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P Maingon

Publications and source records attributed to P Maingon.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Patient positioning and its verification: justification, state of the art of the classical practices].

Patient immobilization is considered an important part of the quality control program in radiation therapy. The need for patient immobilization according to the symptoms, ensuring both reproducibility and comfort, is described in the recommendations for level 1 published by the SFPM (Société française de physique médicale) and the SFRO (Société française de radiothérapie oncologique). A customized device, associated with regular controls, is required for level 2. Customized procedures are mandatory in clinical practice for head and neck and brain treatments. Internal margins and movements of patients must be analyzed and controlled as deviations of CTV placement relative to the isocenter of linacs. They could be reduced with efficient positioning devices and accurate customized immobilization systems. Different devices could be used according to tumor locations. Except for subclavicular tumors, their efficacy remains controversial.

Abdominal Neoplasms↗
PubMed2000

[Assessment of the use of electronic portal imaging].

Improvement in the accuracy of the positioning of the patient during external irradiation is one of the most important issues of the last decades, due to the detrimental impact of the misplacements on treatment outcome. Since 1990, the evolution of the technologic environment has led to a full integration of the portal imaging devices into linac technology. It offers a real on-line verification tool for "high-dose, high-accuracy" treatments. This overview based upon data from the literature describes the different types of imaging devices, the strategies of use and the results obtained. It also considers the use of imaging devices as an in vivo dosimeter.

Humans↗
PubMed1999

Effects of combined irradiation and doxorubicin treatment on cardiac function and antioxidant defenses in the rat.

Combined radiotherapy and chemotherapy have represented a major advance in the therapeutic management of cancer therapy. However, the combination of doxorubicin (DXR) and cardiac irradiation (IRR) could precipitate the unexpected expression of congestive heart failure. Oxidative lesions induced by IRR and DXR could represent one of the pathogenic factors of myocardial dysfunction. Our investigations were performed to evaluate in the rat: 1) cardiac functional changes, 2) cardiac and plasma peroxidative damage and antioxidant defenses variations, that occur 24 h (acute effects) and 30 d (middle term effects) following DXR treatment 1 mg/kg(-1)/day(-1) IP for 10 d and a 1 x 20 Gy cardiac gamma-irradiation. Our results showed that DXR affected heart reactivity as early as the end of its administration, although irradiation exerted no detectable effect. Antioxidant defenses disturbances in hearts of DXR treated rats were characterized by vitamins C and E decreases, catalase activity induction and an increase in lipid peroxidation. Moreover, plasma vitamin C consumption and the lower level of plasma lipid peroxidation attested to the efficient solicitation of antioxidant defenses that probably contributed to the preservation of cardiac function at 24 h. After 30 d, cardiac dysfunction became symptomatic at rest, resulting from DXR cardiac toxicity. In spite of the persistent activation of cardiac catalase activity, antioxidant deficiency and increased plasma and cardiac lipid peroxidation highlighted defenses overtaken. Thus, different physiopathological mechanisms are involved in heart disturbance at acute and middle terms, IRR and DXR acting on distinct targets without disclosing synergistic effects. After 30 d, cardiac and plasma biochemical abnormalities were emphasized by the combined DXR+IRR therapy, pointing out the severity of the damage. Oxidative damage to the heart induced both by irradiation and DXR, may be one of the pathogenic factors of myocardial dysfunction. There is the possibility that the deleterious effects might be limited by the use of pharmacologic antioxidant agents.

Animals↗
PubMed1999

Survival rates of malignant gliomas in Burgundy from 1990 to 1995.

The aim of this study was to provide current data on case-fatality rates of malignant gliomas in the area of Burgundy (1,300,000 inhabitants). The ascertainment was specific according to imaging and histologic criteria, and was exhaustive because of the existence of a single University Hospital allowing both imaging and histologic diagnosis from stereotaxic cerebral biopsy. During six full years we collected 161 cases of malignant gliomas grades II to IV, 93 men (57.76%) and 68 women (42.23%). The mean age was 61 years. In all the age groups, there were a male predominance. Headache, epilepsy and motor deficit were the most frequent symptoms at onset. In most cases, the gliomas were localized within the frontal area. The post-surgical Karnofsky score was up to 70 in 40% of the cases. There were 89 glioblastomas with grade IV, 37 anaplastic astrocytomas, 13 gliomatous tumors with grade II and IV and six anaplastic oligodendrogliomas. This grading explains the very low survival rates, with a negative effect induced by age. Among the most relevant contributions of this study to the clinical features of malignant gliomas is an analysis of case-fatality rates, evaluation of health care services and therapeutic trials.

