Cost effectiveness of microwave thermotherapy in patients with benign prostatic hyperplasia: part I-methods.

OBJECTIVES: To present the method used to evaluate the cost effectiveness, from the societal perspective, of transurethral microwave thermotherapy relative to medical therapy (alpha-blocking agents) and transurethral resection of the prostate (TURP) for a hypothetical cohort of 65-year-old men with moderate-to-severe benign prostatic hyperplasia (BPH) symptoms. METHODS: We constructed a decision-analytic Markov model with 25 health states describing the 3 treatments, 5 short-term clinical events, and 17 possible long-term outcomes. Each health state had an associated cost and utility. Utility weights, reflecting an individual's preference for a specific health outcome, range from 0, indicating death, to 100, indicating perfect health. Utility estimates were obtained by interviewing 13 men with moderate-to-severe BPH symptoms using the standard gamble preference measurement technique. On the basis of their risk attitudes, the patients were classified as risk averse or non-risk averse. The rates of remission, temporary and permanent adverse events, retreatment, and mortality were obtained from the Targis System (Urologix) randomized clinical trial, published reports, and a consensus panel. The costs during the 5 years after treatment initiation were estimated using national Medicare reimbursement schedules. The costs are reported in 1999 U.S. dollars. RESULTS: Eliciting utility values from patients with BPH was feasible and generated internally consistent and externally valid measures. In the non-risk-averse group, the utility value for significant remission, moderate remission, no remission, and worsening BPH symptoms without an adverse event was 99.1, 97.1, 94.4, and 87.3, respectively. As expected, the risk-averse individuals (n = 6) exhibited higher utility values than those in the non-risk-averse group (n = 7). In the non-risk-averse group, thermotherapy was the preferred treatment, and in the risk-averse group, medical therapy was preferred. In both groups, TURP was the least preferred therapy. The initial thermotherapy procedure costs without complications were estimated at $2629, and the initial TURP procedure costs without complications were estimated at $4597. Time-dependent probabilities were developed to reflect treatment durability. CONCLUSIONS: The resulting model parameters appear to be suitable for evaluating the cost effectiveness of thermotherapy relative to medical therapy and TURP in 65-year-old men with moderate-to-severe BPH symptoms.

Cost effectiveness of microwave thermotherapy in patients with benign prostatic hyperplasia: part II--results.

OBJECTIVES: To evaluate the cost effectiveness of transurethral microwave thermotherapy relative to medical therapy (alpha-blocking agents) and transurethral resection of the prostate (TURP) for patients with moderate-to-severe benign prostatic hyperplasia (BPH) symptoms. METHODS: A cost-effectiveness analysis was performed from the societal perspective for a hypothetical cohort of 65-year-old men with moderate-to-severe BPH symptoms. We calculated the incremental cost effectiveness of thermotherapy relative to medical therapy and TURP during 5 years after treatment initiation. Event probabilities were obtained from published reports, a consensus panel, and the Targis System (Urologix) randomized clinical trial. Costs were estimated using the national Medicare reimbursement schedules. Costs are reported in 1999 U.S. dollars. Total thermotherapy procedure costs were estimated at $2629. Quality-of-life and utility estimates were obtained by interviewing 13 patients with moderate-to-severe BPH symptoms. On the basis of their risk attitudes, patients were classified into risk-averse or non-risk-averse groups. The costs and health effects were discounted at 3% annually. RESULTS: In a hypothetical cohort of 10,000 non-risk-averse patients who were candidates for all three modalities, the 5-year costs were highest for patients undergoing TURP and lowest for those receiving medical therapy ($7334 and $6294, respectively). The thermotherapy group exhibited the highest 5-year utility value (53.52 quality-adjusted life-months). Compared with medical therapy, thermotherapy resulted in an additional 0.23 quality-adjusted life-months, with an incremental cost of $741. This yielded an incremental cost per quality-adjusted life-year gained of $38,664 for thermotherapy compared with medical therapy. Thermotherapy had a higher utility (difference of 1.71 quality-adjusted life-months) and lower cost (difference of $299) compared with TURP and thus was dominant over TURP. The results were similar for a hypothetical cohort of 10,000 risk-averse patients. CONCLUSIONS: From a societal perspective, thermotherapy appears to be a reasonable and cost-effective alternative to both medical and surgical treatment. However, the actual treatment decision should be based on multiple factors, only one of which is cost effectiveness.

A replication-defective variant of Moloney murine leukemia virus. I. Biological characterization.

We have studied the virus produced by a clone, termed 8A, that was isolated from a culture of murine sarcoma virus-transformed mouse cells after superinfection with Moloney murine leukemia virus (MuLV-M). Clone 8A produced high levels of type C virus particles, but only a low titer of infectious murine sarcoma virus and almost no infectious MuLV. When fresh cultures of mouse cells were infected with undiluted clone 8A culture fluids, they released no detectable pogeny virus for several weeks after infection. Fully infectious MuLV was then produced in these cultures. This virus was indistinguishable from MuLV-M by nucleic acid hybridization tests and in its insensitivity to Fv-1 restriction. It also induced thymic lymphomas in BALB/c mice. To explain these results, we propose that cone 8A is infected with a replication-defective variant of MuLV-M. Particles produced by clone 8A, containing this defective genome, can establish an infection in fresh cells but cannot produce progency virus at detectable levels. Several weeks after infection, the defect in the viral genome is corrected by back-mutation or by recombination with endogenous viral genomes, resulting in the formation of fully infectious progeny MuLV. The progeny MuLV'S that arose in two different experiments were found to be genetically different from each other. This is consistent with the hypothesis that, in each experiment, the progeny virus is formed clone 8A cells and assayed for infectivity by the calcium phosphate transfection technique. No detectable MuLV was produced by cells treated with this DNA. This finding, along with positive results obtained in control experiments, indicates that clone 8A cells do not contain a normal MuLV provirus.