Hypoglossal nerve delineation in nasopharyngeal carcinoma patients may reduce the radiation dose and damage to the nerve.

This study aims to establish a delineation guideline for the contouring of the hypoglossal nerve by dividing the nerve into different segments, and to test the possibility of a radiation dose reduction to the hypoglossal nerve in NPC patients receiving radiotherapy. Twenty NPC patients were selected arbitrarily. The hypoglossal nerves were delineated using anatomic landmarks and divided into the cisternal, intracanalicular, carotid, and transverse segments. The tumor coverage by radiation and dose-volume parameters of the nerve with and without various dose constraints to the hypoglossal nerve were compared. The hypoglossal nerve, which is invisible on CT images, can be delineated accurately with the assistance of several anatomic landmarks. Without a dose constraint to the hypoglossal nerve, the carotid space, intracanalicular, and transverse segments had high radiation dose-volumes. The dose-volume to the nerve, however, can be reduced when the nerve was defined and a dose constraint was given. The delineation of the hypoglossal nerve with its different segments is feasible. The carotid space, intracanalicular, and transverse segments received the highest dose, where the nerve damage was most likely located. The dose to the nerve can be reduced to less than 70 Gy using the intensity-modulated radiotherapy technique.

Non-invasive high frequency oscillatory ventilation inhibiting respiratory motion in healthy volunteers.

Precision radiotherapy needs to manage organ movements to prevent critical organ injury. The purpose of this study is to examine the feasibility of motion control of the lung by suppressing respiratory motion. The non-invasive high frequency oscillatory ventilation (NIHFOV) is a technique commonly used in the protection of lung for patients with acute lung disease. By using a very high respiratory frequency and a low tidal volume, NIHFOV allows gas exchange, maintains a constant mean airway pressure and minimizes the respiratory movements. We tested healthy volunteers NIHFOV to explore the optimal operational parameter setting and the best possible motion suppression achievable. This study was conducted with the approval of Institutional Review Boards of the Wuwei Cancer hospital (approval number: 2021-39) and carried out in accordance with Declaration of Helsinki. The study comprises two parts. Twenty three healthy volunteers participated in the first part of the study. They had 7 sessions of training with the NIHFOV. The duration of uninterrupted, continuous breathing under the NIHFOV and the optimal operational machine settings were defined. Eight healthy volunteers took part in the second part of the study and underwent 4-dimensional CT (4DCT) scanning with and without NIHFOV. Their respiratory waveform under free breathing (FB) and NIHFOV were recorded. The maximum range of motion of the diaphragm from the two scannings was compared, and the variation of bilateral lung volume was obtained to evaluate the impact of NIHFOV technique on lung volume. The following data were collected: comfort score, transcutaneous partial pressure of oxygen (PtcO2), transcutaneous partial pressure of carbon dioxide (PtcCO2), and pulse rate. Data with and without NIHFOV were compared to evaluate its safety, physiological impacts and effect of lung movement suppression. All the volunteers completed the training sessions eventlessly, demonstrating a good tolerability of the procedure. The median NIHFOV-on time was 32 min (22-45 min), and the maximum range of motion in the cephalic-caudal direction was significantly reduced on NIHFOV compared with FB (1.8 ± 0.8 cm vs 0.3 ± 0.1 cm, t = - 3.650, P = 0.003); the median range of motion was only 0.3 ± 0.1 cm on NIHFOV with a good reproducibility. The variation coefficient under NIHFOV of the right lung volume was 2.4% and the left lung volume was 9.2%. The PtcO2 and PtcCO2 were constantly monitored during NIHFOV. The medium PtcCO2 under NIHFOV increased lightly by 4.1 mmHg (interquartile range [IQR], 4-6 mmHg) compared with FB (t = 17.676, P < 0.001). No hypercapnia was found, PtcO2 increased significantly in all volunteers during NIHFOV (t = 25.453, P < 0.001). There was no significant difference in pulse rate between the two data sets (t = 1.257, P = 0.233). NIHFOV is easy to master in healthy volunteers to minimize respiratory movement with good tolerability and reproducibility. It is a feasible approach for lung motion control and could potentially be applied in accurate radiotherapy including carbon-ion radiotherapy through suppression of respiratory movement.