Adolescent↗
PubMed1998

Preoperative radiotherapy and surgery for endometrial carcinoma: prognostic significance of the sterilization of the specimen.

INTRODUCTION: We report a retrospective study on the analysis of the operative specimen after preoperative radiotherapy for FIGO (1971) stage I or II endometrial carcinoma. METHODS AND MATERIALS: From 1976 to 1996, 221 patients were treated with external radiotherapy (XRT) and/or low-dose-rate brachytherapy (BT) followed by surgery (S). Patients with cervical involvement (89 patients) or with high-grade tumors (49 patients) received XRT and BT. Patients stage FIGO Ia (89 patients) or with low-grade tumors (57 patients) received BT alone. Surgery was performed 5 to 6 weeks after irradiation. RESULTS: The mean follow-up is 78 months (12-216). The 5-year survival was 90% for FIGO Ia, 80% for FIGO Ib, and 84% for FIGO II (p = 0.51). According to the differentiation, 5-year survival was 87% for grade 1, 84% for grade 2, 84% for grade 3 (p = 0.10). Grade 3 complications were registered in 2% (no grade 4). The tumors were sterilized in 37 patients (17%), sterilized but with dystrophic glands in 34 patients (16%), only modified and altered in 21 patients (9.5%), with viable cells in 56 patients (26%). After preoperative radiotherapy, 37/148 specimens were sterilized (25%), 14/74 after brachytherapy and surgery (19%), 23/74 after external radiotherapy-brachytherapy and surgery (31%). According to the response of the specimen, 5-year survival was 87% when the tumor was sterilized, 96% when altered glands were present, 85% when modified, and 76% if residual tumor with viable cells was identified (p = 0.043). CONCLUSION: Preoperative radiotherapy followed by surgery is a safe and effective treatment of FIGO stage I or II endometrial carcinomas. BT with two uterine tubes seems to be of interest in the contribution of the treatment of the uterus to sterilize the specimen. The analysis of this new prognostic factor remains important to select a population with worst prognosis.

Adult↗
PubMed1998

Role of radiation therapy in the treatment of primary tracheal carcinoma.

PURPOSE: The objective of this work is to investigate the role of radiation therapy in the treatment of primary tracheal carcinoma. METHODS AND MATERIALS: From 1963 to 1993, 106 patients presenting with a tracheal carcinoma received a radiation course as part of their treatment in three institutions. Eighty-four patients were treated with megavoltage radiation only, receiving doses ranging from 30 to 70 Gy, with a median dose of 56 Gy. Five patients received high-dose-rate (HDR) brachytherapy, five patients underwent a surgical procedure, and eight received chemotherapy. RESULTS: With a mean follow-up of 141 months, the overall 1-, 2-, and 5-year survival rates are 46%, 21%, and 8%, respectively. Prognostic factors included tumor size (less than 3 cm), performance status, and total radiation dose: the 5-year survival rate dropped from 12% for patients receiving doses greater than 56 Gy to 5% for lower doses. Performance status and radiation doses are the only independent significant factors in multivariate analysis; these results must however be analyzed with precaution in this retrospective study. CONCLUSIONS: Radiation is a good alternative to surgery for primary tracheal cancer. A review of the literature and our current results allow us to recommend a radiation dose greater than 60 Gy for primary irradiation. Collaborative studies are warranted to (1) determine the optimal radiation dose for definitive irradiation, (2) define the potential role of radiation after complete and partial surgery, (3) determine the role and optimal treatment scheme for HDR brachytherapy, (4) describe and record the late effects, (5) establish the potential benefit of chemoradiation.

Adult↗
PubMed1998

Conservative management of rectal adenocarcinoma by radiotherapy.

PURPOSE: The aim of this study was to analyze the experience of Centre GF Leclerc for conservative and curative treatment by radiotherapy of low rectal cancer. PATIENTS AND METHODS: A total of 151 patients received radiotherapy alone for rectal adenocarcinoma with curative intent. They were clinically staged according to size (T1 < 3 cm, and T2 > 3 cm) and depth of infiltration (A=superficial, and B=impaired mobility and T3 fixed). Over the past 6 years, rectal ultrasound (US) has been used systematically, compared with computed tomographic scan and magnetic resonance imaging when needed. Intracavitary contact X ray was given to 129 patients (69%), and brachytherapy in 45 of 151. External radiotherapy was used in 34 cases (22.5%). RESULTS: Complete response was obtained in 93%. Local failures were observed in 50 cases (28%); two occurred in pelvic nodes after intracavitary X rays. Size (tumors > 3 cm) and alteration of mobility significantly influenced the rate of local failure (p=0.009 and 0.007). The addition of external radiotherapy in patients with poor prognostic factors improved the local control rate. A total of 39 patients with recurrence were amenable to salvage surgery. After salvage treatment, the local control rate was 82% with unlimited follow-up. The 5-year actuarial survival rate was 57%, with a specific survival of 66%. There was no difference in local control or survival according to differentiation of the tumors and distance between anal margin and the inferior level of the lesion. Severe late effect (grade 3) was 3.8%. The sphincter preservation was obtained in 104 of 124 cases (84%). The sphincter function was judged to normal in 102 of 104 patients (98%). CONCLUSION: Intracavitary contact X ray is the treatment of choice for clinical Stage T1A rectal tumors. External radiotherapy significantly improved the results of treatment of tumors > 3 cm. Clinical staging and transrectal ultrasound allows a safe selection of indications. Radiotherapy alone may be proposed for selected cases as an alternative to mutilating surgery for small rectal adenocarcinoma.

