The Effect of Deep Inspiration Breath-hold on Tumour Oxygenation

Aim: To investigate the influence of deep inspiration breath-hold on the oxygen tension of in-vivo tumours measured using an Eppendorf pO 2histograph. Materials and methods: Patients with accessible primary or metastatic tumours ≥2 cm diameter were entered into a protocol measuring tumour oxygenation with an Eppendorf pO 2histograph during normal breathing (NB) and deep inspiration breath-hold (DIBH). Change in oxygen tension was assessed using the Wilcoxon Signed Ranks test. Results: Thirty patients were entered in to this protocol. The median maximum tumour dimension was 4 cm. The median of the median pO 2of these tumours was 18 mmHg. Tumours were assessed during NB and DIBH. Oxygen tension measurements along 1–3 pairs of tracks per tumour (median of 2) were obtained. The median number of measurements per track was 30 for NB and 29 for DIBH (range 17–59). In six tumours, the values during NB were significantly higher than during DIBH, whereas, for six other tumours, the relationship was the opposite; for the remaining 18 patients, no significant difference was observed. Conclusion: These data show heterogeneity of tumour oxygenation seen with in-situ tumours both at baseline and as a result of DIBH. No systematic change in the Eppendorf pO 2measurements was seen as a result of DIBH; however, the individual tumour responses to DIBH varied dramatically.