Conformity of LINAC-based stereotactic radiosurgery using dynamic conformal arcs and micro-multileaf collimator.

PURPOSE: To assess the conformity of dynamic conformal arc linear accelerator-based stereotactic radiosurgery and to describe a standardized method of isodose surface (IDS) selection. METHODS AND MATERIALS: In 174 targets, the conformity index (CI) at the prescription IDS used for treatment was calculated as CI = (PIV/PVTV)/(PVTV/TV), where TV is the target volume, PIV (prescription isodose volume) is the total volume encompassed by the prescription IDS, and PVTV is the TV encompassed by the IDS. In addition, a "standardized" prescription IDS (sIDS) was chosen according to the following criteria: 95% of the TV was encompassed by the PIV and 99% of TV was covered by 95% of the prescription dose. The CIs at the sIDS were also calculated. RESULTS: The median CI at the prescription IDS and sIDS was 1.63 and 1.47, respectively (p < 0.001). In 132 of 174 cases, the volume of normal tissue in the PIV was reduced by the prescription to the sIDS compared with the prescription IDS, in 20 cases it remained unchanged, and in 22 cases it was increased. CONCLUSION: The CIs obtained with linear accelerator-based stereotactic radiosurgery are comparable to those previously reported for gamma knife stereotactic radiosurgery. Using a uniform method to select the sIDS, adequate target coverage was usually achievable with prescription to an IDS greater than that chosen by the treating physician (prescription IDS), providing sparing of normal tissue. Thus, the sIDS might aid physicians in identifying a prescription IDS that balances coverage and conformity.

Gorham disease of the mandible: radiographic findings and radiotherapy response.

Gorham disease, a rare condition of unknown etiology, is characterized histologically by bone disintegration and endothelial proliferation. We describe serial imaging findings, the treatment course, and radiotherapy response in a patient with pathologically confirmed Gorham disease involving the right mandible. Progressive mandibular resorption was managed initially with multiple surgical resections and reconstruction, followed by external-beam radiotherapy, which was an effective treatment method in this case. The patient's reconstructed mandible is functional and he is asymptomatic. Our literature review provides further insights regarding the clinical, radiologic, and pathologic behavior of this entity and examines the available treatment strategies.

Descriptive nomograms of adjuvant radiotherapy use and patterns of care analysis for stage I and II endometrial adenocarcinoma: A surveillance, epidemiology, and end results population study.

BACKGROUND: Although endometrial cancer remains the most common gynecologic malignancy in the United States, differing approaches to adjuvant radiotherapy treatment for early disease exist within the medical community because of the lack of a national consensus. METHODS: The authors studied patterns of adjuvant care for stage I and II endometrial adenocarcinoma using a large United States population database. A retrospective analysis was conducted from the Surveillance, Epidemiology, and End Results (SEER) Program of the U.S. National Cancer Institute from 1988 to 2002, and 26,923 women with American Joint Committee on Cancer stage I and II endometrial adenocarcinoma were selected. The following prognostic factors were analyzed: age, race, stage, grade, year of diagnosis, SEER registry location, and use and type of postoperative radiotherapy (RT). Adjuvant RT was coded as none, external-beam RT (EBRT), brachytherapy (BR), or a combination of the 2 (EBRT + BR). RESULTS: Higher tumor grade and stage led to greater use of RT. The odds ratio (OR) for adjuvant RT was 3.4 for stage IB versus stage IA and 51.8 for stage IC/II versus stage IA. The effect of grade depended on stage: for stages IA and IB, the OR was 2.9 for grade 2 versus grade 1 and 11.7 for grade 3/4 versus grade 1; whereas, for stage IC/II, the OR was 1.5 for grade 2 versus grade 1 and 2.0 for grade 3/4 versus grade 1. Within stage I, increasing substage and grade increased the odds of EBRT with or without BR compared with BR alone. Race did not effect the choice of therapy (all P > .1). Geographic location had a significant effect on overall RT use and therapy choice. CONCLUSIONS: To the authors' knowledge, this was the largest patterns of care analysis to date of adjuvant RT in patients with stage I and II endometrial adenocarcinoma. The current study revealed that there is significant diversity in the use of adjuvant RT across the United States, and the results reflected the absence of a national consensus on adjuvant treatment for early-stage disease.