Does post-operative radiotherapy improve the treatment outcomes of intracranial hemangiopericytoma? A retrospective study.

BACKGROUND: Intracranial hemangiopericytoma is a rare disease and surgery is the mainstay treatment. Although postoperative adjuvant radiotherapy is often used, there are no reports comparing different radiotherapy techniques. The purpose of this study is to analyze the impact of post-operative radiotherapy and different radiotherapy technique on the results in patients with intracranial hemangiopericytoma (HPC). METHODS: We retrospectively reviewed 66 intracranial HPC patients treated between 1999 and 2019 including 29 with surgery followed by radiotherapy (11 with intensity-modulated radiotherapy (IMRT) and 18 with stereotactic radiosurgery (SRS)) and 37 with surgery alone. Chi-square test was used to compare the clinical characteristic between the groups. The Kaplan-Meier method was used to analyze overall survival (OS) and recurrence-free survival (RFS). Multivariate Cox proportional hazards models were used to examine prognostic factors of survival. We also underwent a matched-pair analysis by using the propensity score method. RESULTS: The crude local control rates were 58.6% in the surgery plus post-operative radiotherapy group (PORT) and 67.6% in the surgery alone group (p = 0.453). In the subgroup analysis of the PORT patients, local controls were 72.7% in the IMRT group and 50% in the SRS group (p = 0.228). The median OS in the PORT and surgery groups were 122 months and 98 months, respectively (p = 0.169). The median RFS was 96 months in the PORT group and 72 months in the surgery alone group (p = 0.714). Regarding radiotherapy technique, the median OS and RFS of the SRS group were not significantly different from those in the IMRT group (p = 0.256, 0.960). The median RFS were 112 and 72 months for pathology grade II and III patients, respectively (p = 0.001). Propensity score matching did not change the observed results. CONCLUSION: In this retrospective analysis, PORT did not improve the local control rates nor the survivals. The local control rates after IMRT and SRS were similar even though the IMRT technique had a much higher biological dose compared with the SRS technique.

Image-based diagnosis of residual or recurrent nasopharyngeal carcinoma may be a phantom tumor phenomenon.

ABSTRACT: Some nasopharyngeal carcinoma (NPC) patients may present convincing radiological evidence mimicking residual or recurrent tumor after radiotherapy. However, by means of biopsies and long term follow-up, the radiologically diagnosed residuals/recurrences are not always what they appear to be. We report our experience on this "phantom tumor" phenomenon. This may help to avoid the unnecessary and devastating re-irradiation subsequent to the incorrect diagnosis.In this longitudinal cohort study, we collected 19 patients of image-based diagnosis of residual/recurrent NPC during the period from Feb, 2010 to Nov. 2016, and then observed them until June, 2019. They were subsequently confirmed to have no residual/recurrent lesions by histological or clinical measures. Image findings and pathological features were analyzed.Six patients showed residual tumors after completion of radiotherapy and 13 were radiologically diagnosed to have recurrences based on magnetic resonance imaging (MRI) criteria 6 to 206 months after radiotherapy. There were 3 types of image patterns: extensive recurrent skull base lesions (10/19); a persistent or residual primary lesion (3/19); lesions both in the nasopharynx and skull base (6/19). Fourteen patients had biopsy of the lesions. The histological diagnoses included necrosis/ inflammation in 10 (52.7%), granulation tissue with inflammation in 2, and reactive epithelial cell in 1. Five patients had no pathological proof and were judged to have no real recurrence/residual tumor based on the absence of detectable plasma EB virus DNA and subjective judgment. These 5 patients have remained well after an interval of 38-121 months without anti-cancer treatments.Image-based diagnosis of residual or recurrent nasopharyngeal carcinoma may be unreliable. False positivity, the "phantom tumor phenomenon", is not uncommon in post-radiotherapy MRI. This is particularly true if the images show extensive skull base involvement at 5 years or more after completion of radiotherapy. MRI findings compatible with NPC features must be treated as a real threat until proved otherwise. However, the balance between under- and over-diagnosis must be carefully sought. Without a pathological confirmation, the diagnosis of residual or recurrent NPC must be made taking into account physical examination results, endoscopic findings and Epstein-Barr virus viral load. A subjective medical judgment is needed based on clinical and laboratory data and the unique anatomic complexities of the nasopharynx.

