Adaptive off-line protocol for prostate external radiotherapy with cone beam computer tomography.

PURPOSE: The goal of this work was to prepare and to evaluate an off-line adaptive protocol for prostate teleradiotherapy with kilovoltage cone beam computer tomography (CBCT). PATIENTS AND METHODS: Ten patients with localized prostate carcinoma treated with external beams underwent image-guided radiotherapy. In total, 162 CBCT images were collected. Position of prostate and pubis symphysis (PS) with respect to the isocenter were measured off-line. Using the CBCT scans obtained in the first three fractions the average position of prostate in relation (AvPosPr) to PB was calculated. On each CBCT scan, the position of prostate with respect to AvPosPr was calculated and cumulative histogram of prostate displacement with respect to AvPosPr was prepared. Using this data, the adaptive protocol was prepared in which (1) based on the CBCT made in the first three fractions the AvPosPr to PS is obtained, (2) in all other fractions two orthogonal images are acquired and if for any direction set-up error exceeds 0.2 cm the patient's position is corrected, and (3) additionally, the patient's position is corrected if the AvPosPr exceeds 0.2 cm in any direction. To evaluate the adaptive protocol for 30 consecutive patients, the CBCT was also made in 10th and 21st fraction. RESULTS: For the first 10 patients, the results revealed that the prostate was displaced in relation to AvPosPr >0.7 cm in the vertical and longitudinal directions only on 4 and 5 images of 162 CBCT images, respectively. For the lateral direction, this displacement was >0.3 cm in one case. For the group of 30 patients, displacement was never >0.7, and 0.3 cm for the vertical and lateral directions. In two cases, displacements were >0.7 cm for the longitudinal direction. CONCLUSION: Implementation of the proposed adaptive procedure based on the on-line set-up error elimination followed by a reduction of systematic internal error enables reducing the CTV-PTV margin to 0.7, 0.7, and 0.4 cm for the vertical, longitudinal, and lateral directions, respectively.

Sphincter preservation following preoperative radiotherapy for rectal cancer: report of a randomised trial comparing short-term radiotherapy vs. conventionally fractionated radiochemotherapy.

BACKGROUND AND PURPOSE: The aim was to verify whether preoperative conventionally fractionated chemoradiation offers an advantage in sphincter preservation in comparison with preoperative short-term irradiation. PATIENTS AND METHODS: Patients with resectable T3-4 rectal carcinoma without sphincters' infiltration and with a lesion accessible to digital rectal examination were randomised into: preoperative 5x5Gy short-term irradiation with subsequent total mesorectal excision (TME) performed within 7 days or chemoradiation to a total dose of 50.4Gy (1.8Gy per fraction) concomitantly with two courses of bolus 5-fluorouracil and leucovorin followed by TME after 4-6 weeks. Surgeons were obliged to base the type of operation on the tumour status at the time of surgery. RESULTS: Between 1999 and 2002, 316 patients from 19 institutions were enrolled. The sphincter preservation rate was 61% in the 5x5Gy arm and 58% in the radiochemotherapy arm, P = 0.57. The tumour was on average 1.9 cm smaller (P < 0.001) among patients treated with chemoradiation compared with short-term schedule. For patients who underwent sphincter-preserving procedure, the surgeons generally followed the rule of tailoring the resection according to tumour downsizing; the median distal bowel margin was identical (2 cm) for both randomised groups. However, in the chemoradiation group, five patients underwent abdominoperineal resection despite clinical complete response. CONCLUSIONS: Despite significant downsizing, chemoradiation did not result in increased sphincter preservation rate in comparison with short-term preoperative radiotherapy. The surgeons' decisions were subjective and based on pre-treatment tumour volume at least in clinical complete responders.

A multicentre randomized/controlled trial of a conventional versus modestly accelerated radiotherapy in the laryngeal cancer: influence of a 1 week shortening overall time.

BACKGROUND AND PURPOSE: To compare in a phase III study the loco-regional control, disease-free survival and overall survival induced by an accelerated regimen (AF) as compared with conventional regimen (CF) and to analyze the early and late post-radiation morbidity in both arms. MATERIALS AND METHODS: Patients with age < or = 75, WHO 0-1, suitable for a radical course of radiotherapy T1-T3, N0, M0, stage of glottic and supraglottic laryngeal cancer were randomized to either CF: 66Gy given in 33 fractions over 45 days or AF: 66Gy given in 33 fractions over 38 days (2 fractions every Thursday). A total of 395 patients were included from 05.1995 to 12.1998. RESULTS: Early toxicity: At the end of radiotherapy patients treated with AF complained for more severe reactions than patients treated with CF. In 8 weeks after treatment completion patients treated with AF complained only for more severe pain on swallowing (P=0.027). In 4 months after treatment completion all types of toxicity except for skin teleangiectasia (P=0.001) were similar in the two groups. Loco-regional control: comparison between CF and AF showed no difference in terms of loco-regional control (P=0.37). CONCLUSIONS: The improvement in AF in terms of loco-regional control is estimated to be 3-5% in comparison with conventional regimen and is not significant. The intensity of reactions after 4 months was similar in both arms, what suggests the possibility of further shortening of the overall time by few days or enhancing the total dose within the limits of acceptable morbidity.

