Impact of paraaortic lymphadenectomy for endometrial cancer with positive pelvic lymph nodes: A Korean Radiation Oncology Group study (KROG 13-17).

AIM: We investigated the role of paraaortic lymph node dissection (PALND) in patients with stage IIIC1 endometrial carcinoma after surgery followed by adjuvant radiotherapy (RT) alone or chemoradiotherapy (CTRT). METHODS: We performed a subgroup analysis in 151 patients treated with adjuvant pelvic RT. Paraaortic-recurrence free survival, disease-free survival (DFS) and overall survival (OS) were analyzed. RESULTS: In adjuvant RT alone, PALND was significantly related to reduced risk of paraaortic recurrence (0% vs. 17.1%) and distant metastasis (4.5% vs. 19.5%) compared with the no PALND group. PALND affected 5-year DFS (90.2% vs. 58.9%, p = 0.016) and OS (100% vs. 83.1%, p = 0.022). For the CTRT group, the paraaortic recurrence rate was 19.5% for the no PALND group and 12.8% for the PALND group (p = 0.682). Of patients who underwent PALND in the CTRT group, less extensive PALND was significantly related to increased paraaortic recurrence (≤10 vs. >10 dissected LNs, 17.1% vs. 0%). In the no PALND group (n = 82), 5-year paraaortic-recurrence free survival was 79.4% for the CTRT group and 76.2% for the RT alone group (p = 0.941). In multivariate analysis, PALND was significantly associated with reduced risk of disease-specific death (HR, 0.50; 95% CI, 0.26-0.96; p = 0.037). CONCLUSION: PALND provided excellent paraaortic control and improved outcome in stage IIIC1 endometrial cancer with favorable tumor features treated with adjuvant RT alone. Less extensive PALND was associated with significantly increased paraaortic recurrence in patients with advanced tumor features treated with adjuvant CTRT. Combined CTRT did not affect disease control in the paraaortic region compared with RT alone.

The effectiveness of gadolinium MRI to improve target delineation for radiotherapy in hepatocellular carcinoma: a comparative study of rigid image registration techniques.

To achieve consistent target delineation in radiotherapy for hepatocellular carcinoma (HCC), image registration between simulation CT and diagnostic MRI was explored. Twenty patients with advanced HCC were included. The median interval between MRI and CT was 11 days. CT was obtained with shallow free breathing and MRI at exhale phase. On each CT and MRI, the liver and the gross target volume (GTV) were drawn. A rigid image registration was taken according to point information of vascular bifurcation (Method[A]) and pixel information of volume of interest only including the periphery of the liver (Method[B]) and manually drawn liver (Method[C]). In nine cases with an indefinite GTV on CT, a virtual sphere was generated at the epicenter of the GTV. The GTV from CT (VGTV[CT]) and MRI (VGTV[MR]) and the expanded GTV from MRI (V+GTV[MR]) considering geometrical registration error were defined. The underestimation (uncovered V[CT] by V[MR]) and the overestimation (excessive V[MR] by V[CT]) were calculated. Through a paired T-test, the difference between image registration techniques was analyzed. For method[A], the underestimation rates of VGTV[MR] and V+GTV[MR] were 16.4 ± 8.9% and 3.2 ± 3.7%, and the overestimation rates were 16.6 ± 8.7% and 28.4 ± 10.3%, respectively. For VGTV[MR] and V+GTV[MR], the underestimation rates and overestimation rates of method[A] were better than method[C]. The underestimation rates and overestimation rates of the VGTV[MR] were better in method[B] than method[C]. By image registration and additional margin, about 97% of HCC could be covered. Method[A] or method[B] could be recommended according to physician preference.

Interfractional variability in intensity-modulated radiotherapy of prostate cancer with or without thermoplastic pelvic immobilization.

PURPOSE: To determine the variability of patient positioning errors associated with intensity-modulated radiotherapy (IMRT) for prostate cancer and to assess the impact of thermoplastic pelvic immobilization on these errors using kilovoltage (kV) cone-beam computed tomography (CBCT). MATERIALS AND METHODS: From February 2012 to June 2012, the records of 314 IMRT sessions in 19 patients with prostate cancer, performed with or without immobilization at two different facilities in the Korea University Hospital were analyzed. The kV CBCT images were matched to simulation computed tomography (CT) images to determine the simulation-to-treatment variability. The shifts along the x (lateral)-, y (longitudinal)- and z (vertical)-axes were measured, as was the shift in the three dimensional (3D) vector. RESULTS: The measured systematic errors in the immobilized group during treatment were 0.46 ± 1.75 mm along the x-axis, - 0.35 ± 3.83 mm along the y-axis, 0.20 ± 2.75 mm along the z-axis and 4.05 ± 3.02 mm in the 3D vector. Those of nonimmobilized group were - 1.45 ± 7.50 mm along the x-axis, 1.89 ± 5.07 mm along the y-axis, 0.28 ± 3.81 mm along the z-axis and 8.90 ± 4.79 mm in the 3D vector. The group immobilized with pelvic thermoplastics showed reduced interfractional variability along the x- and y-axes and in the 3D vector compared to the nonimmobilized group (p < 0.05). CONCLUSION: IMRT with thermoplastic pelvic immobilization in patients with prostate cancer appears to be useful in stabilizing interfractional variability during the planned treatment course.

