99mTc-HYNIC Annexin-V imaging of tumors and its relationship to response to radiotherapy and/or chemotherapy

Aim. The aim of this study was to report on the relationship between preradiotherapy and prechemotherapy Tc-99m-HYNIC Annexin-V tumor uptake values, reflecting ongoing apoptosis, and outcome to radiotherapy and/or chemotherapy. Methods. Twenty-three cancer patients underwent staging examinations and a Tc-99m-HYNIC Annexin-V scintigraphy and subsequent radiotherapy and/or chemotherapy. Tumor-to-background ratios derived from tomographic Tc-99m-HYNIC Annexin-V images were related to treatment outcome as assessed by RECIST criteria. Results. Six patients underwent radiotherapy or radiochemotherapy: 4 exhibited response to treatment, 1 had stable, and 1 progressive disease. Corresponding tumor-to-background ratio's were respectively >= 2.3 (in responders), 1.2 in the patient presenting with stable disease and 1 in the patient presenting with progressive disease. Seventeen patients were treated by chemotherapy alone: 8 were progressive, 1 patient presented with stable disease and 8 responded to treatment. In 1/8 progressive patients a tumor-to-background ratio of 1.4 was found, the others showed no uptake. In the patient presenting with stable disease a ratio of 0.1 was found. in the 8 responders, 7 patients had a tumor-to-background ratio >= 1.3 whereas in 1 patient a ratio of 0.3 was found. Tumor-to-background ratios in responders (complete plus partial) (median 2.5, range: 0.3-4.2) were significantly higher when compared to those obtained in non-responders (stable plus progressive disease) (median 1, range: 0.1-1.4) (P<0.001). Conclusion. The findings presented suggest that Tc-99m-HYNIC Annexin-V pretreatment uptake may be useful to predict response to chemo- and radiotherapy.