Objective: Hypoxia is a characteristic of many tumors and portends a worse prognosis in lung, cervical, prostate, and rectal cancers. Unlike the others, lung cancers present a unique challenge in measuring hypoxia, with invasive biopsies and higher rates of complications. Noninvasive imaging studies detecting hypoxia using isotopes of copper-diacetyl-bis(N4-methylthiosemicarbazone) ((62)Cu-ATSM) have predicted prognosis and treatment outcomes in some small feasibility trials. These images, however, may not identify all areas of hypoxia. Hence, we hypothesize that the addition of another PET imaging agent, copper-pyruvaldehyde-bis(N4-methylthiosemicarbazone) ((62)Cu-PTSM), which can detect areas of perfusion, can augment the information obtained in (62)Cu-ATSM PET scans.
Subjects and methods: To characterize tumors on the basis of both perfusion and hypoxia, 10 patients were studied using both (62)Cu-ATSM and (62)Cu-PTSM PET scans. In addition, proteomic arrays looking at specific proangiogenic, survival, and proinflammatory targets were assessed.
Results: Six of 10 patients had evaluable PET scans. Our initial experience of characterizing lung tumor hypoxia using (62)Cu-ATSM and (62)Cu-PTSM PET scans showed that visualization of areas with hypoxia normalized for perfusion is feasible. All studied tumors exhibited some hypoxia. Despite the small sample size, a positive relationship was noted between epidermal growth factor levels and (62)Cu-ATSM-detected hypoxia.
Conclusion: This initial series of (62)Cu-ATSM and (62)Cu-PTSM PET scans shows that evaluating lung masses by visualizing hypoxia and perfusion is a feasible and novel technique to provide more information. Further investigation is warranted to assess the potential role of (62)Cu-ATSM and (62)Cu-PTSM PET techniques combined with proteomics as alternatives to invasive biopsy techniques in clinical care.