Investigators in the Melanoma Research Program are exploring options to improve melanoma diagnostics through imaging interpretation for certain patients on immunotherapy.
In particular, researchers are studying a specially labeled interleukin-2 that could aid in tumor measurement diagnostics for melanoma patients.
Although new immunotherapy agents have changed the landscape of metastatic melanoma treatment in recent years, challenges remain in accurately determining true radiologic progression from inflammatory pseudoprogression in some melanoma patients.
In clinical trials related to these new immunotherapy agents, researchers noted that early (on-therapy) tumor volume enlargement as measured by computerized tomography (CT) didn't necessarily predict tumor progression. In many cases, such changes on CT imaging were attributed to tumor inflammation (tumor infiltration by activated T cells), which later led to tumor size reduction, in part explaining the discrepancy between overall survival and progression-free survival in these trials.
This has resulted in a national effort to modify existing clinical trial tumor response criteria (Response Evaluation Criteria in Solid Tumors, or RECIST) to take into account the possibility of tumor enlargement as a result of inflammation induced by immunotherapeutics.
However, there is no clinically reliable tool currently available to differentiate between tumor enlargement due to tumor progression and tumor enlargement due to tumor inflammation.
Melanoma research underway at Mayo Clinic suggests that interleukin-2 imaging may help improve imaging interpretation for patients on immunotherapy.
Interleukin-2 Imaging as a Guide to Cancer Immunotherapy in Advanced Melanoma: A Pilot Study
Svetomir N. Markovic, M.D., Ph.D.
Many patients undergo immunotherapy as part of their treatment for metastatic melanoma. Unfortunately, many modern imaging methods used to assess response may lead to inaccurate results, possibly causing patients who are thought to have early tumor progression to unnecessarily and prematurely withdraw from what could actually be a viable treatment.
Researchers at Mayo Clinic and their collaborators are exploring the utility of using a specially labeled interleukin-2 to better visualize and differentiate tumors that are truly progressing from tumors that are increasing in size because of lymphocyte infiltration in patients undergoing systemic immunotherapy for metastatic melanoma.