Biomedical subjects

M Schlienger

Publications and source records attributed to M Schlienger.

At least 19 recordsLinked to original sources

PubMed2006

[Epidermoid carcinomas of anal canal treated with radiation therapy and concomitant chemotherapy (5-fluorouracil and cisplatin)].

PURPOSE: To evaluate our results after radiation therapy and concomitant chemotherapy in terms of local control, survival and toxicity in patients with anal cancer. METHODS AND PATIENTS: Between November 1990 and January 2002, 60 patients (pts) were treated with radiation therapy and concomitant chemotherapy. The T-stage according to the 2001 UICC classification were: 2 T1, 26 T2, 25 T3, and 7 T4. There were 20 pts with nodal involvement at presentation. The treatment started with external beam RT (median dose: 45 Gy) and concomitant chemotherapy using 5-fluorouracil and cisplatin during the first week and the fifth week of external beam RT (EBRT). After a rest period of 4 to 6 weeks, a boost of 20 Gy was delivered by EBRT in 58 pts and by interstitial (192)Ir brachytherapy in 2 pts. Mean follow-up were 78.5 months. RESULTS: At the end of RT with concomitant chemotherapy local tumor clinical complete response rate was 83%. Out of 10 non responders or local progression, 5 (50%) were salvaged with abdominoperineal resection (APR). Out of 5 local tumor relapses, 3 were salvaged with APR. The overall local tumor control (LC) rate with or without salvage local treatment were 88%. LC rate with a good anal function scoring (score 0 and 1) was 70%. Among 43 pts who preserved their anus, 98% had a good anal function scoring. The 5-year disease-free survival was 75%. After multivariate analysis, 2 independent predicting factors significantly influenced the disease-free survival: HIV-positive pts (negative vs positive, P=0.032) and clinical tumor response after the first course of radiotherapy (<50% vs >or=50%, P=0.00032). Acute grade 2 or 3 toxicities were low: haematological toxicity in 4 pts and intestinal complication corresponding to diarrhea in 10 pts. Late severe complication was observed in 3 pts: 2 pts with painful necrosis of the anus requiring colostomy and 1 pt with grade 3 rectal bleeding. CONCLUSION: We confirm the good results with RT and concomitant chemotherapy. The clinical tumor response after the first course of RT and concomitant chemotherapy is probably the most important predictive factor on the disease-free survival. For patients with T3 or T4 lesion and tumor regression <or=50% after the first course of radiation therapy, surgical non conservative treatment should be discussed.

Adult↗

PubMed2005

[Delay to radiotherapy: a study of three tumour sites].

In the following review of the literature, the reasons and consequences of a tendency to the increase of the delay between the diagnosis and the first irradiation session will be studied. The duration of the delay varies according to the protocol of treatment, which itself depends on the tumour. Moreover, all types of radiotherapy are concerned by the increase in delay. A retrospective study enables to determine for a given series of similar tumours and treatments the mean duration of delay and find the excessive duration. The increase of delay phenomenon exists in different countries. We know that before irradiation the tumour grows according to its biological characteristics and the TNM initial determination will no longer be true. On the other hand, effective treatments such as chemotherapy and hormone therapy are increasingly used alone, before or in combination with radiotherapy. Consequently, the classical timing of radiation therapy could be modified often delayed. It is difficult to consider that successive treatments are a real increase of delay and compare its results with previous data from radiotherapy alone. We will study its impact in three types of tumours, including tumours of head and neck, of the breast and prostate, which are the most widely reported. The consequences of prolonged delay are not easily evaluated: one of the more important parameters is the possible modification of the stage of tumour. This phenomenon is not restricted to the studied types of tumours. We will try to find possible ways of reducing abnormal delays before irradiation.

Breast Neoplasms↗

PubMed2005

[Results of the Sainte-Anne - Lyons series of 318 oligodendroglioma in adults].

