[en] Purpose: To investigate whether p53 immunoreactivity is a prognostic factor for survival and pelvic control in rectal carcinoma treated with surgery and postoperative radiotherapy. Methods and Materials: From 1981 through 1989, 146 patients with rectal carcinoma received postoperative radiotherapy and were followed for at least 5 years or until death. The specimens of 123 of these 146 patients could be retrieved and examined immunohistochemically for p53 expression. The prognostic value for survival and pelvic control of p53 expression and other patient and treatment factors was examined by univariate and multivariate analyses. Results: p53 expression has no prognostic significance for overall survival in this group of 123 patients. The only prognostic factor for survival in this material is tumor stage (p < 0.01). The actuarial pelvic recurrence rates of p53- and p53+ cases are different in favor of the p53- ones. In the univariate analysis this difference is significant (p = 0.05). However, in the multivariate analysis the influence of p53 expression, additional to stage, becomes nonsignificant (p = 0.10). This indicates that p53 expression is not a strong independant prognostic factor for pelvic recurrence. In the multivariate analysis stage turns out to be the only predictor of pelvic recurrence (p 0.03). When only recurrences inside the radiation field are considered, there is no difference between p53+ and p53- cases. Conclusion: Based on this material, we have found no convincing evidence that p53 expression is an important predictor of survival or local control in rectal cancer treated with surgery and postoperative radiotherapy. We have found no evidence that possible differences in radiosensitivity between p53+ and p53- tumors have clinical significance for this group of patients

[en] Purpose: To compare the radiopaque vaginal rod method with contrast vaginography in localization of the vagina. Methods and Materials: In 25 female patients who needed pelvic radiotherapy, both our standard localization procedure using the vaginal rod and a localization procedure using contrast vaginography were performed. As a rod can change the position of the vagina, contrast vaginography was considered to display the true anatomic position of the vagina. The corresponding rod and nonrod X-rays of each patient were compared. The distance from the true vaginal apex to the displaced vaginal apex (= the top of the rod) was measured in the sagittal plane. This distance was called the inaccuracy of the rod method. Furthermore, the size of the vaginal vault was measured using the contrast vaginography. Results: The median inaccuracy of the rod method was 13 mm (range 2 to 24 mm). The maximal width of the vagina ranged from 24 to 68 mm in the frontal plane (median 39 mm) and from 3 to 22 mm in the sagittal plane (median 10 mm). Conclusion: The rod method is not accurate to localize the vagina. Furthermore, the rod gives no information on the actual size of the vaginal vault. Contrast vaginography is the method of choice to localize the vagina.

[en] Purpose: To compare the interobserver reliability of the palpation method with the method of measuring tissue compliance with a tissue compliance meter (TCM) on women who underwent breast-conserving surgery and radiotherapy for breast cancer. Methods and Materials: Thirty-eight patients and 30 controls were measured with the palpation method by two radiation oncologists and with the TCM by two physiotherapists. Measurements were taken on four locations of the breasts of all 68 women. Reliability coefficients were computed for both methods. A weighted kappa score was computed for the palpation method and this was compared with the intraclass correlation coefficient (ICC) computed for the TCM method. The conditions for direct comparison of these scores were met in this study. Results: A weighted kappa of 0.65 was computed for the palpation method and an ICC of 0.91 was computed for the TCM method. These scores differ significantly from each other (p < 0.01). Conclusion: The interobserver reliability of the TCM method is superior to that of the palpation method. However, at locations where the TCM is not applicable, palpation is a good alternative

[en] Purpose: For cranial patients receiving stereotactic radiotherapy, we use the Exactrac stereoscopic X-ray system to optimize patient positioning. Patients are immobilized with the BrainLAB Mask System (BrainLAB, Feldkirchen, Germany). We have developed an adapter to this system that accommodates a vacuum mouth piece (VMP). Measurements with the Exactrac system have been performed to study the positioning accuracy after corrections with this system and to evaluate the accuracy of the VMP vs. the standard available upper jaw support (UJS). Methods and Materials: Positioning results were collected for 20 patients with the UJS and 20 patients with the VMP, before treatment (1,122 fractions) and after treatment (400 fractions). For all 6 degrees of freedom the average, the random error and systematic error were calculated. Results: The average vector length before and after correction with the Exactrac system was 2.1 ± 1.2 mm and 0.7 ± 0.6 mm respectively for UJS and 1.7 ± 0.7 mm and 0.4 ± 0.4 mm for VMP. Interfraction positioning for translations was greatly improved after correction with the Exactrac system (p < 0.0005) and is better with VMP than with UJS (p = 0.005). Outliers were greatly reduced. Interfraction rotations were significantly smaller for VMP. Intrafraction errors for vertical and longitudinal translations and for rotations were smaller for the VMP. Conclusions: Positioning correction using the Exactrac X-ray system greatly improves accuracy. Adding the VMP results in even better patient fixation and smaller rotations, making it a useful addition to the Mask System. Combined, this is a convenient and accurate alternative to invasive fixation methods

