Measurement of body composition in response to a short period of overfeeding

Background

Obesity and overweight are increasing in prevalence in developed countries as a result of changing dietary habits and a lack of physical activity. The purpose of the present study was to evaluate the changes in body composition during short-term overfeeding using the three-component model, which is composed of fat mass (FM), total body water (TBW), and fat-free dry solids (FFDS).

Methods

Ten healthy men completed 3 days of overfeeding during which they consumed 1,500 kcal/day more energy than consumed in their normal diets. Body composition was evaluated at three time points: the day before and after their normal diets and the day after the 3-day overfeeding diet.

Results

Before and after their normal diets, there were no significant differences in body weight and composition, but after 3 days of overfeeding, body weight, TBW, and FFDS increased 0.7, 0.7, and 0.2 kg, respectively (P <0.0001). There was no significant difference in FM between the normal and overfeeding diets.

Conclusion

This study suggests that TBW gain contributes to weight gain following a short-term overfeeding.     

Measurement and comparison of head scatter factor for 7 MV unflattened (FFF) and 6 MV flattened photon beam using indigenously designed columnar mini phantom

Aim

To measure and compare the head scatter factor for 7 MV unflattened and 6 MV flattened photon beam using a home-made designed mini phantom.

Background

The head scatter factor (Sc) is one of the important parameters for MU calculation. There are multiple factors that influence the Sc values, like accelerator head, flattening filter, primary and secondary collimators.

Materials and methods

A columnar mini phantom was designed as recommended by AAPM Task Group 74 with high and low atomic number material for measurement of head scatter factors at 10 cm and d_max dose water equivalent thickness.

Results

The Sc values measured with high-Z are higher than the low-Z mini phantoms observed for both 6MV-FB and 7MV-UFB photon energies. Sc values of 7MV-UFB photon beams were smaller than those of the 6MV-FB photon beams (0.6–2.2% (Primus), 0.2–1.4% (Artiste) and 0.6–3.7% (Clinac iX (2300CD))) for field sizes ranging from 10 cm × 10 cm to 40 cm × 40 cm. The SSD had no influence on head scatter for both flattened and unflattened beams. The presence of wedge filters influences the Sc values. The collimator exchange effects showed that the opening of the upper jaw increases Sc irrespective of FF and FFF.

Conclusions

There were significant differences in Sc values measured for 6MV-FB and unflattened 7MV-UFB photon beams over the range of field sizes from 10 cm × 10 cm to 40 cm × 04 cm. Different results were obtained for measurements performed with low-Z and high-Z mini phantoms.     

Dependence of the safe rectum dose on the CTV–PTV margin size and treatment technique

Background

Late rectal injury is a common side effect of external beam radiotherapy for prostate cancer.

Aim

The aim of this study was to evaluate what total dose may be safely delivered for prostate patients for 3DCRT and IMRT techniques and the CTV–PTV margin.

Materials and methods

3DCRT and IMRT plans were prepared for 12 patients. For each patient PTV was defined with CTV–PTV margins of 0.4, 0.6, …, 1.0 cm, and total doses of 70, 72, …, 80 Gy, with 2 Gy dose fraction. NTCP values for the rectum were calculated using the Lyman model. Both techniques were compared in terms of population mean DVH.

Results

Significantly smaller NTCPs for IMRT were obtained. For both techniques diminishing the margin CTV–PTV of 2 mm leads to decreasing the NTCP of about 0.03. For total dose of 80 Gy the NTCP was smaller than 10% for the 4 mm margin only. The QUANTEC dose volume constraints were more frequently fulfilled for the IMRT technique than for the 3DCRT technique.

Conclusions

The IMRT technique is safer for prostate patients than the 3DCRT. If very high total doses are applied the CTV–PTV margin of 0.4 cm and the IMRT technique should be used. If the CTV–PTV margin of 0.6 cm is applied, the NTCP is smaller than 10% for the 3DCRT and IMRT techniques for the total doses smaller than 74 Gy and 78 Gy, respectively.     

