up was conducted. We collected patient, disease, and treatment characteristics and outcomes including OS, progression-free survival (PFS), local control (LC), and freedom from distant metastasis (FDM). Uni-and multivariable survival analyses were performed using Cox regression model. OS was estimated using Kaplan-Meier (KM) test methods. Statistical analysis was performed with JMP version 15.0 software with statistical significance established for p-values < 0.05. Results: Thirty-two patients were treated (1992-2018) with postoperative radiotherapy (RT) including tumor bed/posterior fossa (median dose: 3600 cGy/20 fractions) and craniospinal irradiation (median dose: 2340 cGy/13 fractions) either alone (n Z 10; 31%) or with adjuvant chemotherapy (aCTH: n Z 22; 69%); of whom only 40% were known to complete the full aCTH course. Male patients demonstrated worse OS, PFS, FDM, and LC compared to their female counterparts. Univariable analysis showed sex, tumor location (lateral vs central), and completion of aCTH course to be significantly associated with OS; p<0.05. On multivariable analysis, however, only aCTH completion demonstrated a trend for better OS; HR Z 0.15 (95% CI: 0.02-1.27, p Z 0.08). KM survival analysis revealed superior 5-year OS and PFS in patients who completed aCTH compared to those who received RT alone or did not complete aCTH: 88.9% vs 68.6% vs 40%, p Z 0.03 and 83.3% vs 59.3% vs 42%, p Z 0.04, respectively. Conclusion: Our series demonstrates that completion of aCTH provides a significant OS and PFS advantage for adult medulloblastoma patients. Prospective studies are needed to develop optimal treatment approaches for these patients who have the potential for long term survival.
to improve dose conformity and homogeneity with reduced normal tissue toxicity. The magnitude of benefit on the therapeutic ratio is not clearly defined. This study was designed as a dosimetric study to compare the dose conformity and homogeneity to the PTV and doses received by the organs at risk using 3DCRT, IMRT and VMAT for whole breast irradiation following breast conservation surgery. Materials/Methods: Twenty patients who received whole breast irradiation following breast conservation surgery were included in the study. All the patients received the planned treatment using 3DCRT. The virtual simulation images of these patients were used to generate IMRT and VMAT plans. The Breast CTV, PTV, and organs at risk were contoured according to standard (RTOG) criteria. Dose volume histograms (DVH) were generated for 3DCRT, IMRT, and VMAT plans and various dosimetric parameters such as Homogeneity Index (HI), Conformity Index (CI), dose to heart, both lungs, contralateral (C/L) breast were calculated. One way ANOVA test was used to compare the three groups. The p value less than 0.05 was considered as statistically significant. Results: The HI and CI were significantly better for IMRT and VMAT compared to 3DCRT.There was no significant difference between IMRT and VMAT. The volume of PTV receiving at least 95% of prescribed dose was significantly higher for VMAT compared to 3DCRT. The volume of PTV receiving 107% of the prescribed dose was higher for VMAT and 3DCRT compared to IMRT. The mean heart and lung dose were higher with VMAT and IMRT compared to 3DCRT. There was no significant difference in the volume of heart receiving 30 Gy and volume of ipsilateral lung receiving 20 Gy among the three groups. The mean dose to contra lateral breast and lung were similar for IMRT and 3DCRT, but higher with VMAT.Conclusion: Newer modalities of whole breast irradiation such as IMRT and VMAT appear to provide better PTV dose coverage, homogeneity and conformity that is likely to decrease the skin toxicity and thereby improve cosmesis. However the decrease in doses to the organs at risk reported in other studies could not be demonstrated in this study indicating that such techniques remain an option for a selected group of patients for whom adequate PTV dose coverage could not be achieved with 3DCRT.Purpose/Objective(s): For patients with left-sided breast cancer, radiation treatment to the breast or chest wall can result in high doses to the heart, increasing the risk for cardiac morbidity. The aim of this study was to investigate whether reliable geometric parameters can be identified which predict unfavorable cardiac anatomy and cardiac dose before treatment planning begins. Materials/Methods: Dosimetric analysis was conducted on thirty patients with left-sided breast cancer treated to the breast or chest wall with threedimensional conformal radiation therapy (3D-CRT) using opposed tangents. A prescription dose of 4500 cGy in 25 fractions was used. Whole heart and left ventricle dose volume histograms were analyzed. Five geo...
Purpose/Objective(s): Stereotactic radiosurgery (SRS) is a treatment option for patients with refractory trigeminal neuralgia. We investigated the clinical accuracy of a linear accelerator (Linac)-based noninvasive frameless SRS system in the treatment of trigeminal neuralgia. Materials/Methods: We retrospectively reviewed all patients treated in our institution with SRS for refractory trigeminal neuralgia using Linac-based SRS. Twenty-seven consecutive patients received SRS between August 2011 and November 2015. Twenty-three had at least one postprocedure MRI available. Patients treated prior to December 2012 were treated with a head frame. All patients treated after December 2012 were treated with a noninvasive frameless system. Preprocedure MRI (MRI1) was fused with a simulation CT as part of the treatment planning. The trigeminal nerve was contoured on the preprocedural CT/MRI1 fusion. The postprocedure MRI (MRI2) was fused with the planning CT and MRI1. We contoured the trigeminal nerve as well as the postprocedure enhancing area, if present on MRI2. Using the enhancing area as an in vivo marker for high dose region, we calculated the distance between the planning isocenter and the center of the enhancement. Results: Eight patients were treated with a head frame, and 19 patients were treated with a frameless system. The median follow-up for all patients was 10 months (32.4 months for the patients treated with a head frame, and 13.2 months for the patients treated with a frameless system). Twenty-three patients (85.2%) had at least a temporary or partial response to SRS (8/8 patients treated with a head frame, 15/19 patients treated with a frameless system). Fourteen patients (60.9% with available postprocedure MRI) developed contrast enhancement on postprocedure MRI (71.4% patients treated with a head frame, 50% patients treated with a frameless system). The distance between the planning isocenter and the center of the enhancement was 1.3AE0.5 mm (1.9AE0.4 mm for the head frame system, and 1.1AE0.3 mm for the frameless system). The enhancing area received a mean dose of 75.7 Gy. Conclusion: Linac based frameless SRS system can provide safe and effective treatment for patients with trigeminal neuralgia.
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