Linda Kašaová

High-dose rate brachytherapy in the treatment of penile carcinoma--first experience.

PURPOSE Interstitial low-dose rate brachytherapy (BRT) allows a conservative treatment of T1-T2 penile carcinoma. High-dose rate (HDR) BRT is often considered as a dangerous method for interstitial implants because of higher risk of complications. However, numerous reports suggest that results of HDR-BRT may be comparable to low-dose rate BRT. There are no data available in the literature regarding HDR interstitial BRT for carcinoma of the penis. METHODS AND MATERIALS Ten patients with early penile carcinoma were treated by interstitial hyperfractionated HDR-BRT at the dose of 18 times 3Gy twice daily between years 2002 and 2009. Breast interstitial BRT template was used for fixation and precise geometry reconstruction of stainless hollow needles. RESULTS Median followup was 20 months. Our BRT technique and fractionation schedule was well tolerated by all patients. Acute reaction consisted predominantly of penis edema and Grade 2 radiation mucositis that dissolved during 8 weeks after the treatment. We neither observed any postradiation necrosis nor urethral stenosis. The worst late side effects recorded were mild telanagiectasias in the treatment region. At the last followup, all patients were alive without evidence of the tumor and with fully functional organ. CONCLUSIONS Hyperfractionated interstitial HDR-BRT with 18 times 3 Gy per fraction twice daily is a promising method in selected patients of penile carcinoma and deserves further evaluation in a larger prospective study.

Utilization of cone‐beam CT for reconstruction of dose distribution delivered in image‐guided radiotherapy of prostate carcinoma — bony landmark setup compared to fiducial markers setup

The purpose of this study was to compare two different styles of prostate IGRT: bony landmark (BL) setup vs. fiducial markers (FM) setup. Twenty‐nine prostate patients were treated with daily BL setup and 30 patients with daily FM setup. Delivered dose distribution was reconstructed on cone‐beam CT (CBCT) acquired once a week immediately after the alignment. Target dose coverage was evaluated by the proportion of the CTV encompassed by the 95% isodose. Original plans employed 1 cm safety margin. Alternative plans assuming smaller 7 mm margin between CTV and PTV were evaluated in the same way. Rectal and bladder volumes were compared with initial ones. While the margin reduction in case of BL setup makes the prostate coverage significantly worse (p=0.0003, McNemars test), in case of FM setup with the reduced 7 mm margin, the prostate coverage is even better compared to BL setup with 10 mm margin (p=0.049, Fishers exact test). Moreover, partial volumes of organs at risk irradiated with a specific dose can be significantly lowered (p<0.0001, unpaired t‐test). Reducing of safety margin is not acceptable in case of BL setup, while the margin can be lowered from 10 mm to 7 mm in case of FM setup. PACS numbers: 87.55.dk, 87.55.km, 87.55.tm

High-dose-rate brachytherapy in early oral cancer with close or positive margins

PURPOSE Retrospective evaluation of high-dose-rate brachytherapy (HDR BT) in early oral cancer and factors influencing tumor control. METHODS AND MATERIALS A total of 30 patients with T1-T3N0 tongue and floor of mouth cancer were treated with tumor excision±elective neck dissection and HDR BT 18×3 Gy b.i.d. The Kaplan-Meier model was used for survival analyses, and the log-rank test and Cox regression analyses were used to evaluate the influence of T-stage, histologic grade, resection margin, depth of invasion, and vascular endothelial growth factor (VEGF) intensity on local control (LC), nodal control (NC), disease-free survival (DFS), and overall survival (OS). Median followup was 40 months (6-145). RESULTS Actuarial 3-year LC, NC, DFS, DFS after salvage treatment, and OS were 85.4%, 69.2%, 65.4%, 75.6%, and 73.0%, respectively. The log-rank test and univariate Cox regression analysis revealed the following correlations, namely tumor grade correlated with LC, DFS, and OS; T-stage with NC and DFS; depth of invasion and VEGF intensity with NC, DFS, and OS. Associations detected on the multivariate analysis were as follows: tumor grade with LC, depth of invasion with NC, depth of invasion and tumor grade with DFS, and VEGF intensity with DFS after salvage treatment. Only one case of osteoradionecrosis and two cases of soft tissue necrosis occurred. CONSLUSION The HDR BT 18×3 Gy b.i.d. is a safe treatment of early oral cancer with a good LC. The T-stage, tumor grade, depth of invasion, and intensity of VEGF were significant predictors of locoregional control.

Daily prostate volume anD position monitoring using implanteD golD markers anD on-boarD imaging During raDiotherapy

PURPOSE This study aimed to evaluate prostate volume changes and prostate motions during radiotherapy. METHODS In 2010, twenty-five patients were treated for prostate cancer by external beam radiotherapy with implanted fiducial markers. Coordinates of three gold markers on kilovoltage images were calculated daily. Volume changes in target structure were observed through changes in intermarker distances. Differences in patient position between laser-tattoo alignment and gold marker localization were evaluated. Intrafraction motion was assessed by measuring marker displacement on kilovoltage images acquired before and after fraction delivery. RESULTS Prostate shrinkage was observed in 60% of patients. The average shrinkage was 7% of the prostates initial volume. Corrections after laser-tattoo alignment remained mostly below 1 cm. The difference between marker centroid position on the actual images and the planning images was 2 +/- 1 mm on average. The extension of intrafraction movements was 7.6 +/- 0.2 mm on average. CONCLUSIONS In our retrospective study, the possibility for prostate volume changes during radiotherapy was revealed. Intrafraction movements turned out to be the limiting factor in safety margin reduction.

Predicting factors for locoregional failure of high-dose-rate brachytherapy for early-stage oral cancer

AIM Brachytherapy is an alternative to surgery in the treatment of the early stages of oral tongue cancer. The aim of this retrospective study was to analyze the clinical risk factors and possible candidate biomarkers of local and regional tumor control. PATIENTS & METHODS Twenty-four patients were treated between the years 2001 and 2010. Median follow-up was 37.4 months. Correlation between disease-free survival and clinical stage, tumor grade, resection margin, depth of invasion, and p16, EGF receptor, NF-κB, HIF-1α, HER2, Ku-80, COX-2 and VEGF expression was evaluated. RESULTS The estimated 5-year local control was 81% and locoregional control was 62%. Depth of tumor invasion (p = 0.018) and higher VEGF expression (p = 0.016) were significantly predictive for worse disease-free survival in Cox multivariate analysis. CONCLUSION Intensity of VEGF expression and depth of tumor invasion may be significantly negative predictors of disease-free survival in tongue cancer patients treated by brachytherapy alone. Predictive value of VEGF deserves evaluation in larger studies.