Set-up uncertainty during breast radiotherapy. Image-guided radiotherapy for patients with initial extensive variation.

PURPOSE: The aim of this work was to establish a customized strategy for image-guided radiotherapy during whole breast irradiation. Risk factors associated with extensive errors were assessed. METHODS AND MATERIALS: A series of 176 consecutive breasts in 174 patients were retrospectively assessed. Electronic portal images from 914 medial and 807 lateral directions were reviewed. On the basis of the chest wall, the deviations between the simulation and each treatment were measured. The systematic (Σ) and random error (σ) of population, and the planning target volume (PTV) margin (2 Σ + 0.7σ) were calculated for each direction. Extensive set-up errors were defined as the fraction over the PTV margins in any direction. For extensive set-up errors, χ(2) tests and logistic regression analyses were conducted. RESULTS: The medial and lateral PTV margins for the right-left, superior-inferior, and anterior-posterior axes and the rotation of collimator were 2.6 and 2.4 mm, 4.6 and 4.6 mm, and 3.1 and 3.3 mm and 2.8 and 2.9 ° and cut-off values for extensive errors were 3, 5, and 4 mm and 3 °, respectively. In χ(2) tests, tumor in upper outer quadrant (p = 0.012) and chest wall thickness ≥ 2.0 cm (p = 0.003) for medial portals and age group (p = 0.036) for lateral portals were associated with extensive errors. In multivariate tests, the extensive error on the initial fraction had a high probability of extensive set-up errors in both medial (OR = 4.26, p < 0.001) and lateral portals (OR = 3.07, p < 0.001). CONCLUSION: In terms of the set-up uncertainty during breast irradiation, patients with extensive error in the initial treatment should be closely observed with serial image-guided radiotherapy.

Development of decay energy spectroscopy using low temperature detectors.

We have developed a high-resolution detection technique for measuring the energy and activity of alpha decay events using low-temperature detectors. A small amount of source material containing alpha-emitting radionuclides was enclosed in a 4π metal absorber. The energy of the alpha particles as well as that of the recoiled nuclides, low-energy electrons, and low-energy x-rays and γ-rays was converted into thermal energy of the gold absorber. A metallic magnetic calorimeter serving as a fast and sensitive thermometer was thermally attached to the metal absorber. In the present report, experimental demonstrations of Q spectroscopy were made with a new meander-type magnetic calorimeter. The thermal connection between the temperature sensor and the absorber was established with annealed gold wires. Each alpha decay event in the absorber resulted in a temperature increase of the absorber and the temperature sensor. Using the spectrum measured for a drop of (226)Ra solution in a 4π gold absorber, all of the alpha emitters in the sample were identified with a demonstration of good detector linearity. The resolution of the (226)Ra spectrum showed a 3.3 keV FWHM at its Q value together with an expected gamma escape peak at the energy shifted by its γ-ray energy.

Risk factors related to interfractional variation in whole pelvic irradiation for locally advanced pelvic malignancies.

