Clinical experience with strontium-89 in prostatic and breast cancer patients.

Bone metastases are a major problem in the clinical management of patients with breast or prostate cancer. Severe bone pain can be a particularly debilitating effect of metastatic disease, resulting in a growing dependency on opioid analgesics and a reduced quality of life in patients who have a short time to survive. The radiopharmaceutical strontium-89 has been demonstrated to be generally well tolerated as well as effective in reducing metastatic bone pain in breast or prostate cancer patients. Unlike other radioisotopes or external radiation treatments, it represents systemic, targeted therapy that is simple and fast to administer in an outpatient setting. Data accumulated over the last 15 years demonstrates that 89Sr provides pain relief in up to 80% of patients with bony metastases arising from breast or prostatic malignancies. Pain palliation is maintained for several months, along with improvements in functional status and quality of life. As many as one fifth of 89Sr-treated patients become pain free and require no further pain medication. The adverse effects of intravenous 89Sr are minimal. Bone marrow toxicity is observed in many patients, resulting in some reduction of platelet and white blood cell counts. Despite reductions of 20% to 30%, these hematologic effects are generally reversible and the majority of patients maintain platelet counts that are within normal limits. Strontium-89 is effective systemic radioisotopic therapy for the palliation of painful bony metastases from breast and prostate carcinoma.

A Bayesian hierarchical assessment of gastric emptying with the linear, power exponential and modified power exponential models.

BACKGROUND: Many studies assessed gastric retention over time utilizing different models, mostly with scintigraphic measures at varied endpoints from limited number of normal volunteers. With a standardized 4-h gastric emptying (GE) protocol, we compared model fit by the linear, power exponential (PE), and modified power exponential (MPE) models to contrast differences in GE among different groups based on clinical diagnosis and gender. METHODS: We retrospectively collected 320 patient records with four consecutive hourly scintigraphic measures of percent intragastric residual at the Kansas University Medical Center. We obtained parameter estimates with the Bayesian hierarchical models using informative priors from previous research. KEY RESULTS: The PE or MPE model captured the time dependent GE rate better than the linear model. The estimated GE rates more than doubled for those without gastroparesis compared to patients diagnosed with gastroparesis. Males tended to empty gastric content faster but were not significantly different from females at the 5% level. CONCLUSIONS & INFERENCES: The point estimates and 95% credible interval for GE rates obtained with the PE and MPE models may provide an alternative diagnostic tool for clinicians since it utilizes gastric emptying scintigraphy measures at multiple endpoints which may be sensitive to different aspects of the disease. No agreement in lag phases was obtained by the three models based on respective definitions from previous researches, but similar results would be obtained with the PE and MPE models if both defined lag phase by back projecting the regression lines to the same gastric retention level.

Mechanisms of symptomatic improvement after gastric electrical stimulation in gastroparetic patients.

The aims were to investigate the effects of gastric electrical stimulation (GES) on autonomic function, gastric distention and tone, and central control mechanisms in gastroparetic patients. Ten gastroparetic patients refractory to standard medical therapy participated in this study and data were collected at baseline, within two weeks before surgery for implantation of GES system, and at follow-up sessions between 6 and 12 weeks after GES therapy was initiated. In each session, electrocardiogram, electrogastrogram (EGG) and gastric barostat measurements were conducted before and after a caloric liquid meal. Positron Emission Tomography (PET) brain scans were performed on a separate day. During GES therapy there was a significant increase in the discomfort threshold for mean pressure from 21 mmHg at baseline to 25 mmHg at follow-up, and for mean volume from 561 mL to 713 mL. A significant increase in the postprandial EGG power (amplitude) was observed between baseline and follow up. The sympathovagal balance was significantly decreased after GES therapy, indicating a significant increase in vagal activity. The cumulative PET data showed an increase in quantitative radioactive counts relative to the standardized data base in both the thalamic and caudate nuclei after chronic GES therapy. We conclude that our data suggest that the symptomatic improvement achieved by GES in gastroparesis is best explained by activation of vagal afferent pathways to influence CNS control mechanisms for nausea and vomiting accompanied by enhanced vagal efferent autonomic function and decreased gastric sensitivity to volume distention which enhances postprandial gastric accommodation.