Heart-sparing effect of postmastectomy radiotherapy for breast cancer patients: A dosimetric study of cardiac substructures.

We investigated to what extent can the dose-volumes of the coronary artery and the cardiac substructures be reduced by using IMRT technique in left-sided breast cancer patients. We chose 40 pN2M0 patients treated with postmastectomy IMRT. The original treatment plans were retrieved and the (internal mammary nodes) IMNs and cardiac substructure delineations were added. Three sets of dose-volume parameters including the original plans without internal mammary irradiation (IMNI), the plans with IMNI, and the plans with dose constraints to the heart, were derived. In left-sided patients, when IMNI was included, the V30 for right ventricle (RV), left ventricle (LV), pulmonic valve (PV), and left anterior descending artery (LADA) were 56.37% ± 7.9%, 25.3% ± 7.3%, 48.3% ± 6.3%, and 69.7% ± 6.4%, respectively. Of the 4 main coronary arteries, LADA had the highest dose followed by the left main coronary artery (LMCA). LADA had a V40 of 62% ± 9.7% vs 13.5% ± 3.5%, and a V50 of 27.5% ± 4.7% vs 0, with and without IMNI. For the right-sided patients, the V30s for all the heart substructures were 0 with or without IMNI. When we set a dose constraint of V40 < 10% for the LADA in the left-sided patients, the PTV volumes covered by 50 Gy decreased by only 1%. IMNI increased the V30 of the right and left ventricle and significantly increased the V40 and V50 to the LADA of left-sided breast cancer patients. IMRT markedly reduces the dose to the main coronary arteries and the right and left ventricle.

An Empirical Model for Describing the Small Field Penumbra in Radiation Therapy.

PURPOSE: We developed a mathematic empirical model for describing the small field penumbra in order to analyze the potential dose perturbation caused by overlapping field to avoid the dose calculation errors in linear accelerator-based radiosurgery. MATERIALS AND METHODS: A ball phantom was fabricated for measuring penumbra at 4 different gantry angles in the coplanar plane. A least square root estimation (LSRE) Model was created to fit the measured penumbra dose profile and to predict the penumbra dose profile at any gantry angles. The Sum of Squared Errors (SSE) was used for finding the parameters n and t for the best fitting of the LSRE model. Geometric and mathematical methods were used to derive the model parameters. RESULTS: The results showed that the larger the gantry angle of the field, the more the expansion of the penumbra dose profile. The least square root estimation model for describing small field penumbra is as follows: Penumbra D s = T · 1 / 2 · 1 - s / n + s 2 + t where Penumbra D(s) denotes the dose profile D(s) at the penumbra region, T is the penumbra height (usually in scalar 100), n is the parameter for curvature, s = x - W d /2 (x and s are the values in cm on x-axis), and t is the radiation transmission of the collimator. Geometric analysis establishes the correlation between the penetration depth of the exposure and its effect on the penumbra region in ball phantom. The penumbra caused by an exposure at any arbitrary angles can be geometrically derived by using a one-variable quadratic equation. CONCLUSION: The dose distribution in penumbra region of small field can be created by the LSRE model and the potential overdosage or underdosage owing to overlapping field perturbation can be estimated.

Treatment outcomes with whole-field versus split-field intensity-modulated radiotherapy for patients with nasopharyngeal carcinoma.

BACKGROUND: The purpose of this study was to present our comparison of the clinical outcome of patients with nasopharyngeal carcinoma (NPC) treated with whole-field intensity-modulated radiotherapy (whole-field-IMRT) or split-field-IMRT. METHODS: We retrospectively studied 388 patients with M0 NPC. The median lower neck doses were 50 Gy in 1.35 Gy/fractions for the 240 whole-field-IMRT patients, and 50.4 Gy in 1.8 to 2.0 Gy/fractions for the 148 split-field-IMRT patients. RESULTS: The IMRT technique did not affect the overall survival (OS; P = .077) and locoregional control (P = .231) rates. However, the split-field-IMRT group had more locoregional recurrences at the whole neck (P = .005) but not at the nasopharynx (P = .968) or the lower neck (P = .485). The patients treated with split-field-IMRT (43.2%) had more grade III neck fibrosis than the patients who received whole-field-IMRT (18.3%; P < .001). Only 1 patient had temporal lobe necrosis in our study. CONCLUSION: Our study shows that whole-field-IMRT using a lower dose/fraction for the lower neck results in at least comparable locoregional control and less fibrosis compared to conventional fraction with split-field-IMRT.