INTRODUCTION: Incidence of cerebral oligodendrogliomas is increasing because of better recognition made possible by improved classifications. We studied a homogeneous series using the Sainte-Anne grading scale in order to better understanding the history of these tumors with or without treatment and to assess prognosis and associated factors. PATIENTS AND METHODS: A retrospective series of 318 adult patients with oligodendroglioma (OLG) treated at Hôpital Sainte-Anne, Paris (SA) and Hôpital Neurologique, Lyons (L) between 1984 and 2003 was analyzed: 182 grade A OLG (SA + L), 136 grade B among which a homogenous series of 98 (SA) were included. For grade A: age at diagnosis ranged from 21 to 70 (mean: 41), sex ratio was 1.28. For grade B: age at diagnosis ranged from 12 to 75 (mean: 45.5), sex-ratio was 1.58. The main first symptoms were: epilepsy (A: 91.5%; B: 76%), intracranial hypertension (A: 7.9%; B: 14.6%), neurological deficit (A: 5.1%; B: 17.7%). The most frequent locations were: frontal, insular and central for both A and B. Mean size was 55 mm for grade A, 62 mm for B. Calcifications were found in 20% of A, 48.5% of B. No tumor was enhanced on imaging (CT/MRI) in grade A, all but 7 in grade B. All patients underwent surgery either for biopsy (A: 47.2%; B: 53%), or removal which was partial (A: 26.4% vs B: 19.4%) or extended (A: 36.3% vs B: 37.8%). Fifty-six patients underwent 2 procedures and 12 three procedures. Radiotherapy was performed in 76.9% of grade A, and 91% of B patients, in the immediate postoperative period for 71% A and 82.7% B. Chemotherapy was delivered for 36% of grade A (in the event of transformation to grade B or failure of radiotherapy) and 67.5% of B patients. Among grade A tumors, 38% transformed into grade B within a mean delay of 51 months with a mean follow-up of 78 months. RESULTS: Median survival was 136 months for grade A and 52 for grade B. Survival at 5, 10 and 15 was 75.5%, 51% and 22.4% for grade A vs 45.2%, 31.3% and 0% for grade B respectively. In univariate and multivariate analysis, grade A survival was associated with age at diagnosis, tumor size, large removal and response to radiotherapy. Grade B survival was associated with age at diagnosis, wide removal and sharply defined limits of the tumor on imaging. CONCLUSIONS: Analysis of both published data and this series underlines many prognostic parameters. It shows that OLG are heterogeneous tumors even in each grade (A and B). Treatment should consequently progress towards more targeted procedures for patients mainly with postoperative radiotherapy and chemotherapy.

Adolescent↗

PubMed2003

[Epidermoid carcinomas of the anal canal treated with definitive radiation therapy in a series of 305 patients].

PURPOSE: To identify prognostic factors and treatment toxicity in a serie of epidermoid cancers of the anal canal without evident metastasis. PATIENTS AND METHODS: Between June 1972 and January 1997, 305 patients (pts) were treated with curative-intent radiation therapy (RT). The T-stages according to the 1987 UICC classification were: 26 T1, 141 T2, 104 T3, and 34 T4. There were 49 pts with nodal involvement at presentation. Pretreatment anal function scoring according to our in-house system was: 22 scored 0, 182 scored 1, 74 scored 2, 7 scored 3, 11 scored 4, and 9 not available pts. The treatment started with external beam RT (EBRT) in 303 pts (median dose: 45 Gy). After a rest period of 4 to 6 weeks, a boost of 20 Gy was delivered by EBRT in 279 pts and by interstitial 192Ir brachytherapy (Bcy) in 17 pts. Seven pts received only one course of EBRT (mean dose: 49.5 Gy) and 2 pts were treated with interstitial 192Ir Bcy alone (55 and 60 Gy, respectively). Concomitant chemotherapy (5-fluoro-uracil and either mitomycin C or cisplatin) was delivered to 19 pts. Mean follow-up was 103 months. RESULTS: At the end of RT local tumor clinical complete response (cCR) rate was 80%. Out of 61 non responders or local progressive tumors 27 (44%) were salvaged with abdominoperineal resection (APR). The rate of local tumor relapse (LR) was 12%. Out of 37 LTR, 20 (54%) were salvaged with APR and one with interstitial 192Ir Bcy. The orevall local tumor control (LC) rate with or without salvage local treatment was 84%. LC rate with a good anal function scoring (score 0 and 1) was 56.5%. Among 181/186 available pts who preserved their anus, 94% had a good anal function scoring. For a subgroup of 15 pts with length tumor <2 cm-N0, the LC rate after the end of RT was 100%, the LC rate with or without local salvage treatment was 100%, and among 13 available pts who preserved their anus, the anal function scoring was good in 12 pts (92%). The 10-years disease-free survival was 74%. After multivariate analysis, 3 independent predicting factors significantly influenced the disease-free survival: gap duration between 2 courses of RT (>38 days vs < or =38 days, P =0.0025), pretreatment anal function scoring (0 vs 1 vs 2 vs 3 vs 4, P =4.4 10(-6)), and cCR after the end of RT (no complete response vs complete response, P =2.5 10(-14)). CONCLUSION: We confirm excellent results with RT in T1 and T2 lesions. However, chemoradiotherapy should be prefered to improve survival free of colostomy with a good anal sphincter function for tumors more than or equal to 2 cm in length and locally advanced tumors.

