Biomedical subjects

Boguslaw Maciejewski

Publications and source records attributed to Boguslaw Maciejewski.

9 recordsLinked to original sources

PubMed2006

Continuous accelerated 7-days-a-week radiotherapy for head-and-neck cancer: long-term results of phase III clinical trial.

PURPOSE: To update 5-year results of a previously published study on special 7-days-a-week fractionation continuous accelerated irradiation (CAIR) for head-and-neck cancer patients. METHODS AND MATERIALS: One hundred patients with squamous cell carcinoma of head and neck in Stage T(2-4)N(0-1)M(0) were randomized between two definitive radiation treatments: accelerated fractionation 7 days a week including weekends (CAIR) and conventional 5 days a week (control). Hence the overall treatment time was 2 weeks shorter in CAIR. RESULTS: Five-year local tumor control was 75% in the CAIR group and 33% in the control arm (p < 0.00004). Tumor-cure benefit corresponded with significant improvement in disease-free survival and overall survival rates. Confluent mucositis was the main acute toxicity, with the incidence significantly higher in CAIR patients than in control (respectively, 94% vs. 53%). When 2.0-Gy fractions were used, radiation necrosis developed in 5 patients (22%) in the CAIR group as a consequential late effect (CLE), but when fraction size was reduced to 1.8 Gy no more CLE occurred. Actuarial 5-year morbidity-free survival rate was similar for both treatments. CONCLUSIONS: Selected head-and-neck cancer patients could be treated very effectively with 7-days-a-week radiation schedule with no compromise of total dose and with slight 10% reduction of fraction dose (2 Gy-1.8 Gy), which article gives 1 week reduction of overall treatment time compared with standard 70 Gy in 35 fractions over 47-49 days. Although this report is based on the relatively small group of patients, its results have encouraged us to use CAIR fractionation in a standard radiation treatment for moderately advanced head-and-neck cancer patients.

Adult↗

PubMed2005

Randomized clinical trial on continuous 7-days-a-week postoperative radiotherapy for high-risk squamous cell head-and-neck cancer: a report on acute normal tissue reactions.

BACKGROUND AND PURPOSE: To analyse acute mucosal reactions in patients treated with continuous accelerated postoperative irradiation (p-CAIR) compared to conventionally fractionated postoperative radiotherapy (p-CF). PATIENTS AND METHODS: The patients were randomly assigned to receive 63 Gy in 1.8 Gy fractions 7-days-a-week given over a period of 5 weeks (n=88), or 63 Gy in 1.8 Gy fractions given 5-days-a-week over 7 weeks (n=87). It represents 65% of an overall trial size. Acute mucosal reactions were scored using modified Dische system. Polychotomous logistic regression was used to estimate the influence of the selected variables on maximum grade of mucositis, and percent of the body weight loss during radiotherapy. RESULTS: The average maximum Dische score and percent of the patients with confluent mucositis were higher in patients treated with p-CAIR, compared to p-CF (13.3 vs. 10.8 and 54 vs. 27%). Polychotomous logistic regression analysis revealed that fractionation scheme and tumour site have significantly influenced maximum Dische score. Tumour site (laryngeal vs. other) had even stronger influence on maximum Dische score than fractionation scheme. The average residual Dische score 8 weeks after radiotherapy was higher in p-CAIR compared to p-CF (2.1 vs. 1.4), and was, most frequently, related to persistent mucosal erythema (70 vs. 57% of pts.). No severe consequential toxicity of radiotherapy was observed, so far, in the trial. CONCLUSIONS: While the incidence, intensity and duration of mucosal reactions was higher in p-CAIR than in p-CF the accelerated treatment can be considered tolerable with respect to acute toxicity. In both arms of the trial slight or moderate mucosal erythema was the most frequent acute side effect, which did not completely subside within 8 weeks after irradiation.

Acute Disease↗

PubMed2004

Clinical radiobiology of stage T2-T3 bladder cancer.

