Regional Hyperthermia With Neoadjuvant Chemotherapy for Treatment of Soft Tissue Sarcoma

To the Editor Issels et al analyzed long-term local progression-free survival (LPFS), disease-free survival (DFS), and overall survival (OS) data from an important clinical trial evaluating the efficacy of regional hyperthermia (RHT) added to neoadjuvant chemotherapy (NACT) for localized high–risk soft tissue sarcoma. In the article, added value from RHT was summarized mainly with hazard ratios (HRs). For instance, for DFS, an HR of 0.71 was reported (95% CI, 0.55-0.93; P = .01) in favor of RHT. Median DFS times were 2.8 (95% CI, 2.0-4.9) and 1.5 years (95% CI, 1.1-2.1) for NACT with RHT and NACT alone, respectively. These median CIs overlap, indicating that the difference in median DFS time might not be statistically significant. For OS, the HR was 0.73 (95% CI, 0.54-0.98; P = .04), but median OS time for NACT with RHT was not available. In panels A to C of Figure 2 from the study by Issels et al, the Kaplan-Meier curves of the 2 arms appeared to be parallel after 3 years. Moreover, as noted in the article, NACT with RHT showed delayed OS benefit. These factors suggest that HRs are not constant over time and are difficult to interpret clinically as summary measures for treatment effect.

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