[en] Purpose: Intensity-modulated radiotherapy (IMRT) and dynamic conformal arc (DCA) are two state-of-the-art techniques for linac-based stereotactic radiotherapy (SRT) using the micromultileaf collimator. The purpose of this planning study is to examine the relative merits of these techniques in the treatment of intracranial tumors. Materials and Methods: SRT treatment plans were made for 25 patients with a glioma or meningioma. For all patients, we made an IMRT and a DCA plan. Plans were evaluated using: target coverage, conformity index (CI), homogeneity index (HI), doses in critical structures, number of monitor units needed, and equivalent uniform dose (EUD) in planning target volume (PTV) and critical structures. Results: In the overall comparison of both techniques, we found adequate target coverage in all cases; a better mean CI with IMRT in concave tumors (p = 0.027); a better mean HI with DCA in meningiomas, complex tumors, and small (< 92 mL) tumors (p = 0.000, p = 0.005, and p = 0.005, respectively); and a higher EUD in the PTV with DCA in convex tumors (gliomas) and large tumors (p = 0.000 and p = 0.003, respectively). In all patients, significantly more monitor units were needed with IMRT. The results of the overall comparison did not enable us to predict the preference for one of the techniques in individual patients. The DCA plan was acceptable in 23 patients and the IMRT plan in 19 patients. DCA was preferred in 18 of 25 patients. Conclusions: DCA is our preferred SRT technique for most intracranial tumors. Tumor type, size, or shape do not predict a preference for DCA or IMRT.

[en] Purpose: Stereotactic radiotherapy (SRT) of brain metastases is considered effective when long-term local control is obtained. However, dose-effect data are scarce. We, therefore, performed a systematic literature search to assess the evidence concerning the relation of SRT dose and local control probability. Methods and materials: A search was performed for papers describing patients treated with SRT for brain metastases, published from 1990 through 2009, in the electronic databases Medline (Pubmed) and Embase. We selected only papers reporting actuarial local control probability, in which a fixed dose had been prescribed and in which the size of the metastases was given. Series with SRT as a boost after whole brain irradiation (WBI) or with SRT after surgery were excluded. From the selected papers we extracted data on dose, local control rates and necrosis rates. Biological effective doses of the linear-quadratic-cubic model, using an α/β of 12 Gy (BED₁₂), were calculated and a dose-response curve was constructed. Results: Eleven papers fulfilled the selection criteria for further analysis. Six-month local control rates were higher than 80% in almost all the series irrespective of dose. Twelve-month local control rates, however, varied and were higher than 80%, higher than 60% and lower than 50% with single doses of ≥21 Gy, ≥18 Gy and ≤15 Gy, respectively, and 70% or higher with fractionated SRT (FSRT). A BED₁₂ of at least 40 Gy was associated with a twelve-month local control rate of 70% or more. Conclusion: Local control after single fraction SRT is highly dependent upon dose and is high (>80%) after 21 Gy or more, but low (<50%) after 15 Gy or less. We conclude that SRT for brain metastases should preferably be applied with a BED₁₂ of at least 40 Gy corresponding with a single fraction of 20 Gy, two fractions of 11.6 Gy or three fractions of 8.5 Gy.

[en] Purpose: The local failure rate in patients with locoregionally advanced cervical cancer is 41-72% after radiotherapy (RT) alone, whereas local control is a prerequisite for cure. The Dutch Deep Hyperthermia Trial showed that combining RT with hyperthermia (HT) improved 3-year local control rates of 41-61%, as we reported earlier. In this study, we evaluate long-term results of the Dutch Deep Hyperthermia Trial after 12 years of follow-up. Methods and Materials: From 1990 to 1996, a total of 114 women with locoregionally advanced cervical carcinoma were randomly assigned to RT or RT + HT. The RT was applied to a median total dose of 68 Gy. The HT was given once weekly. The primary end point was local control. Secondary end points were overall survival and late toxicity. Results: At the 12-year follow-up, local control remained better in the RT + HT group (37% vs. 56%; p = 0.01). Survival was persistently better after 12 years: 20% (RT) and 37% (RT + HT; p = 0.03). World Health Organization (WHO) performance status was a significant prognostic factor for local control. The WHO performance status, International Federation of Gynaecology and Obstetrics (FIGO) stage, and tumor diameter were significant for survival. The benefit of HT remained significant after correction for these factors. European Organization for Research and Treatment of Cancer Grade 3 or higher radiation-induced late toxicities were similar in both groups. Conclusions: For locoregionally advanced cervical cancer, the addition of HT to RT resulted in long-term major improvement in local control and survival without increasing late toxicity. This combined treatment should be considered for patients who are unfit to receive chemotherapy. For other patients, the optimal treatment strategy is the subject of ongoing research

[en] PurposeFor unbiased comparison of different radiation modalities and techniques, consensus on delineation of radiation sensitive organs at risk (OARs) and on their dose constraints is warranted. Following the publication of a digital, online atlas for OAR delineation in neuro-oncology by the same group, we assessed the brain OAR-dose constraints in a follow-up study.