Association between nasopharyngeal carcinoma and risk of optic neuropathy: A population-based cohort study.

BACKGROUND: The purpose of this study was to assess the predictive factors of optic neuropathy among patients with nasopharyngeal carcinoma (NPC). METHODS: The analysis included 16 297 patients with NPC and 65 187 controls. Each patient with NPC was randomly frequency-matched with 4 individuals without NPC by age, sex, and index year. Cox proportional hazard models were applied to measure the hazard ratios (HRs) and 95% confidence intervals (CIs) of optic neuropathy development associated with NPC. RESULTS: The risk of optic neuropathy was significantly higher in the NPC cohort (adjusted HR [aHR] 3.42; 95% CI 2.85-4.09; P < .001). Independent risk factors for optic neuropathy among patients with NPC included stroke (aHR 1.7; 95% CI 1.07-2.7; P = .03) and receipt of chemotherapy (aHR 1.55; 95% CI 1.17-2.06; P = .002). CONCLUSION: The risk of optic neuropathy was significantly higher in patients with NPC than in the general population.

Dose escalation via brachytherapy boost for nasopharyngeal carcinoma in the era of intensity-modulated radiation therapy and combined chemotherapy.

To investigate if dose escalation using intracavitary brachytherapy (ICBT) improves local control for nasopharyngeal carcinoma (NPC) in the era of intensity-modulated radiation therapy (IMRT) and concurrent chemoradiation treatment (CCRT). We retrospectively analyzed 232 patients with Stage T1-3 N0-3 M0 NPC who underwent definitive IMRT with or without additional ICBT boost between 2002 and 2013. For most of the 124 patients who had ICBT boost, the additional brachytherapy was given as 6 Gy in 2 fractions completed within 1 week after IMRT of 70 Gy. CCRT with or without adjuvant chemotherapy was used for 176 patients, including 88 with and 88 without ICBT boost, respectively. The mean follow-up time was 63.1 months. The 5-year overall survival and local control rates were 81.5% and 91.5%, respectively. ICBT was not associated with local control prediction (P = 0.228). However, in a subgroup analysis, 75 T1 patients with ICBT boost had significantly better local control than the other 71 T1 patients without ICBT boost (98.1% vs 85.9%, P = 0.020), despite having fewer patients who had undergone chemotherapy (60.0% vs 76.1%, P = 0.038). Multivariate analysis showed that both ICBT (P = 0.029) and chemotherapy (P = 0.047) influenced local control for T1 patients. Our study demonstrated that dose escalation with ICBT can improve local control of the primary tumor for NPC patients with T1 disease treated with IMRT, even without chemotherapy.

Comparison Between Child-Turcotte-Pugh and Albumin-Bilirubin Scores in Assessing the Prognosis of Hepatocellular Carcinoma After Stereotactic Ablative Radiation Therapy.

PURPOSE: To evaluate the prognostic performance of the Child-Turcotte-Pugh (CTP) score and the albumin-bilirubin (ALBI) score in hepatocellular carcinoma (HCC) patients treated using stereotactic ablative radiation therapy (SABR). METHODS AND MATERIALS: This retrospective study evaluated the data of patients with HCC who underwent SABR between December 2007 and June 2015. We collected pretreatment CTP and ALBI scores and analyzed their correlation with survival and liver toxicity. RESULTS: This study included 152 HCC patients: 78.3% of CTP class A and 21.7% of CTP class B. The median ALBI score was -2.49 (range, -3.67 to -0.84) with 39.5% of grade 1, 56.6% of grade 2, and 3.9% of grade 3. The CTP classification and ALBI grade were significantly associated with overall survival (P<.001). Albumin-bilirubin grade (1 vs 2) had a trend to stratify CTP class A patients into 2 risk groups of mortality (P=.061). Combined CTP class and ALBI score could predict development of radiation-induced liver disease (2.4% in CTP A-ALBI < -2.76, 15.1% in CTP A-ALBI ≥ -2.76, and 25.8% in CTP B). CONCLUSION: Albumin-bilirubin score is a potential predictor for both survival and liver toxicity. Complementary use of CTP and ALBI score could predict the risk of post-SABR liver toxicity. Further prospective studies are necessary before use of the ALBI score can become part of daily practice.

