Boron neutron capture therapy of the rat 9L gliosarcoma: evaluation of theeffects of shark cartilage

A number of anti-angiogenic substances are now under evaluation, both exper imentally and clinically, as potential agents for the treatment of cancer. It has recently been demonstrated that anti-angiogenic agents can increase the therapeutic potential of photon irradiation in a range of tumour models . In the present communication a preliminary assessment is made of the effe cts of shark cartilage on the response of the rat 9L gliosarcoma to boron n eutron capture therapy (BNCT). Shark cartilage was administered orally as a n aqueous suspension at a daily dose of similar to 2000 mg kg(-1) body weig ht. The mean survival time of rats receiving no treatment was 20.7+/-0.5 da ys post intracranial tumour implantation. Administration of shark cartilage alone extended the survival time. Two of the rats treated with shark carti lage were healthy and fully active at the end of the evaluation period (43 days post implantation). At autopsy the brain tumours of these animals were a factor of similar to 4 smaller than controls. In a repeat study with sha rk cartilage alone the survival time was extended by approximately 30%. Aft er boronophenylalanine-mediated BNCT, with or without shark cartilage, the survival time of rats that eventually became moribund was increased by a fa ctor of similar to 2 relative to controls. In both treatment groups similar to 20% of rats were healthy at 1 year after BNCT. There was no evidence of residual tumour at post-mortem It was concluded that shark cartilage, when given alone, significantly increased the survival time of tumour-bearing r ats, presumably owing to an antiangiogenic effect. However, the survival da ta suggested that boronophenylalanine-mediated BNCT did not appear to be en hanced by the administration of shark cartilage.