Adenocarcinoma↗
PubMed1998

[Adjuvant chemoradiotherapy of cancers of the rectum].

Increasing local control remains a major endpoint in the adjuvant setting of rectal cancer. Postoperative concurrent 5FU-based chemotherapy and irradiation demonstrated its value in Duke's B and C patients. Toxicity decreased from the first studies to the current one's in relation with better radiotherapy technique, reduction of chemotherapy duration and quality assurance programs. Because preoperative irradiation alone has demonstrated its value on local control and overall survival, preoperative combined chemoradiotherapy should be investigated. Phase III trials are ongoing comparing preoperative radiochemotherapy to either preoperative irradiation alone or to postoperative radiochemotherapy. At this moment, if the patient has been operated, radiochemotherapy and additional chemotherapy should be offered in the case of Duke's B-C tumor. On the other hand, it should be preferably offered preoperative radiotherapy in case of T3 resectable T4 and hopefully in the context of a controlled clinical trial investigating preoperative concurrent radiochemotherapy.

Antineoplastic Agents↗
PubMed1998

[Chemoradiotherapy in cancers of the uterine cervix].

Treatment of uterine cervix carcinomas is based on radiotherapy and surgery. Prognosis of advanced carcinoma leads to the proposal of many combinations. Only concurrent radio-chemotherapy demonstrated some interests. Combination of radiotherapy and radiosensitisers failed to demonstrate any advantage and in some instances was associated with an adverse effect. Hydroxyurea and mitomycin C alone or associated were extensively tested without benefit. From modern combinations and recent studies, we could conclude that only cisplatin (and probably its derivates) can be included in future trials.

Antineoplastic Agents↗
PubMed1996

Preoperative radiotherapy in stage I/II endometrial adenocarcinoma.

From 1972 to 1993, 170 patients received preoperative radiotherapy followed, 5-6 weeks later, by total extrafascial hysterectomy with bilateral salpingo-oophorectomy without lymphadenectomy. Eighty-three patients with good prognostic factors (low grade tumour and no cervical involvement) received low dose rate utero vaginal brachytherapy alone before surgery (Group 1). Eighty-seven patients with poor prognostic factors (high grade tumors and/or cervical involvement) received external radiotherapy to 40 Gy and low dose rate brachytherapy before surgery (Group 2). A single vaginal failure was observed (0.6%). The overall pelvic failure rate was 2.3% (four patients) including two cases with pelvic recurrence and metastases. Three of the four pelvic failures occurred in Group 1. Using the 1971 FIGO clinical staging, 5-year disease-free survival was 82% in Stage Ia, 79% in Stage Ib, and 81% in Stage II (P = 0.36). Five-year disease-free survival was 86% in Grade 1, 76% in Grade 2, and 83% in Grade 3 (P = 0.20). Five-year overall survival was 83% in Stage Ia, 79% in Stage Ib, and 83% in Stage II (P = 0.78). Five-year overall survival was 88% in Grade 1, 77% in Grade 2,83% in Grade 3 (P = 0.27). Complications were recorded with the French-Italian syllabus. Grade 2 complications occurred in 12 cases (7%), Grade 3 in five cases (3%). The lack of correlation between classical risk factors (stage, grade) and disease outcome suggests that preoperative radiotherapy strategies should be preferred when such factors can be identified before surgery.

Adenocarcinoma↗
PubMed1995

Effect of in vivo heart irradiation on the development of antioxidant defenses and cardiac functions in the rat.