Dose distribution characteristic study of the Rotating Gamma Knife (RGK) by using the geometry analytic method.

The purpose of this study was to realize the processing of dose distribution of RGK at the treatment isocenter at any gantry rotational angle by using an analytic geometry method to avoid inadequate arc therapy angles when implementing the treatment plan. Gaf chromic film was used for dose evaluation. A calibration curve was first obtained using linear accelerator irradiation. The 50% dose relative to the central axis at fixed gantry angles at the x-, y- and z-axes was obtained using Gaf chromic film and was compared to the analytic geometry method. The full width half maximum (FWHM) on the x-, y- and z-axes was predicted for the RGK dose distribution characteristic analysis. The FWHM on the x-, y-, and z-axes varies with different gantry and rotational plate angles. The most dramatic intersection variation appeared at a static gantry angle of 25°. The ratio of the FWHM of the y- and z-axes to that of the x-axis was up to 9 and 10. The geometric analytic method can be used for an accurate analysis of dose distribution in RGK replacing the actual film exposure experiment. It is essential to select the best arc irradiation angle to prescribe the dose to avoid excess irradiation of normal tissue. The geometric method used in this study can also be applied for rotational arc therapy dose analysis such as tomotherapy, linear-based stereotactic radiotherapy, or volume matrices arc therapy.

Survival and prognostic factors for patients with advanced hepatocellular carcinoma after stereotactic ablative radiotherapy.

OBJECTIVE: To evaluate the survival outcomes and prognostic factors of patients with advanced hepatocellular carcinoma (HCC) who underwent stereotactic ablative radiotherapy (SABR). METHODS: This retrospective study evaluated patients with advanced HCC who underwent SABR between December 2007 and July 2015. All patients had Barcelona Clinic Liver Cancer stage C disease and Child-Turcotte-Pugh (CTP) class A-B function. In-field control (IFC), overall survival (OS), prognostic factors, and toxicity were evaluated. RESULTS: In this study of 89 patients, the 3-year IFC rate was 78.1%, and the 1-year and 3-year OS rates were 45.9% and 24.3%, respectively. The multivariate analysis revealed that CTP class, the presence of main portal vein tumor thrombosis, and the presence of extrahepatic spread were independent predictors of OS. The expected median OS values among patients with ≥2, 1, and 0 predictors were 4.2, 8.6, and 26.4 months, respectively (p <0.001). CONCLUSIONS: SABR may be useful for patients with advanced HCC, and patient selection could be based on the CTP classification, main portal vein tumor thrombosis, and extrahepatic spread.

A specially designed domed-cones template for needles (seeds) fixation and incline insertion in prostate implant brachytherapy.

The construction of a conventional prostate needle (seeds) implant template restricts needles tilting or incline insertion when it is necessary to approach a seminal vesicle or to avoid the obstruction of symphysis pubis. To overcome the disadvantages of conventional templates, we developed a special template for guiding needles incline insertion and fixation for prostate needle implant. Phantom needles implantation was performed. Two acrylic boards, each 7.5 cm in width by 7.5 cm in length and 0.5 cm thickness, were drilled with a set of domed holes and cones with embedded template ball inside this combination to provide firm grip and fixation in prostate needle implantation. The specially designed domed-cones combination acrylic board provides a needle of up to 60° rotation flexibility application. Some areas that could not be covered in a conventional parallel needle holes template could now be covered by using this new template. The covering index of prostate radiation dosage is up to 84.5%. The specially designed domed-cones acrylic board combination provides not only a reliable means of needle fixation and rotational function, but also a superior dose distribution in the anterior portion of the prostate and good coverage of a seminal vesicle. This special template is a feasible design for prostate needles or seeds implant brachytherapy.

