Functional Imaging in the Assessment of mRCC Response to Sunitinib

Renal cell carcinoma (RCC) is a highly vascularized tumour that is dependent on new vessel formation (angiogenesis) for growth and spread beyond the kidney (metastases). In recent years a new class of drugs have been developed which target the formation of this blood supply, stopping tumour growth and resulting in increased survival. These anti-angiogenic drugs such as Sunitinib, Pazopanib, Axitinib and Everolimus are now the standard of care in metastatic RCC (mRCC) in the United Kingdom.

Currently we assess if cancers are responding to treatment by looking at changes in the size of the tumour and metastases using computed tomography. However, the positive effects of drugs such as sunitinib do not always show a change in size, particularly early in treatment. Therefore we need to develop alternative methods for assessing if patients are responding in order to optimise individual management plans and prevent unnecessary toxicity and cost.

The aim of this study is to assess if three different functional magnetic resonance imaging (MRI) techniques are able to predict which patients will derive benefit from anti-angiogenic therapy early in their treatment. The study will recruit patients with mRCC who are going to be treated with anti-angiogenic drugs. These patients will have an MRI scan before they commence treatment and then a further scan after one treatment cycle (4 weeks) in addition to their normal clinical follow-up. The sequences being evaluated (arterial spin labeling, diffusion-weighted imaging and dynamic contrast imaging) look at the blood supply to the cancer and it is expected that there will be different changes in this blood supply in patients who are benefiting from treatment compared to those who are not responding. Early knowledge of response will help doctors choose the most appropriate treatment option for each individual patient.

Consenting patients with treatment naïve metastatic clear cell RCC will be recruited to the study. Before commencing anti-angiogenic therapy, patients will undergo 3 Tesla MRI covering the primary tumour or largest metastatic deposit identified from their staging CT examination if prior nephrectomy has been performed. Following 4 weeks of therapy (one treatment cycle), patients will undergo repeat MR imaging using the same protocol.