Comment on: Conservative surgery and radiotherapy in early stage breast cancer: A comparison between tumourectomy and quadrantectomy [3] (multiple letters)

SCOPUS: le.jinfo:eu-repo/semantics/publishe

Post-surgery radiation in early breast cancer: survival analysis of registry data

Background and purpose: Overviews of randomized trials have shown a small survival advantage with post-surgery radiation in early breast cancer. The present study attempts to extend this observation through a systematic analysis of population data. Materials and methods: This retrospective cohort study used the Surveillance, Epidemiology, and End Results (SEER) data on 83,776 women with breast cancer diagnosed between 1988 and 1997, stage T1-T2, node negative or node positive. The analysis was performed using the proportional hazard models. Results: Radiation was associated with a reduced mortality after breast-conserving surgery in node negative patients (hazard ratio 0.757; 95% confidence interval 0.709-0.809; using total mastectomy without radiation as reference) and in node positive patients (hazard ratio 0.777; 0.717-0.842), and after total mastectomy in node positive patients (hazard ratio 0.885; 0.815-0.961). Radiation was associated with an increased hazard ratio of 1.271 (1.080-1.496) after total mastectomy in node negative patients. Without radiation, breast-conserving surgery in node negative patients was associated with an increased hazard ratio (1.167; 1.036-1.314); a similar increase was not observed in node positive patients (hazard ratio 1.011; 0.884-1.155). In all cases, the best survival rates were found with combined breast-con serving surgery and radiation. Conclusion: The available data indicate that post-surgery radiation provides a survival advantage irrespective of the type of surgery in node positive patients. Likewise, survival advantage was observed with post-surgery radiation and breast-conserving procedure in node negative patients. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved

X-ray-assisted positioning of patients treated by conformal arc radiotherapy for prostate cancer: Comparison of setup accuracy using implanted markers versus bony structures

Purpose: The aim of this study was to compare setup accuracy of NovalisBody stereoscopic X-ray positioning using implanted markers in the prostate vs. bony structures in patients treated with dynamic conformal arc radiotherapy for prostate cancer. Methods and Materials: Random and systematic setup errors (RE and SE) of the isocenter with regard to the center of gravity of three fiducial markers were measured by means of orthogonal verification films in 120 treatment sessions in 12 patients. Positioning was performed using NovalisBody semiautomated marker fusion. The results were compared with a control group of 261 measurements in 15 patients who were positioned with NovalisBody automated bone fusion. In addition, interfraction and intrafraction prostate motion was registered in the patients with implanted markers. Results: Marker-based X-ray positioning resulted in a reduction of RE as well as SE in the anteroposterior, craniocaudal, and left-right directions compared with those in the control group. The interfraction prostate displacements with regard to the bony pelvis that could be avoided by marker positioning ranged between 1.6 and 2.8 mm for RE and between 1.3 and 4.3 mm for SE. Intrafraction random and systematic prostate movements ranged between 1.4 and 2.4 mm and between 0.8 and 1.3 mm, respectively. Conclusion: The problem of interfraction prostate motion can be solved by using implanted markers. In addition, the NovalisBody X-ray system performs more accurately with markers compared with bone fusion. Intrafraction organ motion has become the limiting factor for margin reduction around the clinical target volume. © 2007 Elsevier Inc. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A feasibility study of high dose rate brachytherapy in solitary urinary bladder cancer

