Adjuvant radiotherapy for breast cancer significantly improves overall survival: the missing link.

BACKGROUND AND PURPOSE: The influence of surgical adjuvant radiotherapy on overall survival of patients with operable breast cancer is still a controversial subject. The negative result of the EBCTCG meta-analysis (Early breast cancer trialists', collaborative group. Effects of radiotherapy and surgery in early breast cancer. An overview of the randomised trials. N. Engl. J. Med. 1995;333:1444-1455) of clinical randomized trials on adjuvant radiotherapy in breast cancer is in strong contrast with the Danish 82B, 82C and British Columbia trials (Overgaard M, Hanse PS, Overgaar J, et al. Postoperative radiotherapy in high-risk premenopausal women with breast cancer who receive adjuvant chemotherapy. Danish Breast Cancer Cooperative Group 82b Trial. N. Engl. J. Med. 1997;337:949-955; Overgaard M, Jensen MB, Overgaard J, et al. Postoperative radiotherapy in high-risk postmenopausal breast-cancer patients given adjuvant tamoxifen: Danish Breast Cancer Cooperative Group DBCG 82c randomized trial. Lancet 1999;353:1641-1648; Ragaz J, Jackson S, Le N, et al. Adjuvant radiotherapy and chemotherapy in node-positive premenopausal women with breast cancer. N. Engl. J. Med. 1997;337:956-962) showing an impressive survival benefit. This paper tries to fill in the gap between the conflicting results. MATERIALS AND METHODS: The 36 trials of the EBCTCG (Early breast cancer trialists', collaborative group, 1995) were prospectively screened for a number of objective parameters that are usually not analyzed in review papers. The odds of death data (and its variance) were borrowed from the original meta-analysis (Early breast cancer trialists', collaborative group, 1995) to check whether the objective features were significant predictors for overall survival benefit. RESULTS: A significant survival benefit for the radiotherapy arm was found for recent trials (2P<0.05), large trials (2P<0.03), trials that used standard fractionation (2P<0.02), and trials with a favourable crude survival (2P<0.03). For these four parameters clear parameter-effect relations were found. In recent and large trials the odds reduction was 12.4% (2P=0.004). CONCLUSIONS: Surgical adjuvant radiotherapy significantly improves overall survival of breast cancer patients provided that current techniques are used and treatment is given with standard fractionation. For the best subgroups we observed an odds of death reduction of more than 20%. The results of this study stress the importance of reducing cardiovascular and other late toxicity in adjuvant radiotherapy for breast cancer.

Use of a simulator with CT option in radiotherapy of macular degeneration.

PURPOSE: To assess the accuracy of a conventional simulation procedure in radiotherapy of age-related macular degeneration. METHODS AND MATERIALS: A computed tomographic (CT) extension attached to the treatment simulator was used to acquire CT images immediately after conventional simulation in 18 patients referred for treatment of age-related macular degeneration. Analysis was performed on 16 one-sided treatment cases for whom images were obtained. Error was estimated by the displacement between the observed treatment isocenter and the intended isocenter based on reconstructed eye geometry. RESULTS: Based on single slice measurements, the mean error amplitude was 2.3 mm (range 0.2-5.6). Based on three-dimensional eye globe reconstruction, the mean error amplitude was 2.8 mm (range 0.8-5.3). An incidental finding previously unreported was the lower image quality at the center of the simulator-CT image acquisition field. CONCLUSIONS: Small but significant errors from conventional simulation were noted. The integrated simulation-CT procedure may help correct the errors to improve the accuracy of simulation setup. The lower image quality at the center of image acquisition field requires adaptation of the simulation-CT procedure.

Electronic portal imaging with on-line correction of setup error in thoracic irradiation: clinical evaluation.

PURPOSE: To analyze setup errors and the feasibility of their on-line correction using electronic portal imaging in the irradiation of lung tumors. METHODS AND MATERIALS: Sixteen patients with lung cancer were irradiated through opposed anteroposterior fields. Localization images of anteroposterior fields were recorded with an electronic portal imaging device (EPID). Using an in-house developed algorithm for on-line comparison of portal images setup errors were measured and a correction of table position was performed with a remote couch control prior to treatment. In addition, residual errors were measured on the EPID verification image. Global and individual mean and standard deviation of setup errors were calculated and compared. The feasibility of the procedure was assessed measuring intra- and interobserver variability, influence of organ movement, reproducibility of error measurement, the extra time fraction needed for measuring and adjusting and the fraction of dose needed for imaging. RESULTS: In two setups the procedure could not be finished normally due to problems inherent to the procedure. The reproducibility, intraobserver variability, and influence of organ movements were each described by a distribution with a mean value less than or equal to 1 mm and a standard deviation (SD) of less than 1.5 mm. The interobserver variability showed to be a little bit larger (mean: 0.3 mm, SD: 1.7 mm). The mean time to perform the irradiation of the anteroposterior field was 4 +/- 1 min. The mean time for the measurement and correction procedure approximated 2.5 min. The mean extra time fraction was 65 +/- 24% (1 SD) with more than half of this coming from the error measurement. The dose needed for generation of EPID images was 5.9 +/- 1.4% of total treatment dose. The mean and SD of setup errors were, respectively, 0.1 and 4.5 mm for longitudinal and -2.0 and 5.7 mm for transversal errors. Of 196 measured translational errors 120 (61%) exceeded the adjustment criteria. For individual patients systematic and random setup errors can be as high as, respectively, 15.8 and 7.5 mm. Mean residual error and SD were for longitudinal direction 0.08 and 1.2 mm and for transversal direction -0.9 and 1.0 mm (pooled data). For individuals, the mean residual errors were smaller than 1 mm, with a typical SD per patient of less than 2 mm. CONCLUSION: Setup errors in thoracic radiation therapy are clinically important. On-line correction can be performed accurately with an objective measurement tool, although this prolongs the irradiation procedure for one field with 65%.