Discounting life-years: Whither time preference?

Abstract This paper employs classical concepts of diminishing marginal utility to demonstrate that risk-aversion can increase the perceived value of diagnostic procedures and thus raise optimum diagnostic expenditures. The theory is applied to a model in the spirit of Phelps and Mushlin\u27s initial technology assessments. The specific evaluation is the cost-effectiveness of somatostatin receptor scintigraphy used to detect distant metastases of carcinoid liver tumours in a patient otherwise eligible for surgical resection of the liver. Data for the model are taken from published sources and financial databases, when available, and otherwise from a senior clinician\u27s experience (LKK). The quantitative results indicate that receptor scintigraphy may have two beneficial impacts to risk-neutral individuals. First, it may reduce the combined costs of therapy and treatment because the diagnostic procedure costs less than the expected savings generated by avoiding inappropriate surgeries. Second, it may improve the patient\u27s expected health-status-adjusted life years (HSALY) because the information allows physicians to better match treatment to the cancer\u27s stage. Finally the paper demonstrates that risk aversion, as embodied in classical diminishing marginal utility applied to health status, can increase the value of the diagnostic tests and can lead the patient to choose a less beneficial treatment. An illustrative risk-averse utility function changed the optimum treatment from surgery to chemotherapy and increased scintigraphy\u27s benefit by 500%

Prognostic Validity of the American Joint Committee on Cancer Staging Classification for Midgut Neuroendocrine Tumors

Purpose: The American Joint Committee on Cancer (AJCC) staging manual has introduced a TNM staging classification for jejunal-ileal (midgut) neuroendocrine tumors (NETs). This classification has not been validated in a population consisting solely of midgut NETs. The purpose of this study was to test the prognostic validity of the classification in such a population. Methods: Patients with jejunal and ileocecal NETs who were treated at the Moffitt Cancer Center between 2000 and 2010 were assigned stages (I through IV). Kaplan-Meier analyses for overall survival (OS) were performed on the basis of TNM stage and pathologic grade. Multivariate modeling was performed using Cox proportional hazards regression. Results: We identified 691 patients with jejunal-ileocecal NETs. The AJCC classification in aggregate was highly prognostic for OS (P \u3c .001). Five-year OS rates for stages I through IV were 100%, 100%, 91%, and 72%, respectively. The survival difference between stages III and IV was significant (P \u3c .001); the difference between stages I/II versus III was not statistically significant (P = .1). Among patients with stage IIIB tumors, 5-year survival rates were 95% for resectable tumors versus 78% for unresectable mesenteric tumors (P = .02). A proliferative threshold of five mitoses per 10 high-power fields (HPF) was of greater prognostic value than a threshold of two mitoses per 10 HPF for discriminating between low- and intermediate-grade tumors. Conclusion: Stage I and II midgut NETs are associated with identical survival rates. Stage IIIB tumors are heterogeneous, with significant differences in survival observed between resectable mesenteric lymph nodes versus unresectable masses in the root of the mesentery. A higher mitotic cutoff of five per 10 HPF may lead to improved prognostic differentiation between low- and intermediate-grade tumors. Revisions to the current AJCC staging and grading classification may be warranted

Peptide receptor radionuclide therapy.

On their plasma membranes, cells express receptor proteins with high affinity for regulatory peptides, such as somatostatin. Changes in the density of these receptors during disease, for example, overexpression in many tumors, provide the basis for new imaging methods. The first peptide analogues successfully applied for visualization of receptor-positive tumors were radiolabeled somatostatin analogues. The next step was to label these analogues with therapeutic radionuclides for peptide receptor radionuclide therapy (PRRT). Results from preclinical and clinical multicenter studies already have shown an effective therapeutic response when using radiolabeled somatostatin analogues to treat receptor-positive tumors. Infusion of positively charged amino acids reduces kidney uptake, enlarging the therapeutic window. For PRRT of CCK-B receptor-positive tumors, such as medullary thyroid carcinoma, radiolabeled minigastrin analogues currently are being successfully applied. The combination of different therapy modalities holds interest as a means of improving the clinical therapeutic effects of radiolabeled peptides. The combination of different radionuclides, such as (177)Lu- and (90)Y-labeled somatostatin analogues, to reach a wider tumor region of high curability, has been described. A variety of other peptide-based radioligands, such as bombesin and NPY(Y(1)) analogues, receptors for which are expressed on common cancers such as prostate and breast cancer, are currently under development and in different phases of (pre)clinical investigation. Multireceptor tumor targeting using the combination of bombesin and NPY(Y(1)) analogues is promising for scintigraphy and PRRT of breast carcinomas and their lymph node metastases