Hyperfractionated high-dose rate brachytherapy in the treatment of oral tongue cancer

Background

Low-dose rate brachytherapy is a well established treatment modality of oral cancer. Data about high-dose rate (HDR) brachytherapy are still sparse with various fractionation schedules and heterogeneous results.

Aim

The aim of our retrospective study was to evaluate the results of HDR brachytherapy with doses of 3 Gy twice daily.

Patients and methods

Twenty patients with squamous cell tongue cancer were treated in the years 2001–2009 by exclusive HDR BT 18 × 3 Gy twice daily. The plastic tube technique was used. Median follow up was 47 months (7.8–118) since brachytherapy.

Results

The local and locoregional control was 85% and 68%, respectively. Bone necrosis developed in one case treated without mandibular shielding and soft tissue necrosis in 2 cases.

Conclusion

It can be concluded that HDR brachytherapy with 18 × 3 Gy twice daily is safe with promising local control. The risk of nodal recurrences is substantial.     

Set-up uncertainty during postmastectomy radiotherapy with Segmented Photon Beams Technique

Aim

To verify the reproducibility of patients irradiated after mastectomy on the immobilization system designed and manufactured for our hospital and to compare the Internal Protocol (IP) with the modified-No Action Level Protocol.

Background

Application of forward IMRT techniques requires a good reproducibility of patient positioning. To minimize the set-up error, an effective immobilization system is important.

Materials and methods

The study was performed for two groups of 65 each. In the first group, portal images for anterior field were taken in 1–3 fractions and, subsequently, three times a week. In this group, the mNAL protocol was used. In the second group, the IP was used. The portal images from the anterior field and from the gantry 0 were taken during the 1–3 and 10 fractions. In both groups, image registration was performed off-line. For each group the systematic and random errors and PTV margin were calculated.

Results

In the first group the value of the population systematic errors and random errors were 1.6 ± 1.6 mm for the left–right, and 1.5 ± 1.7 mm for the cranial–caudal directions, respectively, 1.7 ± 1.3 mm, and 1.9 ± 1.3 mm for the second group. The PTV margins for the left–right and cranial–caudal directions were 5.1 and 4.9 mm for the first group and 5.4 and 6.4 mm for the second group.

Conclusions

For patients immobilized with our support device treated according to the mNAL protocol or IP, a good set-up reproducibility was obtained. Implementation of IP limits the number of required images.     

Off-Hour Effect on 3-Month Functional Outcome after Acute Ischemic Stroke: A Prospective Multicenter Registry

Background and Purpose

The time of hospital arrival may have an effect on prognosis of various vascular diseases. We examined whether off-hour admission would affect the 3-month functional outcome in acute ischemic stroke patients admitted to tertiary hospitals.

Methods

We analyzed the ‘off-hour effect’ in consecutive patients with acute ischemic stroke using multi-center prospective stroke registry. Work-hour admission was defined as when the patient arrived at the emergency department between 8 AM and 6 PM from Monday to Friday and between 8 AM and 1 PM on Saturday. Off-hour admission was defined as the rest of the work-hours and statutory holidays. Multivariable logistic regression was used to analyze the association between off-hour admission and 3-month unfavorable functional outcome defined as modified Rankin Scale (mRS) 3–6. Multivariable model included age, sex, risk factors, prehospital delay time, intravenous thrombolysis, stroke subtypes and severity as covariates.

Results

A total of 7075 patients with acute ischemic stroke were included in this analysis: mean age, 67.5 (±13.0) years; male, 58.6%. In multivariable analysis, off-hour admission was not associated with unfavorable functional outcome (OR, 0.89; 95% CI, 0.72–1.09) and mortality (OR, 1.09; 95% CI, 0.77–1.54) at 3 months. Moreover, off-hour admission did not affect a statistically significant shift of 3-month mRS distributions (OR, 0.90; 95% CI, 0.78–1.05).