Temporal Evolution of Parotid Volume and Parotid Apparent Diffusion Coefficient in Nasopharyngeal Carcinoma Patients Treated by Intensity-Modulated Radiotherapy Investigated by Magnetic Resonance Imaging: A Pilot Study.

PURPOSE: To concurrently quantify the radiation-induced changes and temporal evolutions of parotid volume and parotid apparent diffusion coefficient (ADC) in nasopharyngeal carcinoma (NPC) patients treated by intensity-modulated radiotherapy by using magnetic resonance imaging (MRI). MATERIALS AND METHODS: A total of 11 NPC patients (9 men and 2 women; 48.7 ± 11.7 years, 22 parotid glands) were enrolled. Radiation dose, parotid sparing volume, severity of xerostomia, and radiation-to-MR interval (RMI) was recorded. MRI studies were acquired four times, including one before and three after radiotherapy. The parotid volume and the parotid ADC were measured. Statistical analysis was performed using SPSS and MedCalc. Bonferroni correction was applied for multiple comparisons. A P value less than 0.05 was considered as statistically significant. RESULTS: The parotid volume was 26.2 ± 8.0 cm(3) before radiotherapy. The parotid ADC was 0.8 ± 0.15 × 10(-3) mm(2)/sec before radiotherapy. The parotid glands received a radiation dose of 28.7 ± 4.1 Gy and a PSV of 44.1 ± 12.6%. The parotid volume was significantly smaller at MR stage 1 and stage 2 as compared to pre-RT stage (P < .005). The volume reduction ratio was 31.2 ± 13.0%, 26.1 ± 13.5%, and 17.1 ± 16.6% at stage 1, 2, and 3, respectively. The parotid ADC was significantly higher at all post-RT stages as compared to pre-RT stage reciprocally (P < .005 at stage 1 and 2, P < .05 at stage 3). The ADC increase ratio was 35.7 ± 17.4%, 27.0 ± 12.8%, and 20.2 ± 16.6% at stage 1, 2, and 3, respectively. The parotid ADC was negatively correlated to the parotid volume (R = -0.509; P < .001). The parotid ADC was positively associated with the radiation dose significantly (R(2) = 0.212; P = .0001) and was negatively associated with RMI significantly (R(2) = 0.203; P = .00096) significantly. Multiple regression analysis further showed that the post-RT parotid ADC was related to the radiation dose and RMI significantly (R(2) = 0.3580; P < .0001). At MR stage 3, the parotid volume was negatively associated with the dry mouth grade significantly (R(2) = 0.473; P < .0001), while the parotid ADC was positively associated with the dry mouth grade significantly (R(2) = 0.288; P = .015). CONCLUSION: Our pilot study successfully demonstrates the concurrent changes and temporal evolution of parotid volume and parotid ADC quantitatively in NPC patients treated by IMRT. Our results suggest that the reduction of parotid volume and increase of parotid ADC are dominated by the effect of acinar loss rather than edema at early to intermediate phases and the following recovery of parotid volume and ADC toward the baseline values might reflect the acinar regeneration of parotid glands.

Comparing treatment plan in all locations of esophageal cancer: volumetric modulated arc therapy versus intensity-modulated radiotherapy.