Adult↗

PubMed2003

[Radiotherapy of carcinomas of the anal canal. Tenon Hospital experience].

Since 1980, curative-intent radiation therapy of epidermoid carcinoma of the anal canal is the standard first line treatment. The combined concomitant chemotherapy and radiation therapy is presently established for locally advanced tumors more than 4 cm in length and/or with nodal involvement. We report the Tenon hospital experience since 1972 concerning the long term results after radiation therapy, the modifications of the radiation technique, and the evolution of treatment strategy.

Aged↗

PubMed2001

Combination of photon and proton radiation therapy for chordomas and chondrosarcomas of the skull base: the Centre de Protonthérapie D'Orsay experience.

PURPOSE: Prospective analysis of local tumor control, survival, and treatment complications in 44 consecutive patients treated with fractionated photon and proton radiation for a chordoma or chondrosarcoma of the skull base. METHODS AND MATERIALS: Between December 1995 and December 1998, 45 patients with a median age of 55 years (14-85) were treated using a 201-MeV proton beam at the Centre de Protonthérapie d'Orsay, 34 for a chordoma and 11 for a chondrosarcoma. Irradiation combined high-energy photons and protons. Photons represented two-thirds of the total dose and protons one-third. The median total dose delivered within the gross tumor volume was 67 cobalt Gray equivalent (CGE) (range: 60-70). RESULTS: With a mean follow-up of 30.5 months (range: 2-56), the 3-year local control rates for chordomas and chondrosarcomas were 83.1% and 90%, respectively, and 3-year overall survival rates were 91% and 90%, respectively. Eight patients (18%) failed locally (7 within the clinical tumor volume and 1 unknown). Four patients died of tumor and 2 others of intercurrent disease. In univariate analysis, young age at time of radiotherapy influenced local control positively (p < 0.03), but not in multivariate analysis. Only 2 patients presented Grade 3 or 4 complications. CONCLUSION: In skull-base chordomas and chondrosarcomas, the combination of photons with a proton boost of one-third the total dose offers an excellent chance of cure at the price of an acceptable toxicity. These results should be confirmed with a longer follow-up.

Adolescent↗

PubMed2001

Adenocarcinoma of the endometrium treated with combined irradiation and surgery: study of 437 patients.

PURPOSE: To identify prognostic factors and treatment toxicity in a series of operable endometrial adenocarcinomas. METHODS AND MATERIALS: Between November 1971 and October 1992, 437 patients (pts) with endometrial carcinoma, staged according to the 1988 FIGO staging system (225 Stage IB, 107 Stage IC, 4 Stage IIA, 35 Stage IIB, 30 Stage IIIA, 6 Stage IIIB, and 30 Stage IIIC), underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy without (n = 140) or with (n = 297) pelvic lymph node dissection. The chronology of adjuvant RT was not randomized and depended on the usual practices of the surgical teams. Seventy-nine pts (Group I) received preoperative low-dose-rate uterovaginal brachytherapy (mean dose [MD]: 57 Gy). Three hundred fifty-eight pts (Group II) received postoperative RT. One hundred ninety-six pts received low-dose-rate vaginal brachytherapy alone (MD: 50 Gy). One hundred fifty-eight pts had external beam pelvic RT (MD: 46 Gy) followed by low-dose-rate vaginal brachytherapy (MD: 17 Gy). Four pts had external beam pelvic RT alone (MD: 47 Gy). The mean follow-up from the beginning of treatment was 128 months. RESULTS: The 10-year disease-free survival rate was 86%. From 57 recurrences, only 12 were isolated locoregional recurrences. The independent factors decreasing the probability of disease-free survival were as follows: histologic type (clear-cell carcinoma, p = 0.038), largest histologic tumor diameter >3 cm (p = 0.015), histologic grade (p = 0.008), myometrial invasion > 1/2 (p = 0.005), and 1988 FIGO staging system (p = 9.10(-8)). In Group II, the addition of external beam pelvic RT did not seem to independently improve vaginal or pelvic control. The postoperative complication rate was 7%. The independent factors increasing the risk of postoperative complications were stage FIGO (p = 0.02) and pelvic lymph node dissection (p = 0.011). The 10-year rate for Grade 3 and 4 late radiation complications according to the LENT-SOMA scoring system was 3.1%. External beam pelvic RT independently increased the rate for Grade 3 and 4 late complication (RR: 5.6, p = 0.0096). CONCLUSION: Postoperative external beam pelvic RT increases the risk of late radiation complications. After surgical and histopathologic staging with pelvic lymph node dissection, in subgroup of "intermediate-risk" patients (Stage IA Grade 3, IB-C and II), postoperative vaginal brachytherapy alone is probably sufficient to obtain a good therapeutic index. Results for patients with Stage III tumor are not satisfactory.

