4.2 Hyperthermia and metastasis
Local hyperthermia causes changes in the tumor microvasculature including increased
perfusion and changes in endothelial gap size (Kong et al., 2000; Reinhold, 1988).
Consequently, this may cause tumor cell shedding. The question, however, of whether local
hyperthermia increases the risk for metastasis is difficult to answer in clinical trials unless
the primary therapy has high probability for local control. The question of enhanced
metastases with hyperthermia has rarely been examined carefully in human clinical trials
where local or regional hyperthermia has been used, however, because many patients in
such series already had metastatic disease or had tumors with high likelihood for
development of them anyway. The conclusion that can be drawn regarding this issue is that
there is no evidence that local-regional hyperthermia causes an increase in metastases.
When whole-body hyperthermia is used, the issue is not resolved.