PURPOSE: The goal of the present study was to demonstrate risk factors affecting the interfractional variation in whole pelvic irradiation. PATIENTS AND METHODS: Daily image acquisitions of 101 patients with locally advanced pelvic malignancy were undertaken using a kilo-voltage orthogonal on-board imager. The baseline deviation (the shift between the initial treatment and each fraction; Value(Base)) and day-to-day variation (the shift between the previous treatment and each fraction; Value(DD)) were measured. The standard deviations (SD) along the x- (right-left), y- (cranial-caudal), and z- (anterior-posterior) axes (SD[x], SD[y], and SD[z], respectively), the 3D vector of the SD (SD[3D]), and the mean of 3D shift (mean[3D]) were calculated in each patient. Various clinical factors, lumbar pelvic balance and rotation, and the shift of 5 consecutive fractions from the initial treatment (Value(5Fx)) were investigated as risk factors. RESULTS: The prone set-up showed a larger mean(Base)[3D] than in the supine position (p =0 .063). A body mass index (BMI) ≥ 30 kg/m(2) resulted in the largest mean(DD)[3D] (p = 0.078) and SD(DD)[3D] (p = 0.058). All the SD(5Fx) along the x-, y-, and z-axes had moderate linear relationships with SD(Base) and SD(DD) (p < 0.001). The SD(5Fx)[3D] also had a moderate linear relationship with the mean(Base)[3D], mean(DD)[3D], SD(Base)[3D], and SD(DD)[3D] (p < 0.001). In multivariate analysis, the SD(5Fx) had the same significant relationship with SD(Base) and SD(DD) (p < 0.001). A BMI ≥ 30 kg/m(2) was associated with the largest SD(DD)[x] (p = 0.003). CONCLUSION: Close surveillance through high-quality and frequent image guidance is recommended for patients with extensive variations of the initial five consecutive fractions or obesity.

Rubella-associated aplastic anemia treated by syngeneic stem cell transplantations.

A 14-year-old boy presented with aplastic anemia 3 months after contracting rubella. Stem cell transplantations from his identical twin were carried out. Successful engraftment occurred only when conditioning therapy was given prior to the infusion of the syngeneic stem cells, supporting an immune mechanism to explain the pathogenesis of virus-associated aplastic anemia.

Successful allogeneic bone marrow transplantation for childhood-onset refractory anemia with ringed sideroblasts.

Refractory anemia with ringed sideroblasts (RARS) is an extremely rare type of myelodysplastic syndrome in children. We describe a 10-year-old boy with RARS presented with pancytopenia. He remained relatively stable with only a few transfusions until age of 20 years, when he underwent an allogeneic bone marrow transplantation (BMT) because of increased transfusion requirements. He remains in complete chimeric state at 20 months posttransplant with normal hematologic parameters. To our knowledge, this is the first description of successful BMT in a patient with childhood-onset RARS. The indication of BMT for this rare disorder in children is discussed.

Fanconi anemia screening by diepoxybutane and mitomicin C tests in Korean children with bone marrow failure syndromes.

Fanconi anemia (FA) is an autosomal recessive disorder of progressive bone marrow failure in patients with congenital malformations. FA is different from acquired aplastic anemia (AA) in terms of the natural course and treatment options. As the frequency of FA is unknown in Korea, we conducted screening tests using DNA clastogenic agents, diepoxybutane (DEB) and mitomicin C (MMC) in southwestern Korea. Forty-three children with AA or other bone marrow failure syndromes and siblings of known FA were evaluated. Six patients with AA (6/24=25.0%) and a 2-month-old patient with myelodysplastic syndrome were found to have increased chromosomal breakage to both DEB and MMC, confirming the diagnosis of FA. No overlap in chromosomal breakage to both agents was found between the FA group and non-FA group. The frequency of FA in this study, much higher than those of previous studies in Korea which did not incorporate the above tests, was similar to that of other countries. DEB and MMC tests were readily feasible and useful in screening FA in patients with AA as well as other bone marrow failure syndromes. A nation-wide screening and registry for FA should be initiated since FA requires different therapeutic and management options from idiopathic AA.

Dynamic canal encroachment during thoracolumbar burst fractures.

In the burst fractures seen clinically, often poor correlation exists between the neurological deficit and the canal encroachment measured on post-trauma radiographic images. The purpose of the present study was to determine whether the dynamic canal encroachment during the trauma is greater than the static canal encroachment posttrauma. We successfully produced burst fractures in nine of 15 fresh human cadaveric thoracolumbar spine specimens (T11-L1). The specimens were incrementally impacted in a high-speed trauma apparatus until fracture occurred. During the trauma, dynamic canal encroachments were measured using three specially designed transducers placed in the canal at the levels of the superior end-plates of the T12 and L1 and the T12/L1 disk. After the trauma, residual static spinal canal encroachments were measured from the radiographs of the specimens that were prepared with 1.6-mm diameter steel balls lining the canal in the midsagittal plane. We found that the average canal diameter was 16.6 +/- 1.3 mm and the static canal encroachment was 18.0% of the canal diameter. The corresponding dynamic canal encroachment was 33.3%. Thus, the dynamic canal encroachment was 85% more than the static measurement. The clinical significance of this study lies in providing awareness to the clinician that the dynamic canal encroachment is significantly greater than the static canal encroachment seen on posttrauma radiographs or computed tomography scans. The finding may also explain the clinical observation of poor correlation between the canal encroachment measured radiographically and the neurological deficit.