The aim of this study was to compare treatment plans of volumetric modulated arc therapy (VMAT) with intensity-modulated radiotherapy (IMRT) for all esophageal cancer (EC) tumor locations.This retrospective study from July 2009 to June 2014 included 20 patients with EC who received definitive concurrent chemoradiotherapy with radiation doses >50.4 Gy. Version 9.2 of Pinnacle with SmartArc was used for treatment planning. Dosimetric quality was evaluated based on doses to several organs at risk, including the spinal cord, heart, and lung, over the same coverage of gross tumor volume.In upper thoracic EC, the IMRT treatment plan had a lower lung mean dose (P = 0.0126) and lung V5 (P = 0.0037) compared with VMAT; both techniques had similar coverage of the planning target volumes (PTVs) (P = 0.3575). In middle thoracic EC, a lower lung mean dose (P = 0.0010) and V5 (P = 0.0145), but higher lung V20 (P = 0.0034), spinal cord Dmax (P = 0.0262), and heart mean dose (P = 0.0054), were observed for IMRT compared with VMAT; IMRT provided better PTV coverage. Patients with lower thoracic ECs had a lower lung mean dose (P = 0.0469) and V5 (P = 0.0039), but higher spinal cord Dmax (P = 0.0301) and heart mean dose (P = 0.0020), with IMRT compared with VMAT. PTV coverage was similar (P = 0.0858) for the 2 techniques.IMRT provided a lower mean dose and lung V5 in upper thoracic EC compared with VMAT, but exhibited different advantages and disadvantages in patients with middle or lower thoracic ECs. Thus, choosing different techniques for different EC locations is warranted.

Comparing outcomes of stereotactic body radiotherapy with intensity-modulated radiotherapy for patients with locally advanced unresectable pancreatic cancer.

OBJECTIVES: Survival in patients with locally advanced unresectable pancreatic cancer (LAUPC) is poor, and local recurrence continues to be a major problem in the management of this disease. Radiotherapy (RT) using different RT techniques, including intensity-modulated radiotherapy (IMRT) and stereotactic body radiation therapy (SBRT), may lead to different clinical outcomes for patients with LAUPC. Here, we compared SBRT with IMRT for patients with LAUPC with respect to survival rate, local control (LC) rate, and toxicity-related dose distribution. MATERIALS AND METHODS: This retrospective study from March 2007 to March 2011 included 41 patients with LAUPC who were divided into two groups, with 20 patients receiving SBRT and 21 patients receiving IMRT. The median follow-up time was 16 months. RESULTS: For the IMRT and SBRT groups, the median survival times were 13 and 20 months, and 1-year overall survival (OS) rates were 70.7 and 80.0%, respectively. There was no difference in OS between the two RT techniques. RT with SBRT showed significantly better local disease-free survival than IMRT for patients with LAUPC. Tobacco use had a borderline effect on LC. Thus, further statistical analysis showed that patients who used tobacco had better LC after receiving SBRT than IMRT. CONCLUSION: SBRT improved LC for LAUPC patients and had similar radiation toxicity compared with IMRT. Further study is required to define the effects of administered radiation dose and fractionation, as well as to further expand the sample size, to use a prospective study, and to observe the long-term efficacy of these techniques.

Subsequent risk of nasopharyngeal carcinoma among patients with allergic rhinitis: a nationwide population-based cohort study.

BACKGROUND: The purpose of this study was to examine the risk of nasopharyngeal carcinoma (NPC) after a diagnosis of allergic rhinitis. METHODS: We identified 67,532 patients with allergic rhinitis (allergic rhinitis cohort) and a 135,064 control cohort with the same mean age and sex ratio by using a Taiwan Longitudinal Health Insurance Database (LHID) sample from 2000 to 2005. RESULTS: After adjusting for the possible confounding factors of the study, the allergic rhinitis cohort had a 2.33-fold higher risk of developing NPC than did the comparison cohort. The frequency of allergic rhinitis visits was correlated with the risk of subsequent NPC. Patients with 4 or more allergic rhinitis visits per year were significantly associated with increasingly developing NPC risk. CONCLUSION: Patients with allergic rhinitis might be associated with subsequent NPC in Taiwan. Those who had repeated visits for allergic rhinitis had even higher risk for NPC. Physicians should be aware of the link when assessing patients with allergic rhinitis.

Repeated stereotactic ablative radiotherapy using CyberKnife for patients with hepatocellular carcinoma.