PURPOSE: To evaluate the relationship between total radiation dose and overall treatment time (OTT) with the treatment outcome, with adjustment for selected clinical factors, in patients with Stage T2-T3 bladder cancer treated with curative radiotherapy (RT). METHODS AND MATERIALS: The analysis was based on 480 patients with Stage T2-T3 bladder cancer who were treated at the Center of Oncology in Gliwice between 1975 and 1995. The mean total radiation dose was 65.5 Gy, and the mean OTT was 51 days. In 261 patients (54%), planned and unplanned gaps occurred during RT. Four fractionation schedules were used: (1) conventional fractionation (once daily, 1.8-2.5 Gy/fraction); (2) protracted fractionation (pelvic RT, once daily, 1.6-1.7 Gy/fraction, boost RT, once daily, 2.0 Gy/fraction); (3) accelerated hyperfractionated boost (pelvic RT, once daily, 2.0 Gy/fraction; boost RT, twice daily, 1.3-1.4 Gy/fraction); and (4) accelerated hyperfractionation (pelvic and boost RT, twice daily, 1.2-1.5 Gy/fraction). In all fractionation schedules, the total radiation dose was similar (average 65.5 Gy), but the OTT was different (mean 53 days for conventional fractionation, 62 days for protracted fractionation, 45 days for accelerated hyperfractionated boost, and 41 days for accelerated hyperfractionation). A Cox proportional hazard model and maximum likelihood logistic model were used to evaluate the relationship between the treatment-related parameters (total radiation dose, dose per fraction, and OTT) and clinical factors (clinical T stage, hemoglobin level and bladder capacity before RT) and treatment outcome. RESULTS: With a median follow-up of 76 months, the actuarial 5-year local control rate was 47%, and the overall survival rate was 40%. The logistic analysis, which included the total dose, OTT, and T stage, revealed that all of these factors were significantly related to tumor control probability (p = 0.021 for total radiation dose, p = 0.038 for OTT, and p = 0.00068 for T stage). A multivariate Cox model, which included the treatment-related parameters and other clinical factors, revealed that the hemoglobin level and bladder capacity before RT and T-stage were statistically significant factors determining local control and overall survival. The total radiation dose was of borderline statistical significance for overall survival (p = 0.087), and OTT did not reach statistical significance. CONCLUSION: The results of our study showed that the treatment outcome after RT for bladder cancer depends mainly on clinical factors: hemoglobin level and bladder capacity before RT, and clinical T stage. An increase in the total radiation dose seemed to be associated with a better treatment outcome. The effect of the OTT was difficult to define, because it was influenced by other prognostic factors.

Adult↗

PubMed2004

Pitfalls in IMRT treatment planning with the CadPlan-Helios system.

The CadPlan-Helios treatment planning system for intensity-modulated radiation therapy (IMRT) includes some physical parameters that are specified by the planner, and thus can be subjectively interpreted. The choice of the value of these parameters strongly depends on the practical experience of the planner. This paper presents some extremes of the optimization constraints, to illustrate some traps of IMRT planning. The examples used in this paper are not directly related to clinical situations and some problems were deliberately exaggerated. Treatment fields were defined as recommended by Memorial Sloan-Kettering Cancer Center procedures for prostate IMRT. Prostate plans were arranged using a 5-field technique and 20-MV photon beam. The target and critical structures were defined and contoured for CadPlan-Helios. All computer calculations were performed for the same field arrangement. The following optimization parameters and factors are presented and analyzed in examples to visualize the importance of each parameter: dose-volume constraints and priority factors, scatter distance, maximum number of iterations and termination tolerance. The presented analysis strongly suggests that all constraints and parameters should be recorded in individual planning charts because without their nominal values, any reanalysis or dose recalculation may be difficult.

Clinical Competence↗

PubMed2004

Training logbook for radiotherapy.

