Platinum compounds as radiosensitizers in strontium-89 metabolic radiotherapy.

PURPOSE: Strontium-89 is currently used for the treatment of painful bone metastases. This study reports on two preliminary experiences with low-dose platinum compounds, carboplatin and cisplatin, as radiosensitizers in 89Sr therapy. PATIENTS AND METHODS: 30 patients entered the carboplatin study: 15 patients (Group A) were treated with 148 MBq 89Sr followed by carboplatin (100 mg/m2 at 7 and 21 days) and 15 patients (Group B) were treated with 89Sr alone. 12 patients entered the cisplatin study: six patients (Arm 1) received 148 Mq 89Sr plus cisplatin (50 mg/m2) in two administrations (immediately before and 10 days after 89Sr injection) and six patients (Arm 2) received 89Sr plus two placebo administrations. Pain response was assessed 8 weeks after the therapy on the Wisconsin score modifications. RESULTS: No clinically significant adverse effects or myelosuppression by platinum compounds were observed. In carboplatin study a pain response was observed in 20 of 27 (74%) evaluable patients, 13/15 in group A and 7/12 in group B. The pain response in the patients treated with 89Sr and carboplatin was clearly superior to that seen in the patients treated with 89Sr alone (P = 0.025), whereas survival was only marginally better in the combined treatment group (8.1 vs 5.7 months, P = 0.19). In cisplatin study a pain response was observed in 10 of 12 (83%) evaluable patients, 5/6 in Arm 1 and 4/6 in Arm 2. CONCLUSIONS: Low-dose platinum compounds seem to enhance the effects of 89Sr radioisotope therapy on pain from bone metastases without relevant hematological toxicity.

111In-octreotide scintigraphy in pituitary adenomas.

This study reports on 111In-octreotide scintigraphy in 20 patients affected with pituitary adenomas, including tracer uptake ratios and in vitro immunohistochemical characterization of the matostatin receptor state. 111In-octreotide uptake was already observed at 4 hours in 7/8 GH-secreting adenomas, in 5/7 non-secreting adenomas and in 1/5 prolactinomas. Concordance between the scan and the histochemical results was observed in all cases. The uptake ratios evaluated at 24 hours ranged from 2.3 to 4.2. The following conclusions were drawn: 1) 111In-octreotide is a suitable tracer to evaluate the somatostatin receptor state of pituitary adenomas; 2) Semi-quantitative measures of tracer uptake can be easily obtained with static planar scanning, but more refined techniques are needed for receptor kinetics evaluation; 3) This nuclear technique is a promising non-invasive tool to identify patients with somatostatin receptor positive pituitary adenomas who might potentially benefit from pre- and/or post-surgery cold octreotide medical treatment.