Brachytherapy Applicator Developed for Endometrial Cancer Patients Allows for More Precise Radiation Dose

The Capri applicator, devised to increase patient comfort and allow clinicians to better sculpt the radiotherapy dose, was presented in April 2011 at the annual American Brachytherapy Society (ABS) meeting in San Diego, CA, USA. The applicator can also be used for treatment of vaginal and rectal cancers.

Designed with the intention of improving patient comfort, it is a lightweight balloon applicator that is inflated upon insertion to adapt to each patient's anatomy and hold it in place during treatment. Prior to the Capri applicator's development, the principle brachytherapy option for endometrial cancer patients involved inserting rigid cylinders, which may require the fixation of the applicator to the treatment table. The Capri applicator is also compatible with computed tomography (CT) imaging, which enables doctors to use it with three-dimensional (3D) imaging to plan their treatments and determine exactly where they want to deposit the dose. The device was manufactured by Varian Medical Systems, Inc. (Palo Alto, CA, USA).

"We believe this applicator is a breakthrough for gynecological treatments and will make a huge difference in treating post-hysterectomy endometrial cancer patients," said Ted Jackson, PhD, Varian BrachyTherapy's director of product development and engineering. "Our design is aimed at enhancing patient comfort and improving ease of use and we believe it has the potential to reduce the radiation dose to surrounding healthy tissues."

The Capri applicator has US Food and Drug Administration (FDA) clearance for gynecologic and rectal treatments in the United States and is awaiting CE approval for sale in Europe.

Dr. Rakesh Patel, the medical director of the Targeted Radiation Institute at Western Radiation Oncology (WRO; Mountain View, CA, USA), said that the Capri applicator supports 3D treatment planning capabilities for high-dose rate (HDR) vaginal brachytherapy. "We expect that the result will be to significantly improve dose distribution by allowing us to reduce the exposure of the rectum and bladder," he said. "This feature combined with its design aimed at improving ease of use and patient comfort enhances the current methods for this type of treatment. From our clinical observations, the patients tolerate the treatment very well."

Brachytherapy involves treating cancer by temporarily placing radioactive sources within or adjacent to tumors. About half of all US endometrial cancer patients receive brachytherapy as the standard of care post-hysterectomy. Endometrial cancer is the most common gynecologic cancer and the majority of women require a hysterectomy as part of their treatment.

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