Purpose: To determine the feasibility of high dose rate brachytherapy in the treatment of T1-T3 solitary bladder cancer and to compare results and side-effects to those obtained by others using conventional, i.e. low dose rate regimens. Methods and Materials: Between July 1992 and 1995, 16 patients entered the study. Median age at diagnosis was 64 years (range: 45-79 years). Diagnostic transurethral resection showed four T1, five T2, and seven T3 lesions, all proven solitary by random biopsies. Radiotherapy consisted of low-dose preoperative external beam irradiation (3 x 3.5 Gy on the 3 consecutive days prior to implantation), followed by high dose rate brachytherapy (15 x 3 Gy during the 8 consecutive days thereafter). Median follow-up from the date of implantation was 23 months (range: 6-43 months). In 15 patients, cystoscopy was systematically performed during follow-up, whereas the 16th patient was followed on a clinical basis only. Results: Recurrences have occurred in 2 of 15 evaluable patients (both stage T3): metastasis in 1 and combined local plus distant failure in the other patient. Cystoscopic evaluation showed persisting alterations of the implanted portion of the bladder mucosa in 11 of 15 evaluable patients (ulceration, calcifications, and/or punctiform bleedings). Symptomatic radiation cystiris was mild and transient in 14 but persisting and severe in 2 patients. Conclusion: This study documents the feasibility of high dose rate brachytherapy in a selected group of bladder cancer patients. Both patient outcome and side-effects are comparable to the best results obtained with low dose rate schedules. Additional follow-up is still needed to enforce the comparison.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

CLINICAL AND DOSIMETRIC PREDICTORS OF ACUTE TOXICITY AFTER A 4-WEEK HYPOFRACTIONATED EXTERNAL BEAM RADIOTHERAPY REGIMEN FOR PROSTATE CANCER: RESULTS FROM A MULTICENTRIC PROSPECTIVE TRIAL

Purpose: To investigate predictors for gastrointestinal (GI) and genitourinary (GU) acute toxicity after a short-course hypofractionated radiotherapy regimen for prostate cancer. Materials and Methods: Three institutions included 102 patients with TI-T3N0M0 prostate cancer in a Phase II study. Patients were treated with 56 Gy in 16 fractions over 4 weeks. Acute toxicity was scored weekly during treatment and I and 2 months after treatment using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria extended with additional symptoms and the International Prostate Symptom Index (IPSS). Correlation with a number of clinical and dosimetric parameters was assessed by univariate and multivariate analyses. Results: No Grade 3 or 4 GI side effects were observed. Grades I and 2 rectal GI toxicity occurred in 36%, and 38%, respectively. Corresponding figures for Grades 1 and 2 GU toxicity were 42% and 39%, respectively. Grade 3 or higher GU toxicity was detected in 4% of patients. In multivariate analysis, percent rectal volumes higher than 8% receiving doses >= 53 Gy (V-53) were statistically correlated to Grade 2 acute rectal reaction (p = 0.006). For GU morbidity, only the IPSS pretreatment score was independently associated (p = 0.0036) with an increase in GU acute effects. Conclusions: Acute GU and GI toxicity were comparable with other series. Our data show that increased incidence and intensity of acute toxicity is a transient effect related to shorter overall treatment time rather than a larger effect in biological equivalent dose with respect to a conventional fractionation regime

Assessment of the uncertainties in dose delivery of a commercial system for linac-based stereotactic radiosurgery

Purpose: Linac-based stereotactic radiosurgery (SRS) was introduced in our department in 1992, and since then more than 200 patients have been treated with this method. An in-house-developed algorithm for target localization and dose calculation has recently been replaced with a commercially available system. In this study both systems have been compared, and positional accuracy, as well as dose calculation, have been verified experimentally. Methods and Materials: The in-house-developed software for target localization and dose calculation is an extension to George Sherouse's GRATIS® software for radiotherapy treatment planning, and has been replaced by a commercial (BrainSCAN version 3.1; BrainLAB, Germany) treatment planning system (TPS) for SRS. The positional accuracy for the entire SRS procedure (from image acquisition to treatment) has been investigated by treatment of simulated targets in the form of 0.2-cm lead beads inserted into an anthropomorphic phantom. Both dose calculation algorithms have been verified against manual calculations (based on basic beam data and CT data from phantom and patients), and measurements with the anthropomorphic phantom applying ionization chamber, thermoluminescent detectors, and radiographic film. This analysis has been performed on a variety experimental situations, starting with static beams and simple one-arc treatments, to more complex and clinical relevant applications. Finally, 11 patients have been evaluated with both TPS in parallel for comparison an continuity of clinical experience. Results: Phantom studies evaluating the entire SRS procedure have shown that a target, localized by CT, can be irradiated with a positional accuracy of 0.08 cm in any direction with 95% confidence. Neglecting the influencing of dose perturbation when the beam passes through bone tissue or air cavities, the calculated dose values obtained from both TPSs agreed within 1% (SD 1%) for phantom and patient studies. The application of a one dimensional path length correction for tissue heterogeneity influences the treatment prescription 4% on average (SD 1%), which is in compliance with theoretical predictions. The phantom measurements confirmed the predicted dose at isocenter within uncertainty for the different treatment schedules in this study. Conclusion: The full SRS procedure applied to an anthropomorphic phantom has been used as a comprehensive method to assess the uncertainties involved in dose delivery and target positioning. The results obtained with both TPSs are in agreement with AAPM Report 54, TG 42 and clinical continuity is assured. However, the use of one-dimensional path length correction will result in an increase of 4% in dose prescription, which is slightly more than that predicted in the literature.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Clinical use of stereoscopic X-ray positioning of patients treated with conformal radiotherapy for prostate cancer.

