Prevention of Systemic Toxicity in Hyperthermic Isolated Lung Perfusion using Radioisotopic Leakage Monitoring.

RATIONALE: Hyperthermic isolated lung Perfusion (ILuP) is used to deliver high-dose chemotherapy to pulmonary metastases while sparing systemic toxicity. Accurate leakage monitoring is however necessary. This study aimed to verify the accuracy of radionuclide leakage monitoring in patients undergoing ILuP, by comparing this method with serial blood sampling. METHODS: A total of 15 consecutive ILuP procedures were performed on eleven patients affected by lung metastases from soft tissue sarcoma. After establishing isolated perfusion, erythrocytes of systemic blood (SB) were labeled with 0.2 MBq/kg of 99mTc. The baseline SB counting rate (CR) was assessed using a ?-probe. Subsequently, erythrocytes of the circuit blood (CB) were labeled with 2 Mbq/kg of 99mTc. Radioactivity leakage factor (RLF) was continuously measured using a formula, accounting for CR, systemic/circuit activity ratio and total/systemic volume ratio. The TNF-? concentration in SB and CB was measured by Enzyme-linked Immunosorbent Assay (ELISA) throughout the procedure. RESULTS: RLF averaged 2.3±1.5%, while the systemic/circuit TNF-? ratio was 0.05±0.12%. These two indices were strictly correlated in all of the procedures (average R-value 0.88±0.07). RLF exceeded 5% during 3 of 15 procedures, prompting the application of compensatory maneuvers. ELISA confirmed a marked increase in systemic TNF-? levels in these patients (2.6±3.5 ng/ml). Conversely, patients whose RLF did not exceed the 5% threshold presented a mean TNF-? of 0.02±0.005 ng/ml (p < 0.01). CONCLUSIONS: In patients submitted to ILuP, RLF monitoring is feasible and accurate. Moreover, it grants immediate results, permitting for the adoption of corrective maneuvers for leakage, thus minimizing toxicity.