Adenocarcinoma↗

PubMed2001

[Automatic definition of prescription isodose for stereotaxic radiation of arteriovenous malformations].

PURPOSE: To evaluate dosimetric consequences generated by the automatic definition based on lesion coverage of prescription isodose. A clinical series of 124 arteriovenous malformations was analysed. Plan quality was quantified by the standard deviation of the differential dose volume histogram calculated in the lesion. MATERIAL AND METHODS: We define two quantitative protocols based on lesion coverage for the automatic definition of prescription isodose using a volumetric definition of coverage (90% of lesion volume), and an isodose-based definition proposed by RTOG (prescription isodose equals minimum isodose in the lesion divided by 0.9). RESULTS: We have evaluated the plans obtained for these two protocols, calculating several dose-volume indices. These indices are presented as a function of dose-volume histogram standard deviation in order to quantify the consequences of their variations for this representative series of plans. The margin our team tolerates is such that the sum of underdosed lesion and overdosed healthy tissues factors remains lower than one. Protocol based on volumetric coverage gives results situated within this margin. Protocol based on RTOG definition produces conformation indices that could be greater than 1. CONCLUSION: The absolute dose would be decided taking into account examined dose-volume indices and clinical data. A protocol for automatic definition of prescription isodose using volumetric lesion coverage seems to be more judiciously adapted to arteriovenous malformation conformal plans in stereotactic conditions because of variations observed in the overdosage of healthy tissues.

Algorithms↗

PubMed2001

[Radiotherapeutic basis of radiosurgery as applied to cerebral arteriovenous malformations: dose-volume effects].

BACKGROUND AND PURPOSE: To attempt to analyze the basic effects of radiosurgery as applied to cerebral arteriovenous malformations. METHODS: We reviewed and discussed the previous issues of the international literature concerning radiobiological principles of radiosurgery of arteriovenous malformations. RESULTS: The irradiated volume contained both a target volume consisting of abnormal vessels of the nidus often embedded within connective tissue stroma and the surrounding normal brain tissue. These were late-responding tissues after the radiation and sensitive tissues to high dose per fraction. There was not resistant hypoxic cell that could be killed efficiently with fractionated treatment. The therapeutic ratio between damage in the arteriovenous malformation nidus and late complications in the surrounding tissues was independent of fractionation. Furthermore, sterilization of all clonogenic cells in the target volume was not necessary to obtain complete obliteration of arteriovenous malformation. Consequently, there was nothing to be gained by a fractionated course relative to a stereotactic high single-dose irradiation for a small targeted volume (<=25 mm in diameter or<=4 200 mm(3)). The minimum target dose (Dmin) seemed to be the dosimetric independent predicting factor for complete obliteration. The Dmin-response relationship suggested a threshold dose of 5 Gy to 10 Gy and the better effects following Dmin from 20 Gy to 25 Gy. A Dmin above 25 Gy significantly increased the risk of serious late complications. The treated volume seemed to be the significant independent predicting dosimetric factor for developing persistent symptomatic sequelae. The optimum dose to deliver to obtain complete obliteration of an arteriovenous malformation was selected by balancing the expected obliteration rate for each dose with the corresponding risks from radiosurgery depending on size, location, shape and dose distribution. CONCLUSION: Although the basic pathological process is still uncertain there is a strong rationale for stereotactic radiotherapy delivered in a high single-dose for small arteriovenous malformations.