Conclusions

‘Off-hour’ admission is not associated with an unfavorable 3-month functional outcome in acute ischemic stroke patients admitted to tertiary hospitals in Korea. This finding indicates that the off-hour effects could be overcome with well-organized stroke management strategies.     

Comparison of dosimetric variation between prostate IMRT and VMAT due to patient's weight loss: Patient and phantom study

Aim

This study compared the dosimetric impact between prostate IMRT and VMAT due to patient''s weight loss.

Background

Dosimetric variation due to change of patient''s body contour is difficult to predict in prostate IMRT and VMAT, since a large number of small and irregular segmental fields is used in the delivery.

Materials and methods

Five patients with prostate volumes ranging from 32.0 to 86.5 cm³ and a heterogeneous pelvis phantom were used for prostate IMRT and VMAT plans using the same set of dose–volume constraints. Doses in IMRT and VMAT plans were recalculated with the patient''s and phantom''s body contour reduced by 0.5–2 cm to mimic size reduction. Dose coverage/criteria of the PTV and CTV and critical organs (rectum, bladder and femoral heads) were compared between IMRT and VMAT.

Results

In IMRT plans, increases of the D99% for the PTV and CTV were equal to 4.0 ± 0.1% per cm of reduced depth, which were higher than those in VMAT plans (2.7 ± 0.24% per cm). Moreover, increases of the D30% of the rectum and bladder per reduced depth in IMRT plans (4.0 ± 0.2% per cm and 3.5 ± 0.5% per cm) were higher than those of VMAT (2.2 ± 0.2% per cm and 2.0 ± 0.6% per cm). This was also true for the increase of the D5% for the right femoral head in a patient or phantom with size reduction due to weight loss.

Conclusions

VMAT would be preferred to IMRT in prostate radiotherapy, when a patient has potential to suffer from weight loss during the treatment.     

Air kerma strength characterization of a GZP6 Cobalt-60 brachytherapy source

Background

Task group number 40 (TG-40) of the American Association of Physicists in Medicine (AAPM) has recommended calibration of any brachytherapy source before its clinical use. GZP6 afterloading brachytherapy unit is a ⁶⁰Co high dose rate (HDR) system recently being used in some of the Iranian radiotherapy centers.

Aim

In this study air kerma strength (AKS) of ⁶⁰Co source number three of this unit was estimated by Monte Carlo simulation and in air measurements.

Materials and methods

Simulation was performed by employing the MCNP-4C Monte Carlo code. Self-absorption of the source core and its capsule were taken into account when calculating air kerma strength. In-air measurements were performed according to the multiple distance method; where a specially designed jig and a 0.6 cm³ Farmer type ionization chamber were used for the measurements. Monte Carlo simulation, in air measurement and GZP6 treatment planning results were compared for primary air kerma strength (as for November 8th 2005).

Results

Monte Carlo calculated and in air measured air kerma strength were respectively equal to 17240.01 μGym² h⁻¹ and 16991.83 μGym² h⁻¹. The value provided by the GZP6 treatment planning system (TPS) was “15355 μGym² h⁻¹”.

Conclusion

The calculated and measured AKS values are in good agreement. Calculated-TPS and measured-TPS AKS values are also in agreement within the uncertainties related to our calculation, measurements and those certified by the GZP6 manufacturer. Considering the uncertainties, the TPS value for AKS is validated by our calculations and measurements, however, it is incorporated with a large uncertainty.     

Radiotherapy dose enhancement using BNCT in conventional LINACs high-energy treatment: Simulation and experiment

Aim

To employ the thermal neutron background that affects the patient during a traditional high-energy radiotherapy treatment for BNCT (Boron Neutron Capture Therapy) in order to enhance radiotherapy effectiveness.

