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Purpose: Hyperthermic isolated limb perfusion (ILP) with recombinant tumour necrosis factor alpha (TNF) and melphalan contributes to limb-saving treatment in patients with locally advanced extremity soft tissue sarcoma (STS). This study was conducted to evaluate the dynamic changes of tumour oxygenation and temperature during ILP and their effects on treatment response. Patients and methods: Tumour oxygenation (pO2) and tumour temperature were measured by intratumourally placed O2-sensitive catheter electrodes in 34 patients who underwent ILP for locally advanced or recurrent STS. Tumour response to ILP was assessed by the fraction of tumour necrosis in the resection specimen. Results: Mean tumour pO2 prior to application of TNF and melphalan was 36 mm Hg (range: 2-116 mm Hg) and dropped significantly to 13 mm Hg (range: 0-67 mm Hg, p = 0.03) during ILP. Mean tumour tissue temperature increased from 34.4°C (range 32.4-36.4) to 38.5°C (range 34.1-40.4, p = 0.0001). The mean fraction of necrosis in the resection specimen was 65% (range 5-99). Only the tumour tissue temperature at the onset of ILP correlated with the extent of tumour necrosis ( p = 0.01). Conclusion: ILP with TNF and melphalan induces severe oxygen deprivation in soft tissue sarcoma. However, changes in tumour oxygenation did not correlate with treatment response. [ABSTRACT FROM AUTHOR]

Tumour blood flow before and during clinically relevant mild hyperthermia exhibits pronounced heterogeneity. Flow changes upon heating are not predictable and are both spatially and temporally highly variable. Flow increases may result in improved heat dissipation to the extent that therapeutically relevant tissue temperatures may not be achieved. This holds especially true for tumours or tumour regions in which flow rates are substantially higher than in the surrounding normal tissues. Changes in tumour oxygenation tend to reflect alterations in blood flow upon hyperthermia. An initial improvement in the oxygenation status, followed by a return to baseline levels (or even a drop to below baseline at high thermal doses) has been reported for some tumours, whereas a predictable and universal occurrence of sustained increases in O2 tensions upon mild hyperthermia is questionable and still needs to be verified in the clinical setting. Clarification of the pathogenetic mechanisms behind possible sustained increases is mandatory. High-dose hyperthermia leads to a decrease in the extracellular and intracellular pH and a deterioration of the energy status, both of which are known to be parameters capable of acting as direct sensitisers and thus pivotal factors in hyperthermia treatment. The role of the tumour microcirculatory function, hypoxia, acidosis and energy status is complex and is further complicated by a pronounced heterogeneity. These latter aspects require additional critical evaluation in clinically relevant tumour models in order for their impact on the response to heat to be clarified. [ABSTRACT FROM AUTHOR]