Response after treatment with SIR-Spheres® Y-90 resin microspheres may be evaluated by CT, MRI, PET and/or changes in tumor markers.
CT images to show response to SIR-Spheres Y-90 resin microspheres in combination with systemic chemotherapy in a patient with colorectal liver metastases 1,2,3
Baseline CT scan pre-SIRT
CT scan 6 months post-SIRT
Anatomical criteria (Response Evaluation Criteria In Solid Tumors - RECIST) can be misleading and may lead to an underestimation of the pathological tumor response, especially if determined early (<3 months). Imaging evaluation that incorporated necrosis indicators reported that response to treatment can become apparent earlier (one month).4
Positron Emission Tomography (FDG-PET) has clinical value as an adjunct to CT in patients with FDG-avid tumors such as colorectal cancer as it detects response more rapidly and accurately. PET may also assist in differentiating viable neoplastic tissue from edema, hemorrhage or fibrosis.5
Diffusion-weighted MR imaging (DWI) has been shown to be capable of predicting therapeutic effects of SIRT in patients with colorectal liver metastases as early as 2 days after treatment.6
1. Sharma RA et al. J Clin Oncol 2007; 25: 1099-1106.
2. Sharma RA et al. Ann Oncol 2006; 17 (Sup 6): vi78 Abs. P-191.
3. Data on file; Sirtex Medical Limited.
4. Keppke et al. Am J Roentgenol 2007; 188: 768-775.
5.Bester et al. J Med Imaging Rad Onc 2011; 55: 111-118.
6. Dudeck et al. Eur Radiol 2010; 20: 2699-2706.