Antitumoral Local Effect and Metastatic Risk of Focused Extracorporeal Pyrotherapy on Dunning R-3327 Tumors

The Dunning model

“…Pyrotherapy, a method which destroys tissue by heating implanted, metal-coated seeds with an external oscillating magnetic field, has also been explored as a treatment modality using this model [58,59]. Studies using the Dunning model have suggested that the combination of hyperthermia and irradiation may have an additive or synergistic effect [59][60][61]. Another form of pyrotherapy which employs high-energy ultrasound that is generated extracorporeally and focused on the target tissue has also been evaluated in this model [63][64][65].…”

Circulating tumor cells in patients with solid malignancy treated by high-intensity focused ultrasound

“…Although early study showed an enhancement of metastases after HIFU ablation (Fry and Johnson 1978), recent experimental studies did not confirm this adverse effect. On the contrary, a lower metastatic rate in animals treated with HIFU was observed as compared with the control group (Bataille et al 1996;Chapelon et al 1992;Child et al 1982;Goss and Fry 1984;Oosterhof et al 1997;Smachlo et al 1979;Yang et al 1991). These results revealed that HIFU ablation did not increase metastatic risk in animal experiments.…”

“…However, because HIFU cavitation is one of the main ablative mechanisms, controversy remains surrounding the hypothesis that exposure of a solid malignancy to HIFU could lead to an increase of metastases. Most experimental studies have shown that HIFU did not enhance the potential risk of metastasis (Bataille et al 1996;Chapelon et al 1992;Child et al 1982;Goss and Fry 1984;Oosterhof et al 1997;Smachlo et al 1979;Yang et al 1991), but one study performed by Fry and Johnson (1978) suggested the opposite. To our knowledge, no clinical study to date has explored the safety of HIFU in the treatment of patients with solid malignancies with an emphasis on assessment of this metastatic risk.…”

Influence of High-Intensity Focused Ultrasound on the Development of Metastases

“…In orther studies no increased metastatic rate could be seen [3,4,7,8]. The results of such studies should be inter preted critically for several reasons: (1) some of the tumor models used have never shown any metastatic potential, and it is, therefore, questionable whether such a tumor is appropriate for evaluating the influence of HIFU on metastasis formation; (2) potentially metastasizing tu mors should be exposed to HIFU during the early phase of the metastasizing process in order to be able to quantify size and number of (lung) métastasés, and (3) only tumors that metastasize to only one organ should be used to ensure that all métastasés are taken into account.…”

“…Moreover, in the treated group métastasés only occurred in animals with local relapse. Also Bataille et al [8] found no increased metastatic rate after HIFU exposure of MatLyLu and G cell Dunning R3327 tumors. These results suggest that HIFU does not enhance the risk for métastasés.…”