Tomasz Piotrowski

The repeated use of high dose rate brachytherapy for locally recurrent lung cancer

Summary Purpose To assess the effect of repeated palliative treatment with high dose rate brachytherapy in patients with advanced lung cancer. Material and Methods Fifty-six patients, 25.3% of a total of 221 patients treated for lung cancer with HDR brachytherapy were treated twice, using High Dose Rate Brachytherapy. All patients were qualified for repeated brachytherapy due to the recurrence of intrabronchial tumour and acceptable remissions after the first treatment. The survival times were compared with selected clinical data. Correlations between survival times and subjective breathing difficulties were analyzed separately. Results The median survival time in the whole group of patients was 8.9 months. The period of obtaining a positive clinical response was correlated with a longer survival time (log-rank test, p=0.0009, F Cox test, p=0.007). In the multivariate analysis other statistically important prognostic factors were also included: the clinical stage of the primary tumour (F Cox test, p=0.04), and the interval between the first and second treatment (F Cox, p=0.004). None of the analyzed factors (dyspnoea, cough, haemoptysis and pain) had any influence on survival. Conclusion Repeated HDR brachytherapy in advanced lung cancer was an efficient method that in many patients led to regression of symptoms and improvement in life quality.

Generation of predetermined isodose inclination with the use of a motor driven wedge filter

Summary Aim The aim of this work was to determine an algorithm to obtain a predetermined inclination angle of isodoses for the Saturn 43F linear accelerator with the use of a motor driven wedge filter. Materials/Methods It was assumed that a predetermined inclination angle of a reference isodose could be obtained after combining absorbed doses during irradiation with an open field and with a field with a constant 60° wedge. In order to find relations between isodose angles and the irradiation time doses were measured first in a plexiglas phantom and then in a water phantom at the reference depth for the combination of an open field and a field with a 60° wedge. The doses measured under the wedge were normalized with use of the 60° wedge coefficients and converted using tabulated values of the percent depth doses into depth values. Then the angles of isodose slope were calculated. Results The results are presented in tables and in figures. The polynomials used to calculate times t 0 and t 60 for predetermined isodose angles were obtained. Conclusions The polynomials obtained differ from energy to energy. The differences in isodose inclination angles increase with irradiation time using a 60° wedge. The higher is the energy of the beam, the greater is the inclination of the isodoses using the same physical wedge. The differences between the results of measurements in a solid phantom and in a water phantom are due to the differences in depth dose distributions between both materials.

337. Effect of palliative treatment with High Dose Rate intraluminal brachytherapy on survival in patients with advanced oesophageal cancer

Purpose The aim of this work was to analyse results of palliative HDR brachytherapy in patients with advanced esophageal cancer. Material and methods Nighty-one patients with unresectable, advanced esophageal cancer were treated palliatively by HDR brachytherapy. All patients received total dose of 22.5 Gy in three fractions every week. Remissions of dysphagia and other clinical and radiological factors were assessed in 1st month after the end of treatment, and then in 3d, 6th and 12th months. Survival rate was compared with choosen clinical factors using log-rank test and Kaplan Meier method. Results Median survival time in whole group of patients was 8.2 months. Median survival time according to received remission was, respectively – for CR – 14.6 months, for PR – 7.2 months, for NR – 3.8 months (Iog-rank p=00001, F Cox p= 0.00001). Longer median survival time we observed when tumor length was below 5 cm (12.1 months) then between 5 and 10 cm (7.8 months) or longer then 10 cm (6.4 months) (log-rank p=0.002). Longer median survival time we observed in clinical stage II (14.1 months) compared with clinical stage III (7.7 months) and IV (7.2 months) (log-rank p=0.01). Significant correlations were found between survival and Karnofsky performance status, grade of dysphagia and age. Conclusions Grade of remission assessed in 1st month after the end of treatment, age of patients and grade of dysphagia had influence on survival (confirmed in multivariate analysis). In univariate analysis important prognostic factors were also: Karnofsky performance status, clinical stage, length of tumour.

HIGH DOSE RATE ENDOBRONCHIAL BRACHYTHERAPY IN THE MANAGEMENT OF ADVANCED LUNG CANCER - COMPARISON OF DIFFERENT DOSES - PRELIMINARY ASSESSMENT

Purpose: Brachytherapy is one of the most efficient methods of overcoming endobronchial obstruction in palliative treatment of lung cancer. In single cases, brachytherapy is performed as radical treatment, however in most of cases, due to advanced clinical stage it has a palliative aim. In the absence of clear consensus regarding the value of doses used in brachytherapy different fraction doses are used in clinical treatment. The aim of this work is to compare results of palliative high dose rate brachytherapy using various treatment protocols with the view to analysing differences in survival and diminishing breathing difficulties. Material and methods: Between May 1999 and February 2000 at the Greatpoland Cancer Center, 69 patients with advanced lung cancer were treated by high dose rate brachytherapy. They were disqualified from radical treatment due to advanced clinical stage. The age of the patients ranged from 39 to 76 years (average 53,2 years). Fifty-one patients received a total dose of 22,5 Gy in 3 fractions once a week, 18 patients received one single fraction of 10 Gy. All the patients were divided into two groups according to their clinical stage and the Karnofsky score – those with the Karnofsky score lower than 50 were qualified for a single fraction treatment. They were under clinical and endobronchial observation as regards survival rates, local remission and subsiding dyspnoea, breathing, cough and haemoptysis in the first, third, sixth and twelveth month of observation. Results: Four weeks after the end of treatment subjective improvement (subsidence of all symptoms) was ascertained in 61/69 (88,4%) patients. In 12 cases (17,4%) complete remission (CR), in 49 cases (71,0%) - partial remission (PR) of the tumor were found. During one year of observation 45 (65,2%) patients died, in 10 cases (14,5%) improvement of in dyspnoea was observed and in 14 cases (20,3%) recurrence and progression of the disease were noted. There was no statistical difference in the survival rates between the two groups of patients treated with different fractions protocols. Conclusions: 1. Brachytherapy in advanced lung cancer is an efficient method that led in most of patients to subcidence of symptoms and to improvement of the quality their lives. 2. The two treatment protocols showed similar efficiency in overcoming difficulties in breathing. 3. Survival rates were similar in both group of patients treated with different treatment protocols.

