005, as a result of a collaborative effort with Nucletron, a new applicator was designed (Intracavitary Mold Applicator) allowing for improved conformal dose delivery with 8 channels equally distributed and a central shielding rod. This highly conformal dose delivery allowed us to further expand the clinical application to include inoperable rectal cancer patients treated with EMIA Radiation therapy as a boost modality after external beam treatment.
In 2010 we acquired a Xoft 50 kVp x-ray treatment unit that is capable of mimicking the Papillon technique by the use of a rigid rectoscope. Over the years and based on acquired clinical experience, we were working on further developments for both 50 kVp as well as High Dose Rate brachytherapy applicators.
Currently, in collaboration with Xoft, we are working on novel applicator designs that will not only improve the patient comfort and dose conformity but will also allow for an imaging option during the treatment delivery. In a similar effort, we are exploring the possibility for building tungsten shielding collimator-based Intensity Modulated Brachytherapy (IMBT) which, as we have already shown, will provide an even better dose conformity. These improvements will lead toward a new way of treating rectal cancer by means of the EMIA Radiation Therapy.