Background

Conventional high-energy (15–25 MV) linear accelerators (LINACs) for radiotherapy produce fast secondary neutrons in the gantry with a mean energy of about 1 MeV due to (γ, n) reaction. This neutron flux, isotropically distributed, is considered as an unavoidable undesired dose during the treatment. Considering the moderating effect of human body, a thermal neutron fluence is localized in the tumour area: this neutron background could be employed for BNCT by previously administering ¹⁰B-Phenyl-Alanine (¹⁰BPA) to the patient.

Materials and methods

Monte Carlo simulations (MCNP4B-GN code) were performed to estimate the total amount of neutrons outside and inside human body during a traditional X-ray radiotherapy treatment.Moreover, a simplified tissue equivalent anthropomorphic phantom was used together with bubble detectors for thermal and fast neutron to evaluate the moderation effect of human body.

Results

Simulation and experimental results confirm the thermal neutron background during radiotherapy of 1.55E07 cm⁻² Gy⁻¹.The BNCT equivalent dose delivered at 4 cm depth in phantom is 1.5 mGy-eq/Gy, that is about 3 Gy-eq (4% of X-rays dose) for a 70 Gy IMRT treatment.

Conclusions

The thermal neutron component during a traditional high-energy radiotherapy treatment could produce a localized BNCT effect, with a localized therapeutic dose enhancement, corresponding to 4% or more of photon dose, following tumour characteristics. This BNCT additional dose could thus improve radiotherapy, acting as a localized radio-sensitizer.     

Use of planar kV vs. CBCT in evaluation of setup errors in oesophagus carcinoma radiotherapy

Aim

The aim of this study is to evaluate differences in terms of the setup errors observed using kV planar image compared to CBCT for oesophageal cancer patients.

Background

Planar kV images are quick to acquire but only allow the observation of bony structures. CBCT allows the evaluation of soft tissues, which includes the oesophagus (and tumour) and OAR, giving a more accurate verification of the positioning.

Materials and Methods

All patients were imaged with both techniques between January 2012 and March 2014 were included in the study (16 patients, 212 kV images and 116 CBCT images). Differences between the setup errors observed on the two images modalities were studied. A correlation study between TNM staging, tumour location and immobilization systems with setup errors was also done. Finally, the calculation of systematic and random errors allowed to determine the CTV–PTV margin.

Results

A significant discrepancy (p < 0.05) between the setup errors observed with kV and CBCT was observed in the lateral direction. No statistical correlation was found between setup errors and tumour location, immobilization system or TNM staging. The CTV–PTV margin was smaller with CBCT in the vertical (0.6 cm vs. 0.9 cm) and longitudinal (0.7 cm vs. 1 cm) directions and smaller with kV for the lateral directions (0.8 cm vs. 0.9 cm).

Conclusions

The chosen modality influences the setup error observed which will influence the correction applied. Allowing a better observation of the volumes of interest, CBCT should be the modality of choice in this pathology. The CTV–PTV margins could be shrunk if CBCT is used.     

Racial differences in the burden of coronary artery calcium and carotid intima media thickness between Blacks and Whites

Background

Identification of racial differences in the burden and correlates of carotid intima media thickness (CIMT) and coronary artery calcium (CAC) may provide the basis for the development of race-specific cardiovascular disease (CVD) risk prediction algorithms.

Methods

In the Heart Strategies Concentrating on Risk Evaluation (Heart SCORE) study, CIMT was measured by carotid ultrasonography in 792 individuals (35 % Black). CIMT >1 mm was considered significant. CAC was quantified by electron beam computed tomography in 776 individuals (46 % Black). CAC was considered significant if the Agatston score was >100. Cross-sectional associations between race, CIMT and CAC were assessed using logistic regression models.