71. The results of postoperative radiotherapy in 63 patients with low-grade gliomas treated in Greatpoland Cancer Center

Introduction Low-grade glicomas represents 15% of all primary brain tumors. Material and Method Between 1990–97 63 patient with low-grade gliomas were treated in Greatpoland Cancer Center (39 males, 24 females; age between 20–60 year). 15 patients had andegrone complete surgical excision, 48 partial or subtotal excision of tumor. The frontal lobe was affected in 33 patients, the temporal lobe in 14 patients. Patients received conventional irradiaton of 60 Gy. Results * Five patients with histologically verified pilocytic astrocytomas(I) were treated after partial excision, median of age 29.2 year median survival 58 months (27–108). Only one patient died 27 months after radiotherapy. * Thirteen patients with fibrylar astrocytomas(II)-11 post subtotal excision-median age 37.7 year median survival 32.5 months. Recurrent tumor in two patients. Five patients are alive. * Ten patients with protoplasmatic astrocytoma(II)-7 post subtotal excision median of age 43.5 year median survival 30.8 months. Four patients alive. * Seven patients with gemistocytic astrocytomas(II) (6 post subtotal excision)-median age 36 year, median survival 32 months. Only one patient alive. * Eleven patients with oligoastrocytomas(II)-11 post subtotal excision, median age 38.6 year, median survival 43.9 months. Two patients with recrrent tumor. Alive 8 patients. * Seventeen patients with oligodendrogliomas (11 post subtotal excision) median age 39 years, median survival 39 months. One patien with recrrent tumor. Alive 8 patients. Conclusions * 30 patients are alive(48%); * histopathologic diagnosis pilocytic astrocytomas asociated with age 10 years younger then either low-grade gliomas and long-term survivors; * poor prognistic factor in gemistocytic astrocytomas-only one patient alive; * five patients with recurrent tumor among 17 to 49 months after radiotheraphy.

28 Brachyterapia HDR w leczeniu nieoperacyjnego raka przełyku

Wstep Chorzy zdyskwalifikowani od zabiegu operacyjnego z powodu umiejscowienia oraz zaawansowania klinicznego raka przelyku są grupą o zlym rokowaniu. Nieliczni mogą byc zakwalifikowani do radykalnej teleterapii, wiekszośc chorych jest leczona objawowo. W pracy przedstawiono wstepne wyniki brachyterapii HDR chorych na nieoperacyjnego raka przetyku. Material i metody W okresie od maja 1999 do lutego 2000 poddano brachyterapii HDR w Wielkopolskim Centrum Onkologii 37 chorych na nieoperacyjnego raka przelyku. Wiek chorych siegal od 42 do 81 lat, średnio 53,1 lat. W brachyterapii HDR stosowano najcześciej dawke 21,5 Gy na guz w trzech frakcjach, w 5 przypadkach dodatkowo napromieniono środpiersie dawką 20 Gy w 5 frakcjach. U 5 chorych leczonych radykalnie zastosowano po brachyterapii teleterapie w dawce od 50 do 60 Gy na okolice przelyku. Oceniono wplyw stosowanego leczenia na uzyskanie remisji miejscowej oraz ustepowanie dysfagii w 1, 3 i 6 miesiącu po zakonczeniu leczenia. Wyniki Średni okres obserwacji wynosil 6 miesiecy. Remisje calkowitą ocenianą w 1 miesiącu po zakonczeniu leczenia stwierdzono u 4 chorych (10,8%), cześciową u 25 chorych (67,6%), brak remisji u 8 chorych (21,6%). Po 3 i 6 miesiącach remisja utrzymywata sie u 2/3 chorych pozostających w obserwacji. W grupie chorych leczonych metodą skojarzoną remisje catkowitą stwierdzono u 2 chorych (20%), cześciową u 6 chorych (60%). U 4 chorych (10,8%) w trakcie badan kontrolnych wykryto przetoke. Wnioski Brachyterapia HDR wplynela na ustepowanie dysfagii u znacznej cześci chorych na nieoperacyjnego raka przelyku. U niektorych chorych uzyskano calkowitą remisje utrzymującą sie dluzej niz pol roku. Tolerancja leczenia byla dobra, a odsetki powiklan nie odbiegaly od uzyskanych przez innych autorow.