Reduction of prostate intrafraction motion using gas-release rectal balloons.

PURPOSE: To analyze prostate intrafraction motion using both non-gas-release (NGR) and gas-release (GR) rectal balloons and to evaluate the ability of GR rectal balloons to reduce prostate intrafraction motion. METHODS: Twenty-nine patients with NGR rectal balloons and 29 patients with GR balloons were randomly selected from prostate patients treated with proton therapy at the University of Florida Proton Therapy Institute (Jacksonville, FL). Their pretreatment and post-treatment orthogonal radiographs were analyzed, and both pretreatment setup residual error and intrafraction-motion data were obtained. Population histograms of intrafraction motion were plotted for both types of balloons. Population planning target-volume (PTV) margins were calculated with the van Herk formula of 2.5Σ + 0.7σ to account for setup residual errors and intrafraction motion errors. RESULTS: Pretreatment and post-treatment radiographs indicated that the use of gas-release rectal balloons reduced prostate intrafraction motion along superior-inferior (SI) and anterior-posterior (AP) directions. Similar patient setup residual errors were exhibited for both types of balloons. Gas-release rectal balloons resulted in PTV margin reductions from 3.9 to 2.8 mm in the SI direction, 3.1 to 1.8 mm in the AP direction, and an increase from 1.9 to 2.1 mm in the left-right direction. CONCLUSIONS: Prostate intrafraction motion is an important uncertainty source in radiotherapy after image-guided patient setup with online corrections. Compared to non-gas-release rectal balloons, gas-release balloons can reduce prostate intrafraction motion in the SI and AP directions caused by gas buildup.

Costs of treatment and outcomes associated with second-line therapy and greater for relapsed ovarian cancer.

OBJECTIVES: Most women with epithelial ovarian cancer (EOC) will develop disease progression or recurrence with resistance to platinum therapy. We report overall costs and treatment outcomes associated with topotecan or gemcitabine administration in platinum- and paclitaxel-resistant EOC patients. METHODS: Patients who received topotecan (n = 51) or gemcitabine (n = 56) as second-line therapy or greater for platinum- and paclitaxel-resistant EOC were retrospectively identified. Per patient costs for each regimen were determined and compared. RESULTS: The mean total direct cost per cycle per patient of gemcitabine was $2732.28, with a median total direct cost per cycle of $1382.73. The mean total direct cost per cycle per patient of topotecan was $7832.07, with a median total direct cost per cycle of $4219.02. By comparison of the means, total direct cost per cycle per patient was significantly more expensive for topotecan (P = 0.001). Fifty-six patients received a total of 415 cycles of gemcitabine, median 5 cycles per patient (range, 1-59). Thirteen (23.2%; 95% CI, 11.9-34.5%) of 56 patients displayed clinical benefit, with median PFS of 1.8 months and median overall survival (OS) of 8.2 months. Fifty-one patients received topotecan, for a total of 264 cycles, median 4 cycles per patient (range, 1-42). Twenty-eight (56%; 95% CI, 42.0-70.0%) of 50 patients achieved clinical benefit, with PFS and OS medians of 3.6 and 16.8 months, respectively. CONCLUSIONS: Gemcitabine and topotecan are active agents in heavily pretreated, platinum- and paclitaxel-resistant EOC patients. Topotecan was more costly to deliver. Although a larger percentage of patients received clinical benefit with topotecan use, this likely reflects physician selection for use of topotecan earlier in the course of disease.