ESTRO meets Asia 2024 - Abstract Book

S74

Interdisciplinary – Breast

ESTRO meets Asia

median temperature T50 of ~40.5°C), with an IQR between 2.4–15.9 minutes. Continuous TD parameter analysis showed that a higher TD was significantly associated with an increasing LRC ( P =0.001, Figure 1). Univariate and multivariate Weibull regression analysis showed that over the continuous TD range a twofold increase of TD (equivalent to a ~0.5°C temperature increase) was associated with a decrease of 47% (hazard ratio, 95% confidence interval (CI) 18%-84%) and 28% in hazard ratio for LRR (adjusted hazard ratio, 95% CI 4%-56%), respectively. Bayesian survival regressions lead to a range of comparable decreasing hazard ratios of recurrence when TD increased. These findings were robust under both an optimistic and a skeptic informative prior assumption on the effect of TD. Logistic regression analysis showed a protective effect of the HT treatment as the TD increases (Figure 2).

Conclusion:

Twofold increase of hyperthermia TD was associated with a significant increase in LRC over the continuous TD range during hyperthermia treatment and postoperative re-irradiation in LRR breast cancer. This result has implications for the importance of achieving excellent dose control during treatment delivery and is suggestive for a therapeutically relevant molecular hyperthermia effect in treatment with re-irradiation and hyperthermia.

Keywords: Recurrent breast cancer, thermal dose-effect

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