To determine the influence of the length of the treatment on the anatomopathological and biochemical intratumor changes induced by
gallium, we treated C3H BA mammary
adenocarcinoma-bearing C3H/HeJ mice with
gallium chloride daily, for a period of either 21 or 42 days. In both cases the same dose of 200 mg/kg/24h was administered. An increase of
collagen fibrosis in treated
tumors as opposed to controls was only noted after 42 days, as well as a significant decrease of the intratumor
magnesium and
calcium concentrations that could be responsible for a reduction in the metabolic activities of the malignant cells. Remarkable intratumor
gallium concentrations (38.4 +/- 30.3 nmol/g after 21 days of treatment; 13.4 +/- 7.3 nmol/g after 42 days where the
necrosis is much more important) are obtained after this
oral administration. There is no renal toxicity and a higher
tumor/kidney concentration ratio is obtained than after acute parenteral administration. The effect of
gallium may be different according to the mode of administration: it may be more cytotoxic after parenteral administration, while after
oral administration it may act as a better metabolic regulator with a more selective
tumor uptake and fewer side effects.