Hyperpolarized 13C MR Imaging of Lactate in Patients With Locally Advanced Cervical Cancer for Treatment With Definitive Chemoradiation Therapy

Patients with locally advanced cervical cancer can be offered definitive treatment with radiation therapy with concurrent chemotherapy for curative treatment. Brachytherapy is an essential part of this treatment, used to deliver high central doses after external beam radiation. Three-dimensional image-guided brachytherapy (3DIGBT) is gradually becoming the standard of care in many centres across the world. The use of Magnetic Resonance Imaging (MRI) or Computerized Tomography (CT) for planning helps ensure adequate coverage of tumours, minimizing doses to organs at risk. However, standard imaging modalities used in 3DIGBT typically include T2 and T1 weighted MRI sequences or CT scans and visualizing of the disease can often be challenging. Furthermore, it can be difficult to differentiate between active cervical cancer and fibrosis, leading to treatment of larger volumes when there is uncertainty (Akila contouring study).

High tumour lactate concentration has been linked to poor clinical outcomes in patients with solid tumours, including cervical cancers treated with radiation therapy [1, 2]. Three-dimensional imaging of tumour lactate in patients with locally advanced cervical cancers may be useful in identifying regions of radiation resistance and guiding treatment with chemoradiation and brachytherapy. The objective of this study is to image patients with locally advanced cervical cancer using hyperpolarized 13C MR imaging to obtain a measure of lactate levels in cervical tumours. Lactate images and measurements will be correlated with diffusion-weighted MRI, 18FDG-PET imaging and bioluminescence microscopy (BLI).

Up to ten participants with cervical cancer that are to receive radical treatment with radiation and possible concurrent cisplatin will be recruited for this study from Sunnybrook Health Sciences Centre (Sunnybrook). A snap-frozen biopsy of the tumour will be taken at the first clinic visit. Prior to treatment, baseline diffusion weighted MRI images and 18FDG-PET scans will be obtained. Hyperpolarized 13C MR imaging will be performed through the injection of 13C pyruvate and measurements of tumour lactate levels. Lactate levels will be correlated with measurements from bioluminescence microscopy. The images from hyperpolarized 13C MR imaging will also be compared to diffusion-weighted MR and 18FDG-PET images.

The purpose of this study is to image tumour lactate in study participants with locally advanced cervical cancer. Our hypothesis is that lactate content in cervical tumours, as measured by hyperpolarized 13C Magnetic Resonance (MR) imaging, will correlate with diffusion-weighted MRI and 18FDG-PET. Furthermore, lactate imaging will potentially provide additional and more specific information regarding the metabolic activity of cervical tumours, thereby identifying regions of radiation resistance and guiding radiation treatment and brachytherapy.