Comparison between dose values specified at the ICRU reference point and the mean dose to the planning target volume.

BACKGROUND AND PURPOSE: To compare dose values specified at the reference point, as recommended by the International Commission on Radiation Units and Measurements, ICRU, and the mean dose to the planning target volume, PTV. MATERIAL AND METHODS: CT-based dose calculations were performed with a 3-D treatment planning system for 6 series of patients treated for bladder, brain, breast, lung, oropharynx and parotid gland tumour. All patients were arbitrarily chosen from a set of previously treated patients irradiated with a two- or three-field technique using customised blocks. Appropriate wedge angles and beam weights were chosen to make the dose distribution as homogeneous as possible. RESULTS: The dose at the ICRU reference point was generally higher than the mean dose to the PTV. The difference between the ICRU reference dose and the mean dose to the PTV for an individual patient was less than 3% in 88% of cases and less than 2% in 72% of the cases. The differences were larger in those patients where the dose distribution is significantly influenced by the presence of lungs or air gaps. For each series of patients the mean difference between the ICRU reference dose and the mean dose to the PTV was calculated. The difference between these two values never exceeded 2%. Because not all planning systems are able to calculate the mean dose to the PTV, the concept of the mean central dose, the mean of the dose values at the centre of the PTV in each CT slice, has been introduced. The mean central dose was also calculated for the same patients and was closer to the mean dose to the PTV than the ICRU reference dose. CONCLUSION: The mean dose to the PTV is well estimated by either the ICRU reference dose or the mean central dose for a variety of treatment techniques for common types of cancer.

[Results of 3-stage treatment: (I) corticotherapy, (II) linear acceleration and (III) orbital decompression in 206 patients with malignant Graves ophthalmopathy]. / Wyniki 3-etapowego leczenia: (I) kortykoterapia, (II) akcelerator liniowy i (III) dekompresja oczodlów, 206 chorych z wytrezeszczem zlosliwym w chorobie Graves-Basedowa.

There is no, so far, a rational method of therapy based upon the etiology of autoimmune Graves' ophthalmopathy. As a malignant Graves' ophthalmopathy we defined the most severe eye changes leading to the sight loss or permanent disability of vision which are classified as exceeded class 3c according to the eye changes classification of the American Thyroid Association [27]. The aim of the study was to develop the most efficacious method of therapy for malignant Graves' ophthalmopathy. The material consisted of 206 patients treated according to the 3-stage method: 1-st--corticotherapy, 2-nd--radiotherapy, including linear accelerator, 3-rd--orbital decompression. Moreover, in four patients plasmapheresis was applied and in additional five cyclosporine was administered. In all 206 patients the estimation of the results of the treatment was based on the Donaldson ophthalmopathy index [4]. It has been proved that corticotherapy combined with linear accelerator radiotherapy has been the most efficacious method of treatment. It has also the least number of side effects. Orbital decompression as the 3-rd stage of treatment was employed in those cases in which the previous two stages of medical therapy were unsuccessful.

[Our first experience with allogeneic and autologous transplantation of hematopoietic stem cells]. / Pierwsze wlasne doswiadczenia z allo- i autotransplantacja krwiotwórczych komórek macierzystych.

The main problems and difficulties in transplantation of haematogenous stem cells are discussed. The problems include: organization of a team of specialists and bone marrow transplantation centre, preparation of the recipient (patient) complications connected with preparation for transplantation, graft taking, graft versus host disease, recurrence of the underlying disease. In the analysis only those patients (8 cases) are included who had received marrow transplantation after chemotherapeutic-radiotherapeutic preparation (3 patients are alive). The first experiences are described also with three autotransplantations of haematogenous stem cells obtained by means of cell separator from peripheral blood. These experiences indicate that it is possible in our country to carry out this highly sophisticated method which requires, however, further improvements and ensuring of adequate personnel and equipment.

[Technique for postoperative irradiation of patients with breast cancer using electron and cobalt beams]. / Technika napromieniania chorych na raka sutka wiazkami elektronów i promieniami gamma Co 60.

The method of chest wall and mammary lymph node irradiation using obliquely incident electron beams is presented. Dose distributions measured in Rando phantom and calculated by computer programme are discussed. The conditions for geting homogenous dose distribution within the target volume are given. The use of this technique is limited by the degree of curvature of the chest wall and depth of tumour volume where maximum obliquity occurs. In order to minimize the lung irradiation the use of compensating boluses is recommended.