During radiotherapy of thoracic tumors, the heart is often included in the primary treatment volume, and chronic impairment of myocardial function occurs. The cellular biomolecules are altered directly by radiation or damaged indirectly by free radical production. The purpose of this investigation was to evaluate the biochemical and functional responses of the rat heart to a single high dose of radiation. The effect of 20 Gy local X irradiation was determined in the heart of Wistar rats under general anesthesia. Mechanical performances were measured in vitro using an isolated perfused working heart model, and cardiac antioxidant defenses were also evaluated. Hearts were studied at 1 and 4 months after irradiation. This single dose of radiation induced a marked drop in the mechanical activity of the rat heart: aortic output was significantly reduced (18% less than control values) at 1 month postirradiation and remained depressed for the rest of the experimental period (21% less than control 4 months after treatment). This suggests the development of myocardial failure after irradiation. The decline of functional parameters was associated with changes in antioxidant defenses. The decrease in cardiac levels of vitamin E (-30%) was associated with an increase in the levels of Mn-SOD and glutathione peroxidase (+45.5% and +32%, respectively, at 4 months postirradiation). However, cardiac vitamin C and catalase levels remained constant. Since these antioxidant defenses were activated relatively long after irradiation, it is suggested that this was probably due to the production of free radical species associated with the development of inflammation.

Aging↗
PubMed1995

[Intraoperative radiotherapy. Preliminary results].

We report a series of 40 patients treated by intraoperative radiotherapy between 1988 and 1992 (18 primary tumors, 13 local recurrences and 9 nodal extensions). The doses delivered were 15 Gy to 25 Gy, completed by external radiotherapy (15 to 45 Gy) in 13 cases. The local tumor control rate was 61% for initial therapy in primary tumors (70% for adenocarcinoma of the stomach) and 80.9% after complete en bloc surgery. The local control rate after palliative surgery for local recurrences is 38% and 33% for nodal extension. Two patients died (5%) during the postoperative period. We observed 2 hemorrhages and 3 cases of stone-free cholecystitis. The value of this approach must be confirmed in rigorous indications in comparison with surgery alone in controlled and randomised clinical trials.

Adult↗
PubMed1994

Maximum and mean bladder dose defined from ultrasonography. Comparison with the ICRU reference in gynaecological brachytherapy.

The reference bladder dose for gynaecological intracavitary brachytherapy (BT), as defined by the ICRU 38 Report, is often criticised as it is seldom representative of the highest bladder dose nor it gives an idea of the area exposed to a significant dose. Since November 1990, ultrasound measurements are routinely made in order to determine the actual dose delivered to the bladder of each patient. The technique was as follows. (1) the bladder is filled up with 150-200 cm3 of sterile isotonic saline. (2) The intrauterine position of the tube is checked. (3) The bladder anatomy is controlled. (4) Points of measurements are identified: ICRU bladder reference, minimum distance between bladder mucosa, uterine tube and other similar measurements taken every 15 mm along the radio-active line. Maximum and mean doses are calculated at the sagittal plane. Measurements are performed by moving the transducer along the skin of the patient and included in the calculation of dose distribution. Doses delivered to each relevant point are compared. This enables determination to be made of the differences between the ICRU and the doses actually observed at the bladder wall with aid of ultrasonography. BT applications were checked in 58 patients (69 measurements). The method was feasible in all cases. The comparison between ICRU dose from orthogonal films and the ICRU dose from ultrasonography resulted in a 90% accuracy. The maximum and mean doses for utero-vaginal BT are higher than the ICRU dose in 75% of cases (range, 2-8). Measurements are now abandoned for vaginal applications as the ICRU dose only could be measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Brachytherapy↗
PubMed1994

Radiotherapy for head and neck cancers including chemoradiotherapy.

After two decades of clinical investigations on hyperfractionation, a 10% local control gain at 5 years was finally demonstrated by a large, randomized trial in oropharyngeal carcinoma, which confirms promising data from numerous uncontrolled studies. Moreover, this progress was achieved without additional late morbidity, in agreement with radiobiology predictions of the linear quadratic model. Data from in vivo measures of the survival fraction after 2 Gy and potential doubling time show a trend for a poorer prognosis in rapidly proliferating tumors, however, unequivocal evidence does not yet exist. Retrospective studies document the detrimental effect of prolonged overall treatment time and support investigations on accelerated radiotherapy as a priority. Reports on the combination of chemotherapy and radiotherapy (mostly concomitantly) still leave the reader with a feeling of frustration. All reports, except one, have a poor methodology without a control arm to use the best-known regimens of radiotherapy and surgery. Nasopharyngeal tumors should not be mixed up with other head and neck sites because impressive responses can follow adequate combination strategies of chemoradiotherapy. Xerostomia is no longer an unavoidable and hopeless side-effect of radiotherapy; individualized treatment planning and stimulation of remaining salivary glands by pilocarpine can improve the comfort in about 50% of irradiated patients.

Combined Modality Therapy↗