PURPOSE: To evaluate accuracy and time requirements of a stereoscopic X-ray-based positioning system in patients receiving conformal radiotherapy to the prostate. METHODS AND MATERIALS: Setup errors of the isocenter with regard to the bony pelvis were measured by means of orthogonal verification films and compared to conventional positioning (using skin drawings and lasers) and infrared marker (IR) based positioning in each of 261 treatments. In each direction, the random error represents the standard deviation and the systematic error the absolute value of the mean position. Time measurements were done in 75 treatments. RESULTS: Random errors with the X-ray positioning system in the anteroposterior (AP), lateral, and longitudinal direction were (average +/- 1 standard deviation) 2 +/- 0.6 mm, 1.7 +/- 0.6 mm, and 2.4 +/- 0.7 mm. The corresponding values of conventional as well as IR positioning were significantly higher (p or=5 mm occurred in 2%-14% of treatments after X-ray positioning, 13%-29% using IR markers, and 28%-53% with conventional positioning. Total linac time for one treatment session was 14 min 51 s +/- 4 min 18 s, half of which was used for the X-ray-assisted positioning procedure. CONCLUSION: X-ray-assisted patient positioning significantly improves setup accuracy, at the cost of an increased treatment time.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Initial clinical experience with infrared-reflecting skin markers in the positioning of patients treated by conformal radiotherapy for prostate cancer

Purpose: To evaluate an infrared (IR) marker-based positioning system in patients receiving conformal radiotherapy for prostate cancer. Methods and materials: During 553 treatments, the ability of the IR system to automatically position the isocenter was recorded. Setup errors were measured by means of orthogonal verification films and compared to conventional positioning (using skin drawings and lasers) in 184 treatments. Results: The standard deviation of anteroposterior (AP) and lateral setup errors was significantly reduced with IR marker positioning compared to conventional: 2 vs. 4.8 mm AP (p < 0.01) and 1.6 vs. 3.5 mm laterally (p < 0.01). Longitudinally, the difference was not significant (3.5 vs. 3.0 mm). Systematic errors were on the average smaller AP and laterally for the IR method: 4.1 vs. 7.8 mm AP (p = 0.01) and 3.1 vs. 5.6 mm lateral (p = 0.07). Longitudinally, the IR system resulted in somewhat larger systematic errors: 5.0 vs. 3.4 mm for conventional positioning (p = 0.03). The use of an off-line correction protocol, based on the average deviation measured over the first four fractions, allowed virtual elimination of systematic errors. Inability of the IR system to correctly locate the markers, leading to an executional failure, occurred in 21% of 553 fractions. Conclusion: IR marker-assisted patient positioning significantly improves setup accuracy along the AP and lateral axes. Executional failures need to be reduced. © 2002 Elsevier Science Inc.SCOPUS: ar.jinfo:eu-repo/semantics/publishe