Blood Vessels↗

PubMed2001

[Importance of quantitative evaluation in the planning of the stereotactic irradiation of complex cAVMs].

BACKGROUND AND PURPOSE: The purpose was to present the successive steps of dosimetric planning and the different means used to allow the choice of the best solution among several planning projects considering the anatomical and clinical features of arteriovenous malformation. Method. Four successive steps were: A study of these factors for 5 different plannings of a clinical case using different isocenters is presented and the results are discussed. CONCLUSION: For complex arteriovenous malformations several hours are often necessary to permit physicians/radiotherapists to elaborate planning which is often a compromise among several solutions.

Cerebral Angiography↗

PubMed2001

[Radiosurgery of cerebral arteriovenous malformations: methodology of the dose prescription and its implications for dosimetric results. Retrospective study of 408 cases].

PURPOSE: To study dosimetric implications of our group dose prescription methodology on a series of 408 cerebral arteriovenous malformations. MATERIAL: and method. Between January 1990 and July 1998, 408 patients with cerebral arteriovenous malformations that had never been irradiated before, were treated radiosurgically in a single fraction at Tenon Hospital. 223 patients were treated with a single isocentre and 185 with multiple isocenters. Dosimetric characteristics have been studied as a function of the global quality index of planning, defined our group as the standard deviation of the differential dose volume histogram calculated in the lesion. RESULTS: One percent correlation obtained between some dosimetric data and the global quality index of planning allowed to modelize by linear equations the connection between this quality index and minimum isodose in the lesion, mean doses and isodoses in the underdosed part of the lesion and in the complete lesion. This was done for mono isocentric cases and multi isocentric cases. CONCLUSION: Before the choice of the therapeutic dose and prescription isodose, it is therefore possible from the global quality index of planning to foresee isodoses modelized by the defined equations. So, the radiotherapist can compensate using the prescription since conformity is not perfect and thus attenuate healthy tissues overdosage.

Cohort Studies↗

PubMed2001

[Technique of Linac radiosurgery for cerebral arteriovenous malformations].

BACKGROUND AND PURPOSE: Description of the irradiation technique used by our group since 1986 for radiosurgery of cerebral arteriovenous malformations using Xrays minibeams from a linear accelerator. Method. The technique was elaborated by O. Betti in the early 80. He used several coronal arcs to irradiate the center of the target with X rays circular minibeams. Their diameter (6 to 20 mm) is chosen according to the size of the nidus. The patient is seated in a specially built armchair. His head is immobilized with the Talairach frame afixed in the calvarium by 4 special screws: they allow to remove the frame after stereotactic angiography and/or CTscan and to replace it to perform the stereotactic irradiation. The frame and the head rotate around an horizontal axis passing by the linac isocenter ie the center of the target volume. The combination of both movements: rotation of the Linac and rotation of the stereotactic frame covers a spherical sector representing the surface of portals of entry of the minibeams. The frame can slide on a plate allowing access to the entire brain. Results. The special seat and the frame are movable on curved rails allowing to avoid or reduce irradiation of the body of the patient. CONCLUSION: We have been using this system of irradiation in the seated position since 1986 to treat more than 900 patients.

Dose Fractionation, Radiation↗

PubMed2001

[Technologic developments in radiotherapy and stereotactic radiosurgery].

We present a review of current technological progress enabling improvement in the quality of stereotactic irradiations: imaging fusion; individual adaptation of dosimetric planning to the shape of the target thanks to several collimation systems, spatial modulation of the beam with the use of multileaf microcollimators, beam intensity modulation, robotisation of the materials, owing to hardware and software developments.

Brain Neoplasms↗

PubMed2001

[Cerebral arteriovenous malformations treated by radiosurgery: a series of 705 cases].