Results

Blacks had greater CIMT (mean difference 0.033 mm, 95 % CI 0.005–0.06 mm; p = 0.02) and 1.5-fold (95 % CI 1.0–2.3) higher odds of having significant CIMT than Whites. Blacks had less CAC than Whites (mean Agatston score difference 66, [11–122]; p = 0.02) and 50 % lower odds of a significant CAC score compared with Whites (0.5 [0.3–0.7]). These associations were virtually unchanged after adjustment for CVD risk factors. Of the novel CVD risk markers assessed, small-dense low-density lipoprotein was independently associated with increased odds of significant CIMT, with the association being similar among Blacks and Whites (odds ratio [95 % CI]: 1.7 [1.2–2.5] and 1.4 [1.0–1.8] per 1-SD higher level, respectively). Interleukin-6 was significantly associated with CAC among Blacks (1.4 [1.0–2.0]).

Conclusion

Black race is independently associated with greater CIMT but less CAC than White race. CVD risk stratification strategies that incorporate these measures of subclinical atherosclerosis should consider race-specific algorithms.

Electronic supplementary material

The online version of this article (doi:10.1007/s12471-014-0610-4) contains supplementary material, which is available to authorized users.     

Comparison of two treatment strategies for irradiation of regional lymph nodes in patients with breast cancer: Lymph flow guided portals versus standard radiation fields

Aim and Background

Radiotherapy being an essential part of breast cancer treatment, we evaluate various radiotherapy strategies in patients with breast cancer.

Materials and methods

Lymph node (LN) scintigraphy was performed in 172 primary patients with BC. LN visualization started 30–360 min after intratumoral injection of 75–150 MBq of 99mTc-nanocolloids.Our standard recommendation for postoperative radiotherapy in patients with LN invasion by BC were as follows: for patients with external localization of tumour – breast + axillary (Ax) + sub-supraclavicular (SSCL) regions; with internal localization – all above + internal mammary nodes (IM). Proposed strategy of lymph flow guided radiotherapy is based on the assumption that only regions that contain ‘hot’ LNs must be included in a treatment volume.

Results

Among 110 patients with external localization of BC, Ax LNs were visualized in all cases and in 62 patients it was the only region with ‘hot’ LN. Twenty-three patients (20.9%) had drainage to Ax + SSCL, 12 (10.9%) – Ax + IM, 13 (11.8%) – Ax + SSCL + IM regions. After the visualization of lymph flow patterns, standard treatment volume was changed in 87/110 cases (79.1%): in 56.4%, reduced, in 22.7%, enlarged or changed.In 62 patients with tumours in internal quadrants, we revealed the following patterns of lymph-flow: only to the Ax region in 23 (37.1%); Ax + IM, 13 (21%); Ax + SSCL, 15 (24.2%); Ax + IM + ISSCL, 11 (17.7%) cases. After lymph-flow visualization, the standard irradiation volume was reduced in 53/62 (85.5%) cases.

Conclusion

Visualization of an individual lymph flow pattern from BC can be used for the optimization of standard fields used for irradiation of regional LNs.     

Toxicity outcome in patients treated with modulated arc radiotherapy for localized prostate cancer

Aim

This study evaluates the acute toxicity outcome in patients treated with RapidArc for localized prostate cancer.

Background

Modern technologies allow the delivery of high doses to the prostate while lowering the dose to the neighbouring organs at risk. Whether this dosimetric advantage translates into clinical benefit is not well known.

Materials and methods

Between December 2009 and May 2012, 45 patients with primary prostate adenocarcinoma were treated using RapidArc. All patients received 1.8 Gy per fraction, the median dose to the prostate gland, seminal vesicles, pelvic lymph nodes and surgical bed was 80 Gy (range, 77.4–81 Gy), 50.4 Gy, 50.4 Gy and 77.4 Gy (range, 75.6–79.2 Gy), respectively.

