Cost-Effectiveness Analysis of Stereotactic Ablative Body Radiation Therapy Compared With Surgery and Radiofrequency Ablation in Two Patient Cohorts: Metastatic Liver Cancer and Hepatocellular Carcinoma.

AIMS: To compare the cost-effectiveness of stereotactic ablative body radiation therapy (SABR) with radiofrequency ablation and surgery in adult patients with metastatic liver cancer and hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Two patient cohorts were assessed: liver oligometastases and HCC. For each patient cohort, a decision analytic model was constructed to assess the cost-effectiveness of interventions over a 5-year horizon. A Markov process was embedded in the decision model to simulate the possible prognosis of cancer. Data on transition probabilities, survival, side-effects, quality of life and costs were obtained from published sources and the SABR Commissioning through Evaluation (CtE) scheme. The primary outcome was the incremental cost-effectiveness ratio with respect to quality-adjusted life-years. The robustness of the results was examined in a sensitivity analysis. Analyses were conducted from a National Health Service and Personal Social Services perspective. RESULTS: In the base case analysis, which assumed that all three interventions were associated with the same cancer progression rates and mortality rates, SABR was the most cost-effective intervention for both patient cohorts. This conclusion was sensitive to the cancer progression rate, mortality rate and cost of interventions. Assuming a willingness-to-pay threshold of £20 000 per quality-adjusted life-year, the probability that SABR is cost-effective was 57% and 50% in liver oligometastases and HCC, respectively. CONCLUSIONS: Our results indicate a potential for SABR to be cost-effective for patients with liver oligometastases and HCC. This finding supports further investigation in clinical trials directly comparing SABR with surgery and radiofrequency ablation.

Radiotherapy for choroidal melanoma. An 18-year experience with radon.

Twenty-three patients were treated with radon therapy for choroidal melanoma at the Ohio State University Hospitals, Columbus, between 1968 and 1976. We present an 18-year experience, including follow-up of at least eight years, in all those receiving therapy. Three patients (13%) died of metastatic disease. Four patients (17.4%) died of other causes. Sixteen patients (69.6%) were alive, with no signs of metastatic disease. Eight patients subsequently required enucleation due to inadequate tumor response. Of the 15 patients who demonstrated successful tumor destruction and retained their eyes, 13 (86.7%) developed substantial irradiation-induced retinopathy, including hard exudates, telangiectasias, neovascularization, microaneurysms, intraretinal and vitreous hemorrhages, secondary glaucoma, and irradiation-induced cataract. Our long-term results indicate a high incidence of both vascular complications and decreased visual acuity.

A study of dose distribution patterns from cobalt-60 and Varian Clinac-4 beams.

Dose distribution patterns of 4 MV x-rays from a Varian Clinac 4 linear accelerator are compared with those from a 60Co teletherapy machine. Field flatteners of lead and depleted uranium were used. Dose distribution maps display the off-axis high dose or "horns" with lead filters and circular dose distribution patterns. The uranium field flattener clearly "clipped the horns" and eliminated circular dose distribution patterns with larger fields.

An analysis of the dosimetry for mantle field therapy using 4 MV X-rays and its routine application.

There are several different methods in vogue at present in determining patient midplane doses in the "mantle" treatment for Hodgkin's disease and malignant lymphomas. A method of determining midplane doses in individual cases using thermoluminescent dosimetry is presented. It shows excellent agreement with the midplane doses measured in an Alderson-Rando phantom treated as a hypothetical "mantle" patient.

Determination of hydroxyl radical production in aqueous solutions irradiated to clinically significant doses.

Decarboxylation of 14C-carboxylbenzoic acid in aqueous solutions after low-dose irradiation has been used to determine the relative magnitude of oxidation reactions and estimate the hydroxyl radicals produced. The G CO2 values determined from these measurements of 0.4 to 1.0 mM solutions of benzoic acid after x-ray doses of 1000 rads ranged from 0.72 to 0.77, in excellent agreement with values reported by authors using much higher doses of radiation. Superoxide dismutase and catalase, known scavengers of superoxide and hydrogen peroxide, respectively, did not show impairment of the oxidation of benzoic acid. On the other hand, biologically significant concentrations of phenol and mannitol appear to impair the radiation-induced oxidation of benzoic acid, indicating that the process is secondary to a reaction with OH . . We found that serum and glucose, common cell media contents, are potent OH . scavengers. These observations indicate that the oxidation of benzoic acid can be as a reliable method to estimate OH . with radiation doses of clinically significant magnitudes. In addition, these results suggest that the radiation induced by OH . in cell systems can be significantly modified by the type of buffer used.

Dosimetry disparities resulting from two accepted methods of calibration of cobalt-60 teletherapy machines.

The primary concern of all involved in the management of radiotherapeutic patients is that the tumor dose delivered to each and every patient in one institution is identical to that delivered anywhere else. Despite the advocacy 1,2,3,4 for the calibration of high energy photon beams at 5 cm depth or beyond in a water phantom to reduce the effect of electron "contamination" from collimators, filters, applicators, etc., the "in-air" method of calibration is still in vogue in many institutions in the United States and elsewhere. The introduction of S.I. units in radiology is likely to create ambiguity in proper conversion factors from exposure to absorbed dose which can be avoided if field instruments are calibrated in terms of absorbed dose in water under specified conditions. The present study shows that the estimated error can be as much as 7% low when the "in-air" method of calibration is used instead of measurements in a large water phantom at 5 cm depth for cobalt-60 photon beams and hence recommends that the procedure for "in-air" calibration for high energy photon beam should be discontinued.