BACKGROUND AND AIM: This study aimed to evaluate the outcomes and toxicities of repeated stereotactic ablative radiotherapy (SABR) in hepatocellular carcinoma (HCC). METHODS: Fourteen HCC patients with local recurrence (18 lesions) after liver SABR received repeated radiotherapy with SABR using CyberKnife. No patients experienced radiation-induced liver disease after the first SABR course. The median first SABR dose was 41 Gy (range, 34-60 Gy); the median second SABR dose, 40 Gy (range, 25-50 Gy); and the median interval, 12.9 months. Local recurrence was divided into in-field recurrence and out-field recurrence. RESULTS: Objective responses were observed in 11 tumors (61.1%), including five tumors (27.8%) with complete responses. Intrahepatic out-field failure was the main cause of treatment failure (7 of 14 patients). In-field failure had developed in 1 of 18 tumors (5.6%), resulting in a 2-year in-field failure-free rate of 88.2%. The median time to progression was 14.0 months, with 1- and 2-year progression-free survival rates of 68.6% and 42.9%, respectively. One- and two-year overall survival rates were 76% and 59.1%, respectively. Of the 14 patients, one developed radiation-induced liver disease and three showed progression of the Child-Turcotte-Pugh class after the second SABR course. Other toxicities were generally mild and tolerable. CONCLUSION: Repeated SABR in selected HCC patients is feasible with acceptable toxicity.

Novel application of stereotactic ablative radiotherapy using CyberKnife® for early-stage renal cell carcinoma in patients with pre-existing chronic kidney disease: Initial clinical experiences.

The treatment of renal cell carcinoma (RCC) in patients diagnosed with chronic kidney disease (CKD) requires particular care in order to preserve the remaining renal function. The present study aimed to investigate the potential of a novel nephron-sparing treatment, which is capable of targeting tumors embedded deep within tissues. The present study analyzed three patients, with pre-existing CKD and multiple comorbidities, who were successfully treated for stage I RCC using the CyberKnife® stereotactic ablative radiotherapy (SABR) system. The total prescribed dose was 40 Gy in five fractions administered over five consecutive days. Treatment efficiency was determined using computed tomography scans of the tumors and periodic measurements of the glomerular filtration rate over a period of 12-40 months. Local control, defined as a radiologically stable condition, was achieved in all patients. Lung metastasis was observed in one patient nine months after SABR; however, the side-effects were generally mild and self-limiting. One patient developed renal failure 26 months after SABR, while the severity of CKD was only marginally altered in the other two patients and renal failure did not occur. In conclusion, in the present study, SABR with CyberKnife® was observed to be well tolerated in the patients, with an acceptable acute toxicity effect. Therefore, it may represent a potential therapeutic option for patients with early-stage RCC who have previously been diagnosed with CKD, but for whom other nephron-sparing treatments are contraindicated.

Stereotactic ablative radiotherapy for unresectable hepatocellular carcinoma patients who failed or were unsuitable for transarterial chemoembolization.

BACKGROUND: The role of stereotactic ablative radiotherapy (SABR) in patients with hepatocellular carcinoma (HCC) who are refractory to or unsuitable for transarterial chemoembolization remains unclear. We examined the efficacy and safety of Cyberknife SABR and its effect on survival in this group of HCC patients. MATERIALS AND METHODS: From June 2008 to June 2011, 53 patients with 68 tumors of unresectable HCC were treated using Cyberknife SABR. The tumors measured 1.1-13 cm (median, 4.3 cm). The median prescribed dose was 40 Gy in four to five fractions over 4-5 consecutive working days. RESULTS: The median follow-up period was 13.1 months for all patients and 18.1 months for the living patients. Objective responses were observed in 48 of 67 tumors (71.6%), including 22 tumors (32.8%) with complete responses. The 1- and 2-year in-field failure-free rate was 73.3 and 66.8%, respectively. Out-field intrahepatic recurrence was the main cause of treatment failure (28/52 patients). The median survival time was 20.0 months, and the 1- and 2-year overall survival rate was 70.1 and 45.4%, respectively. Multivariable analysis showed that Eastern Cooperative Oncology Group performance status (≤1 vs. >1) and tumor response (responder vs. nonresponder) were independent prognostic factors for overall survival. Radiation-induced liver disease, including classic and nonclassic types, developed in five patients (9.4%). Other acute toxicities were generally mild and tolerable. CONCLUSION: Our findings supported the feasibility of SABR as a salvage treatment for HCC when transarterial chemoembolization was ineffective or technically unsuitable. Additional efforts to improve the response rate and reduce out-field recurrence are required.