Results

The time between the last session and the last treatment follow up was a median of 10 months (range, 3–24 months). The incidence of grade 3 acute gastrointestinal (GI) and genitourinary (GU) toxicity was 2.2% and 15.5%, respectively. Grade 2 acute GI and GU toxicity occurred in 30% and 27% of patients, respectively. No grade 4 acute GI and GU toxicity were observed. Older patients (>median) or patients with V60 higher than 35% had significantly higher rates of grade ≥2 acute GI toxicity compared with the younger ones.

Conclusions

RapidArc in the treatment of localized prostate cancer is tolerated well with no Grade >3 GI and GU toxicities. Older patients or patients with higher V60 had significantly higher rates of grade ≥2 acute GI toxicity. Further research is necessary to assess definitive late toxicity and tumour control outcome.     

Postoperative radiotherapy in prostate cancer: Analysis of prognostic factors in a series of 282 patients

Aim

To assess the outcomes of patients treated with postoperative RT in relation to the possible prognostic factors.

Background

Postoperative radiotherapy (RT) has been proved to reduce the risk of biochemical recurrence in high-risk prostate cancer patients. Baseline prostate specific antigen (PSA), pathological Gleason score (GS), positive surgical margins, nodal status and seminal vesicle invasion are independent predictors of biochemical relapse.

Materials and methods

The clinical records of 282 patients who underwent postoperative RT were retrospectively reviewed. The prognostic value of postoperative PSA, preoperative risk class, nodal status, pathological GS, margins status, and administration of hormonal therapy (HT) was analyzed.

Results

Postoperative RT was delivered with a median dose to the prostatic fossa of 66 Gy (range 50–72) in 1.8–2 Gy/fraction. Median follow-up was 23.1 months (range 6–119). Five-year actuarial biochemical disease-free survival (bDFS) and overall survival rates were 76% and 95%, respectively. Higher bDFS was found for patients with postoperative PSA <0.02 ng/ml (p = 0.03), low preoperative risk class (p = 0.01), pN0 (p = 0.003), GS 4–6 (p = 0.0006), no androgen deprivation therapy (p = 0.02), and irrespective of surgical margin status (p = 0.10). Multivariate analysis showed that postoperative PSA and Gleason score had a significant impact on bDFS (p = 0.039 and p = 0.05, respectively).

Conclusions

Postoperative RT with a dose of 66 Gy offers an acceptable toxicity and an optimal disease control after radical prostatectomy in patients with different risk features. A postoperative PSA >0.02 ng/ml could be considered as a prognostic factor and a tool to select patients at risk for progression.     

Vacuum-assisted core-needle biopsy as a diagnostic and therapeutic method in lesions radiologically suspicious of breast fibroadenoma

Background

Treatment of breast fibroadenoma remains a subject of clinical discussion. Recommended methods include clinical observation or surgical excision of the lesion. The procedure involves hospitalisation and anaesthesia, leaving a scar on the breast.

Aim

The aim of this study was to present the Centre''s experience in removing lesions radiologically suspicious of fibroadenoma by means of an ultrasound-guided vacuum-assisted core-needle biopsy as an alternative to a classical surgery.

Materials and methods

Between March 2007 and April 2010, 196 ultrasound-guided vacuum-assisted biopsies were performed in the Mammotome Biopsy Laboratory of the 1st Surgical Oncology and General Surgery Department at the Greater Poland Cancer Centre in Poznań. The procedure was delivered to female patients aged 17–91 years (mean 40.8, median 39). Qualified for removal were ultrasound identified lesions described as fibroadenomas.

Results

The average size of excised lesions according to pre-biopsy ultrasound image was 13.53 ± 8.92 mm (median 11 mm, range 4–60 mm). In 184 cases (93.9%), benign lesions were found in the final histopathologic examination. Pre-cancer lesions were found in 10 cases, and invasive lesions in two cases. Overall, after follow-up ultrasound examination, four patients were qualified for subsequent surgical resection of lesions that had been left behind.

Conclusion

Vacuum core-needle biopsy is an effective tool enabling removal of breast fibroadenomas. It combines features of a lesion resection and histopathologic material collection providing an access with minimum invasiveness.     