AIM: To develop a structured logbook for trainees in the medical specialty of radiotherapy with Europe that records the increasing experience throughout their training period. MATERIAL AND METHODS: A working party appointed by the European Board of Radiotherapy developed a draft version of a European logbook for trainees in radiotherapy. For development, the update European Core Curriculum for Radiotherapists (Radiation Oncologists) was taken into consideration. The logbook is composed of six sections: (1) biodata of the trainee, (2) scientific training documentation, (3) clinical training documentation, (4) record of formal presentations by the trainee, (5) publications, (6) training courses. Decisions were made to suggest that the clinical section of the logbook should: (a) only collect data that was essential for the purposes of appraisal, assessment and regulation, (b) be as user friendly as possible, (c) concentrate on quality of the data and not volume. The logbook was tested by trainees in several European training departments and adapted according to their suggestions. A final draft of the logbook was circulated among the national and professional societies for radiotherapy in Europe for review before a European consensus conference took place in Brussels in December 2002. RESULTS: The European training logbook for radiotherapy was endorsed by representatives of 35 European nations during the Brussels consensus conference on December 14, 2002. CONCLUSION: Keeping a training logbook is an essential feature of the record of training for all EU trainees who wish to retain an opportunity to spend part of their training time in another country of the Union, important for someone who seeks an appointment as a specialist in another country within a few years of achieving specialist accreditation, and good professional practice for all other trainees. The European training logbook for radiotherapy is a robust instrument that allows the systematic collection of the information that needs to be recorded to monitor the professional development of European trainees in Radiation Oncology.

Clinical Competence↗

PubMed2003

1H-MR spectroscopy of normal brain tissue before and after postoperative radiotherapy because of primary brain tumors.

PURPOSE: Brain metabolism after surgery and postoperative radiotherapy (pRT) because of primary brain tumors was assessed by proton magnetic resonance spectroscopy ((1)H-MRS) in vivo. The study was designed to reveal the impact of pRT on normal brain tissue metabolism, which may potentially help in delineating the target volumes for reirradiated patients. METHODS AND MATERIALS: Spectra of 43 patients ages 16-63 years treated with pRT for primary glial tumors in the Center of Oncology Maria Curie Memorial Institute Branch in Gliwice were analyzed. The control group consisted of spectra acquired for 30 healthy volunteers. All patients were treated with 3D conformal techniques using 6-20 MV photons to total doses of 60 Gy. Spectra were acquired from the control region before pRT and from three uninvolved regions 9-12 months after the end of pRT. Voxels were located in the region of low (<6 Gy), medium (29-39 Gy), and high radiation dose ( approximately 60 Gy). Relative intensities of the signals relating to N-acetyl-aspartate (NAA), choline-based compounds, creatine and phosphocreatine (Cr), mio-Inositol, lactate, and lipids were obtained. RESULTS: The spectra of "normal brain" taken 9 months after pRT are significantly different from those obtained for control volunteers and from the spectra acquired before radiotherapy. The lactate and lipids signals are very strong; however, they are not correlated with absorbed dose. NAA/Cr ratios are significantly lower than before radiotherapy even for the low-dose regions. Differences increase with radiation dose: the NAA/Cr ratio is significantly lower for the regions of brain receiving a high dose of radiation than for the low-dose areas. CONCLUSION: Combined treatment of primary brain tumors (surgery + postoperative radiotherapy) causes alteration of brain metabolism, even in regions of the brain far from the postoperative tumor bed and receiving relatively low total doses of radiation. Single voxel MRS spectroscopy in vivo cannot help in delineating target volumes for secondary irradiation.

Adolescent↗

PubMed2003

Time factor in postoperative radiotherapy: a multivariate locoregional control analysis in 868 patients.

PURPOSE: To study locoregional tumor control in postoperative radiotherapy (PRT) for head-and-neck cancer in relation to the position and duration of treatment gaps, duration of the interval surgery-radiotherapy, and to the other potentially prognostic variables. METHODS AND MATERIALS: The retrospective study included 868 patients with cancer of the larynx, oral cavity, oropharynx, and hypopharynx treated in Gliwice between 1980 and 1997. Mean total radiation dose, dose per fraction, overall radiation treatment time (OTT), and the interval surgery-PRT were 62.8 Gy, 2.1 Gy, 45 days, and 63 days, respectively. No interruptions during PRT (except for weekend breaks) appeared in 30% of patients, whereas 19% had more than 5 days of gap. The actuarial locoregional recurrence-free survival (RFS) has been examined using multivariate Cox regression model, and the ultimate locoregional tumor control probability using a logistic model. RESULTS: Increased duration of treatment gaps, positive resection margins, pathologically proven metastases to the neck nodes, and extralaryngeal site of cancer were significantly related to a decrease in RFS. The duration of time interval surgery-PRT appeared, by contrast, only borderline significant for RFS. The relative risk of locoregional recurrence was approximately the same for the gaps in days 1-21 as for the "late" gaps (days >21), except in a subgroup of patients with positive clinical margins. The logistic analysis revealed a significant time-related displacement of the dose-response curves for PRT. The detriment from the protraction of OTT appeared to be larger than the benefit from the equivalent shortening of OTT. CONCLUSIONS: Although the conclusions from this study must be regarded as only hypothesis-generating, we assume that a highly significant adverse influence of radiation treatment gaps on the rate of tumor control is consistent with rapid repopulation of cancer clonogenes during PRT. Lack of significant effect of the position of gaps on locoregional tumor control after radical surgery may suggest that a lag time for the onset of repopulation in PRT is short. A less likely explanation is that the total amount of regeneration during OTT is the same, regardless of the timing of the gap, even if all the repopulation occurred late. The magnitude of the detriment in tumor control from prolonged interval surgery-PRT indicates that repopulation of cancer cells between surgery and radiotherapy is not as fast as between the fractions of radiotherapy.