BACKGROUND AND PURPOSE: After a review of the main radiosurgical published series, to evaluate our own series of 705 patients with cerebral arteriovenous malformations treated by radiosurgery alone or in combination with embolization or surgery. PATIENTS: and method. From January 1984 to December 1998, 705 patients were treated by a multidisciplinary team including neurosurgeons, neuroradiologists, radiophysicians and radiotherapists. Age of revelation of the cerebral arteriovenous malformations ranged between birth to 73 years (mean 27, median 25). Age at time of radiosurgery ranged between 7 and 75 years (mean 33, median 31). There were 410 males for 295 females (sex- ratio 1.4). Symptoms of revelation were hemorrhage for 59%, seizures for 23%, headaches for 14% and progressive deficits for 4%. Discovery of cerebral arteriovenous malformation was fortuitous in 4% of cases. Repartition following Spetzler's grading was 12% in grade I, 36% in grade II, 40% in grade III, 12% in grade IV and 0% in grade V. Maximal size ranged between 4 and 60 mm (mean 23, median 20). Volume ranged between 0.2 and 24.3 cc (mean 3.8, median 2.8). Majority of cerebral arteriovenous malformations were large size (42% with size higher than 25 mm) and large volume (54% higher than 10 cc. 54% of patients had treatment prior radiosurgery: 38% had embolization, 10% were operated, 4% were treated by radiosurgery (reirradiation) and 3% were operated and embolized. RESULTS: Overall complete obliteration rate was 55%. The obliteration rate was correlated with size (77% for cAVMs lower than 15 mm, 62% for cerebral arteriovenous malformations between 15 and 25 mm, and 44% for cerebral arteriovenous malformations higher than 25 mm), with volume (94% for cerebral arteriovenous malformations lower than 1 cc, 64% between 1 and 4 cc, 48% between 4 and 10 cc, and 62% for cerebral arteriovenous malformations higher than 10 cc), dose at reference isodose, minimal dose, morphological parameters (presence of dural components, arteriolovenous fistula, plexiform angioarchitecture, arterial steal, arterial recruitment, deep exclusive drainage, venous plicature, venous confluence, venous ectasia, venous reflux), sectional topography and good recovery of the target. Embolization was a confusion factor not associated with obliteration rate. After multivariate analysis, only Dmin and complete coverage of the cerebral arteriovenous malformations were correlated with obliteration rate. Delay of obliteration was significantly correlated after multivariate analysis with Dmin, complete coverage, arteriolovenulary angioarchitecture (positive correlation) and venous ectasia (negative correlation). CONCLUSION: Overall complete obliteration rate is unreliable data to assess efficacy of radiosurgical method in the tretment of cerebral arteriovenous malformations. The obliteration rate must be interpretated after stratification on several morphological and dosimetric parameters.

Adolescent↗

PubMed2001

[Radiosurgery of choroidal and cisternal cerebral arteriovenous malformations].

PURPOSE: Cerebral arteriovenous malformations surrounded by cerebrospinal fluid seemed to exhibit worse response to radiosurgery than others. We searched to verify if this is was true and to find causes. MATERIAL: and methods. From our series of 705 patients with cerebral arteriovenous malformations treated by radiosurgery, 3,8% (27/705) had choroidal or cisternal arteriovenous malformations. Revelation mode was hemorrhage in 86% of cases but sometimes headaches occurred before hemorrhage; thus overall hemorrhage rate was 96%. Mean age of revelation was 24. Mean size was 20 mm, mean volume was 4 cc. Spetzler & Martin's grades were 35% in grade II, 43% in grade III and 22% in grade IV. Location was ventricular in 63% of cases and cisternal in 37%. Mean dose at reference isodose was 24 Gy with a higher rate of monoisocenters. We looked for differences between this population of arteriovenous malformations and the rest of the series for patients, treatments prior radiosurgery, cerebral arteriovenous malformations's characteristics, dosimetric parameters and complications. Statistical analysis was done with a Pearson chi2 test and Spearman non parametric correlation test. RESULTS: Obiteration rate was 47.6% with a mean delay of 26 months. Differential characteristics of choroidal or cisternal arteriovenous malformations were: younger age of revelation, higher frequency of hemorrhage, of intra or paranidal aneurysms, of deep unique drainage, a higher Spetzler grade and a smaller rate of complete recovering. Mortality and clinical morbidity due to radiosurgery were 0%. Actuarial rate of hemorrhage after radiosurgery was 4,34% per year and per patient or per hemorrhage. This rate was higher than in the global series. Parenchymal changes seen on MRI were less frequent (26,6%) and less serious (no grade 4 radionecrosis-like parenchymal changes). CONCLUSION: Choroidal or cisternal arteriovenous malformations seem to respond less to radiosurgery than others. One potential explanation is the higher frequency of multiafferences of these arteriovenous malformations with anastomoses of anterior and posterior choroidal arteries. However, radiosurgery still stay a treatment of choice for these arteriovenous malformations with little adaptations of the irradiation strategy.