Radiotherapy applications of patients with malignant mesothelioma: A single center experience

Background

In the management of malignant pleural mesothelioma, radiotherapy has been used for the purpose of prophylaxis to reduce the incidence of recurrence at surgical insertion sites or palliate the symptoms.

Aim

The purpose of the study was to evaluate the techniques and effectiveness of radiotherapy in malignant pleural mesothelioma.

Materials and methods

Forty-four (18 female, 26 male) patients diagnosed with malignant pleural mesothelioma were retrospectively evaluated. All patients had surgery or thoracoscopic biopsy for diagnosis, staging or treatment and all received palliative or prophylactic radiotherapy. Fifty-seven percent of the patients received chemotherapy.

Results

Prophylactic radiation was applied to 27 patients with 4–15 MeV electron energies. The median radiotherapy dose was 30 Gy with 3 Gy daily fraction dose. During treatment, 12 patients had grade 1 erythema according to the RTOG scale. In 3 (12%) patients, a local failure at treatment field was observed. Palliative radiotherapy was applied to 17 patients for pain palliation. The median radiation dose was 40 Gy with 2 Gy daily fraction dose by using 6–18 MV photon and/or 4–12 MeV electron energies. Two patients had grade 1 erythema and one patient had grade 2 odynophagy according to the RTOG scale. For 10 (59%) patients, palliation of chest pain was delivered. No late toxicity was observed for all cases.

Conclusion

Our experience showed that prophylactic and palliative radiotherapy are effective and safe therapy modalities in malignant pleural mesothelioma in preventing seeding metastasis at intervention sites or relieving pain. Prospective randomized studies are still needed to determine the benefits of radiotherapy application and to indicate optimum dose schemes.     

3D conformal hypofractionated radical radiotherapy in early glottic cancer

Aim

The purpose of this study was to evaluate acute and late toxicity and the locoregional control in patients treated with hypofractionated radical radiotherapy 2.25 Gy/fraction/day for early glottic carcinoma.

Materials and methods

A retrospective analysis was performed of 27 patients, stage T1–T2 N0 glottic squamous cell carcinoma, that underwent radical RT from April 2008 to October 2011. The mean age was 64.6 years (range 36–81). Seventeen patients were staged T1a, 3 patients T1b and 7 patients T2. All patients were 3D planned and treated in a 6 MV LINAC, 2.25 Gy/fraction/5 days per week, to a total dose between 63 Gy and 67.5 Gy. Biological Effective Dose (BED (α/β = 10)) ranged from 77.18 Gy to 82.69 Gy and EQD2 from 64.31 Gy to 68.91 Gy. Patients were evaluated in periodic follow-up. Toxicity was evaluated according to RTOG Toxicities Scales.

Results

With a median follow-time of 24.7 months (range 3.6–44.2 months), no evidence of locoregional recurrence was observed. The treatment was well tolerated and no unscheduled interruptions in treatments for toxicity were documented, with the median overall treatment time of 41 days (range 38–48). Only grades 1 and 2 acute toxicity were observed and no evidence of severe late toxicity.

Conclusion

The authors believe that this moderately hypofractionated scheme can provide a good locoregional control for T1–T2 glottic carcinomas with no increase of toxicity. As the limitation of this work is the reduced number of patients and the lack of long term follow-up, the authors hope to update this retrospective study in the future in order to improve the power of the results.     

The effects of tracking responses and the day of mailing on physician survey response rate: three randomized trials

Background

The response rates to physician postal surveys remain modest. The primary objective of this study was to assess the effect of tracking responses on physician survey response rate (i.e., determining whether each potential participant has responded or not). A secondary objective was to assess the effects of day of mailing (Monday vs. Friday) on physician survey response rate.