Adult↗

PubMed2002

How fast is repopulation of tumor cells during the treatment gap?

PURPOSE/OBJECTIVE: Our goal was to analyze the repopulation of surviving tumor cells during a treatment gap in radiotherapy for head-and-neck cancer. METHODS AND MATERIALS: Clinical material is based on the records of 1502 patients treated by radiotherapy alone in Maria Sklodowska-Curie Memorial Institute in Gliwice during the period between1980 and 1989. All patients had histologically confirmed squamous cell carcinoma of the larynx or pharynx. The mean gap duration was 9 days. Only 10% of patients were treated without gaps. The dose per fraction was in the range of 1.5 to 2.5 Gy. Patient data were fitted directly to the mixed linear-quadratic model using maximum-likelihood estimation. Tumor stage or tumor localization was introduced into the equation as a categorical variable. Tumor proliferation was estimated by dividing the treatment gaps into three groups: the first 2 weeks, second 2 weeks, and the period after 4 weeks of irradiation. RESULTS: Tumor control probability was significantly correlated with radiation dose, tumor progression (according to TNM), overall treatment time, and gap duration. Laryngeal cancers had a better prognosis than cancers of the oro- and nasopharynx. Significant tumor repopulation was found after the first 2 weeks of radiotherapy. During the treatment gap, the proliferation rate was equal to 0.75 Gy/day. During the days with irradiation, repopulation was slower and equal to 0.2 Gy/day. CONCLUSION: The repopulation of tumor cells is faster during a gap than during the normal days of irradiation. Accelerated repopulation probably starts soon after 2 weeks of irradiation.

Cell Division↗

PubMed2002

1H-MRS in vivo predicts the early treatment outcome of postoperative radiotherapy for malignant gliomas.

PURPOSE: To analyze prospectively the prognostic significance of 1H magnetic resonance spectroscopy (MRS) in vivo recorded from the tumor bed of patients after surgery for malignant glioma. METHODS AND MATERIALS: Fifty-one patients aged 20-68 years were examined using a MRI/MRS system (Elscint 2T Prestige). Of the 51 patients, 33 had Grade 3 gliomas and 18 had glioblastomas. MRI-localized 1HMR spectra were acquired using a single-voxel, double-spin-echo sequence. Relative intensities of the signals (choline, creatine [Cr] N-acetyl aspartate [NAA], myo-inositol, lactate, and lipids) were obtained by numeric integration of fitted signals. Two voxels were examined, one located at the tumor bed and the second distant to the tumor bed. All patients were irradiated to 60 Gy using three-dimensional conformal noncoplanar techniques to 60 Gy. RESULTS: MRS in vivo in patients after brain tumor surgery revealed a statistically significant decrease in the NAA/Cr ratio and increases in the choline/creatine (Cr), choline/NAA, and myo-inosytol/Cr ratios. The intensive signals of lactate and lipids appeared in spectrum. Survival correlated strongly with tumor grade and patient age but the strongest prognostic factor was the lactate/NAA ratio. For lactate/NAA values >2.0 (intensive lactate signal) the 1-year survival rate was 20%, and for lactate/NAA values <2.0, the 1-year survival rate was 85%. CONCLUSION: A new diagnostic tool demonstrated ability to distinguish between patients with a favorable prognosis and those who will die within 1 year.

Adult↗