and absorbed doses in lesions on CXCR4-directed imaging and radionuclide therapies to date, the markedly increased SUVobserved in certain cases suggests that a substantial fraction of patients may also be eligible for CXCR4-directed radioligand therapies. However, CXCR4-targeted endoradiotherapy causes bone marrow ablation and, thus, subsequent stem cell support is needed , further emphasizing the importance of well-established algorithms for adequate patient selection.
Future studies should also evaluate the ability of CXCR4-directed molecular imaging to assess the retention capacities of nonradiolabeled CXCR4 neutralizing agents in vivo, preferably before treatment onset. For instance, a phase I study evaluating the CXCR4 inhibitor LY2510924 in patients with advanced solid cancers revealed favorable antitumor activity .
Our study has several limitations. We included both CT- and MR-based hybrid imaging, which may provide an additional variable that could be controlled better in future studies. Despite investigating the largest cohort to date, prospective trials should also be undertaken. In addition, the numbers of investigated patients per tumor entity substantially varied.