Methods

We conducted 3 randomized controlled trials. The first 2 trials had a 2×2 factorial design and tested the effect of day of mailing (Monday vs. Friday) and of tracking vs. no tracking responses. The third trial tested the effect of day of mailing (Monday vs. Friday). We meta-analyzed these 3 trials using a random effects model.

Results

The total number of participants in the 3 trials was 1339. The response rate with tracked mailing was not statistically different from that with non-tracked mailing by the time of the first reminder (RR = 1.01 95% CI 0.84, 1.22; I² = 0%). There was a trend towards lower response rate with tracked mailing by the time of the second reminder (RR = 0.91; 95% CI 0.78, 1.06; I² = 0%). The response rate with mailing on Mondays was not statistically different from that with Friday mailing by the time of first reminder (RR = 1.01; 95% CI 0.87, 1.17; I² = 0%), and by the time of the 2^nd reminder (RR = 1.08; 95% CI 0.84, 1.39; I² = 77%).

Conclusions

Tracking response may negatively affect physicians'' response rate. The day of mailing does not appear to affect physicians'' response rate.     

Distribution of Central Corneal Thickness and its Association with Ocular Parameters in a Large Central European Cohort: The Gutenberg Health Study

Main objective

To evaluate the distribution of central corneal thickness (CCT) in a large German cohort and to analyse its relationship with intraocular pressure and further ocular factors.

Design

Population-based, prospective, cohort study.

Methods

The Gutenberg Health Study (GHS) cohort included 4,698 eligible enrollees of 5,000 subjects (age range 35–74 years) who participated in the survey from 2007 to 2008. All participants underwent an ophthalmological examination including slitlamp biomicroscopy, intraocular pressure measurement, central corneal thickness measurement, fundus examination, and were given a questionnaire regarding glaucoma history. Furthermore, all subjects underwent fundus photography and visual field testing using frequency doubling perimetry.

Results

Mean CCT was 557.3±34.3 µm (male) and 551.6±35.2 µm in female subjects (Mean CCT from right and left eyes). Younger male participants (35–44 years) presented slightly thicker CCT than those older. We noted a significant CCT difference of 4 µm between right and left eyes, but a high correlation between eyes (Wilcoxon test for related samples: p<0.0001). Univariable linear regression stratified by gender showed that IOP was correlated with CCT (p<0.0001). A 10 µm increase in CCT led to an increase in IOP between 0.35–0.38 mm Hg, depending on the eye and gender. Multivariable linear regression analysis revealed correlations between gender, spherical equivalent (right eyes), and CCT (p<.0001 and p = 0.03, respectively).

Conclusions

We observed positive correlations between CCT and IOP and gender. CCT was not correlated with age, contact lens wear, positive family history for glaucoma, lens status, or iris colour.     

Ischemic Stroke Hospital Admission Associated with Ambient Temperature in Jinan,China

Background

This study estimated the effects of ambient temperature and relative humidity on hospital admissions for ischemic stroke during 1990–2009 in Jinan, China.

Methods

To account for possible delayed effects and harvesting effect, we examined the impact of meteorological factors up to 30 days before each admission using a distributed lag non-linear model; we controlled for season, long-term trend, day of week and public holidays in the analysis. Stratified analyses were also done for summer and winter.

Results

A total of 1,908 ischemic stroke hospital admissions were observed between 1990 and 2009. We found a strong non-linear acute effect of daily temperatures on ischemic stroke hospital admission. With the mean temperature 15°C as the reference, the relative risk (RR) was 1.43 (95% confidence interval (CI): 1.10–1.85) for 0°C daily temperature on the same day, and 0.43 (95% CI: 0.31–0.59) for 30°C daily temperature on the same day, respectively. The effect of ambient temperature was similar in summer and winter. No significant association was observed between relative humidity and ischemic stroke hospitalization.

Conclusions

Low temperature might be a risk factor for ischemic stroke, and high temperature might be protective factor of ischemic stroke occurrence in Jinan, China.