Hypothesis: Is heroin a 'barrier' against cancer? A retrospective analysis of heroin-addicted individuals untreated for opioid dependence between 2001-2010.

PURPOSE: The findings of previous studies attracted our interest in searching and defining the percentage of deaths from cancer in 'heroin regular addicts' i.e. those who had never stopped taking the drug since they started. METHODS: The archives of the Greek Reitox Focal Point of the years 2001 to 2010 were retrospectively searched, focusing on the number of deaths from cancer of the regular heroin addicts. RESULTS: The records from 2,321 regular heroin addicts showed that none of them died from cancer. It seems that heroin might act as a "barrier" against cancer. CONCLUSION: Further studies are needed to confirm our results and to explore the potential cause for this surprising finding.

Comparative evaluation of 99mTc-depreotide and 201Tl chloride single photon emission tomography in the characterization of pulmonary lesions.

PURPOSE: To compare (99m)Tc-depreotide and (201)Tl chloride SPET in the characterization of pulmonary lesions. METHODS: Fifty-seven pulmonary lesions from 33 patients suspected of malignancy in computed tomography, were assessed by (99m)Tc-depreotide and (201)Tl early and delayed SPET imaging. Images were visually assessed and the tumour-to-normal (T/N) lung activity ratio for early (ER) and delayed (DR) scans and the retention index (RI), were calculated in every lesion. A final diagnosis was reached for all lesions, based either on histology or prolonged clinical and radiological follow-up. RESULTS: Twenty-three lesions were characterized as malignant and 34 benign. In visual analysis, all malignant lesions accumulated both tracers resulting in sensitivity and negative predictive values of 100%. However, false positive interpretations resulted in a specificity of 64.7% and 67.6% for (99m)Tc-depreotide and (201)Tl, respectively. ER and DR of both agents and the RI of (99m)Tc-depreotide were significantly higher in malignant, compared to benign lesions. In defining thresholds of abnormality from ROC analysis, a significant increase in specificity was observed for both tracers in both scan phases (91.2% for all), as compared to visual analysis (P<0.01). There was no significant difference in the diagnostic performance between (99m)Tc-depreotide DR and (201)Tl DR, although the former provided the highest T/N ratio. CONCLUSION: This study demonstrates that (99m)Tc-depreotide and (201)Tl SPET are equally effective and may be useful in the non-invasive determination of lung malignancy. The specificity of both techniques is significantly improved by quantifying radiopharmaceutical accumulation in pulmonary lesions.