The dose of
gallium chloride required to inhibit
tumor growth after oral and chronic administration depends on the stage of the
cancer disease and of the type of
metastases. A dose regimen of 800 mg/24 h of
gallium chloride will provide serum
gallium concentrations greater than or equal to 600 micrograms/l in
lung cancer patients with a small and limited disease. A dose of 1,400 mg/24 h is well tolerated in metastatic patients but may not be high enough to reach the desired serum
gallium concentrations especially in patients with bone
metastases.
Radiotherapy and/or a
chemotherapy will permit one to increase the serum
gallium concentrations and the
tumor gallium uptake by reducing the volume of the
tumor. After chronic,
oral administration of
gallium a decrease in RBC Mg is noted. To avoid the Mg deficiency, the treatment must not be interrupted and may perhaps be decreased with care and slowly without resulting in a decrease of the serum
gallium concentrations provided the treatment has been prolonged over a sufficient time to enable one to induce intratumor
biological modifications and a decrease in the number of the malignant cells. Acute pharmacokinetic data are related to the histologic type of the
tumor and may not be used to predict the serum
gallium concentrations after chronic administration. The serum
gallium concentrations required to inhibit the
tumor growth may be higher in small cell lung
carcinomas than in nonsmall cell lung
carcinomas. Frequent Mg and Ga blood determinations are necessary to manage effective
gallium treatment.