Adolescent↗

PubMed2001

[Radiosurgery for large cerebral arteriovenous malformations].

BACKGROUND AND PURPOSE: Treatment of large cerebral arteriovenous malformations is a challenge for embolization, surgery and radiosurgery too. The purposes of this study is to review results of RS for these large cerebral arteriovenous malformations and to study recent methods which can allow to improve results. PATIENTS: and method. From our series, 112 patients had cerebral arteriovenous malformations higher than 30 mm or 10 cc at time of the radiosurgery. Revelation mode was hemorrhage in 47%, seizures in 42%, headaches in 16%, and progressive neurological deficits in 7%. Discovery was fortuitous in 2.7% of cases. Before radiosurgery, 57% were embolized, 5% were operated, 4.5% were reirradiated and 1.8% were operated and embolized. Distribution according to Spetzler & Martin's grade was following: 0% in grade I, 12% in grade II, 41% in grade III and 46% in grade IV. No patient was in grade V. RESULTS: Global obliteration rate was 39% for large cerebral arteriovenous malformations. In multivariate analysis, only recovering (positive correlation), and previous embolization (negative correlation) were correlated with obliteration rate. CONCLUSION: Current procedures of radiosurgery allow obliteration in a limited number of large cerebral arteriovenous malformations treated. Other strategies as fractioned irradiation, multileaf microcollimators with single isocenter, radiosurgery before surgery or radiosurgery with protons should improve obliteration rate.

Adolescent↗

PubMed2001

[Radiosurgery of cerebral arteriovenous malformations in children].

BACKGROUND AND PURPOSE: Radiosurgery has been used in a few cases of cerebral arteriovenous malformations in children. From data of our series and from literature, we tried to determine the place of this therapeutic modality for treatment of pediatric cAVMs. PATIENTS AND METHOD: From the whole series of 705 patients treated by radiosurgery between January 84 and December 1998, 55 were under 15 years of age. Revelation mode was hemorrhage (70.9%), seizures (12.7%), headaches (10.9%) and neurological progressive deficits (1.8%). Size ranged from 5 to 50 mm (mean: 22 mm) and volume ranged from 1 to 16 cc (mean: 4 cc). Treatments prior radiosurgery were embolization alone (28%), surgery alone (16.7%), embolization plus surgery (5.5%). Distribution of cerebral arteriovenous malformations according to Spetzler & Martin's grading were 10% in grade I, 35% in grade II, 40% in grade III, 15% in grade IV and 0% in grade V. RESULTS: Overall obliteration rate was 59% with an exaustibility rate of 80%. Obliteration rate was dependent on size and volume (100% for<1 cc cerebral arteriovenous malformations sized, 73% from 1-4 cc, 40% from 4-10 cc and 100% (but n=1)>10 cc; p=0.019), sex (84.2% for boys and 40% for girls), of angioarchitecture and Dmin (p=0.01). After multivariate analysis, only Dmin was nearly correlated with the obliteration rate (b=0.462 7; SE=0.244 0; p=0.057). Actuarial risk of hemorrhage was 2.12% per year per patient. Patients with seizures were seizure-free without any drugs after radiosurgery in 80% of cases. Parenchymal changes were mainly hypersignals spT2 in MRI. CONCLUSION: Radiosurgery seems to be an efficient treatment with a low morbidity for cerebral arteriovenous malformations in children.

Adolescent↗

PubMed2001

[Retrospective analysis of failures in radiosurgery treatment of cerebral arteriovenous malformations].

The aim of this paper is to analyze retrospectively the reasons for the failure in cerebral arteriovenous malformations radiosurgery. Several factors are evoked and discussed mainly: inaccurate target, intentional partial irradiation, repermeabilization of a previously embolized cerebral arteriovenous malformation. The results suggest the necessity of a complete irradiation of the nidus. The strategy of partial volume irradiation should be avoided, even if it necessitates lowering of the doses in large cerebral arteriovenous malformations. Accuracy in the target determination is required and a complete stereoangiography is necessary.

Adolescent↗