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B Prevost

Publications and source records attributed to B Prevost.

At least 19 recordsLinked to original sources
PubMed2000

Microwave thermochemotherapy in the treatment of the bladder carcinoma--electromagnetic and dielectric studies--clinical protocol.

Microwave thermotherapy is currently used in clinical routines for benign prostatic hyperplasia treatments. The temperature increase is obtained using an endocavitary microwave applicator placed in the prostatic urethra. This urethral applicator after a technical modification can be placed inside the bladder in order to potentiate the effects of the treatment by chemotherapy of vesical carcinoma. This paper deals with electromagnetic studies of this new endocavitary applicator. First of all, the experimental determination of the dielectric permittivities for the propagation domain characterization is achieved in order to be used in the electromagnetic model. Compared to experimental results, these simulations obtained by the finite-difference time-domain formalism allow us to determine the electromagnetic performance of this applicator. Finally, the in vivo study realized on anesthetized dogs to determine the therapeutic protocol associating chemotherapy and thermotherapy in the treatment of the bladder cancer is presented.

Animals↗
PubMed1999

[Study of the synergy of microwave hyperthermia/intravesical chemotherapy in the prevention of recurrences of superficial tumors of the bladder].

OBJECTIVES: Preliminary clinical studies of the combination of hyperthermia and intravesical chemotherapy indicated very encouraging results in favour of multidisciplinary treatment of recurrent superficial bladder tumours. The authors studied the in vitro and early in vivo effects of this treatment. MATERIAL AND METHODS: An intravesical catheter equipped with a microwave antenna was used for hyperthermia in vivo in dogs. The temperature was controlled by two intravesical thermocouples and 4 transducers on the bladder wall. 0, 40 or 80 mg of mitomycin were instilled in 60 ml of physiological saline. Dogs were sacrificed after each one-hour session, and histological intravesical lesions were defined as grade 0, 1 or 2 corresponding to absence of lesions, or the presence of inflammatory lesions or urothelial lesions, respectively. In vitro, the first step consisted of creation of an immortalized tumour cell line from a grade II bladder papilloma. This HVT 196 cell line was incubated between 37 degrees C and 44 degrees C with increasing mitomycin concentrations of 0 to 10 micrograms per ml. The cytotoxicity was measured by the MTT quantitative colorimetric method. RESULTS: In vivo, in 8 dogs, histological analysis of the comparative cytotoxicity of the various treatments confirmed the synergistic effect of heat and mitomycin C. In dogs treated at 45 degrees C, marked urothelial lesions were observed, regardless of the mitomycin C concentration. The in vitro comparative toxicity study on our cell line showed a much more intense cytotoxic effect with combined treatment than with cytostatic treatment alone. Expressed as the percentage of cytotoxicity compared to a control cell pool for a concentration of 1 microgram per ml. the temperature rise of the medium between 37 degrees C and 44 degrees C was accompanied by a cytotoxic effect of 8.4% and 98.41% respectively. CONCLUSION: A possible clinical application is potentiation of the action of mitomycin C by hyperthermia in the prevention of recurrent superficial bladder tumours, achieving increased efficacy and/or a decreased number of instillations.

Administration, Intravesical↗
PubMed1998

Concomitant b.i.d. radiotherapy and chemotherapy with cisplatin and 5-fluorouracil in unresectable squamous-cell carcinoma of the pharynx: clinical and pharmacological data of a French multicenter phase II study.

PURPOSE: The aim of this phase II study conducted on unresectable squamous cell carcinoma (USCC) of the oro- and hypopharynx was to associate twice-a-day (b.i.d.) continuous nonaccelerated radiotherapy with concomitant cisplatin (CP)-5-fluorouracil (5-FU) chemotherapy, both given at full dose. Feasibility, efficacy, survival, and pharmacokinetic-pharmacodynamic relationships were analyzed. METHODS AND MATERIALS: Fifty-four consecutive patients with strictly USCC of oro- and/or hypopharynx received continuous b.i.d. radiotherapy (RT) (2 daily fractions of 1.2 Gy, 5 days a week, with a 6-h minimal interval between fractions). Total RT dose was 80.4 Gy on the oropharynx and 75.6 Gy on the hypopharynx. Three chemotherapy (CT) courses of CP-5-FU were given during RT at 21-day intervals (third not delivered after the end of RT). CP dose was 100 mg/m2 (day 1) and 5-FU was given as 5-day continuous infusion (day 2-day 6: 750 mg/m2/day cycle 1, 750 mg total dose/day cycle 2 and 3). Pharmacokinetics was performed for 5-FU (105 h follow-up) and CP (single sample at 16 h). Special attention was paid to supportive care. RESULTS: Good feasibility of RT was observed (85.2% of patients with total dose > 75 Gy). Five patients received 1 CT cycle, 34: 2 cycles, and 15: 3 cycles. The most frequent and severe acute toxicities were mucositis with grade 3-4 occurring in 28% at cycle 1 and 86% at cycle 2, as well as neutropenia (43% at cycle 2). Locoregional control at 6 months was observed in 66.7% of patients. No late toxicity above grade 2 RTOG was noticed. CP dose and 5-FU AUC(0-105h) were significantly linked to grade 3-4 neutropenia (cycle 2). Cumulative total platinum (Pt) concentration and Karnofsky index were the only independent predictors of locoregional control at 6 months. Finally, total RT dose and total Pt concentration were the only independent predictors of specific survival. CONCLUSION: This protocol showed good locoregional response with an acceptable toxicity profile. Pharmacokinetic survey is probably an effective approach to further reduce toxicity and improve efficacy. A multicentric randomized phase III study, now underway, should confirm these encouraging results.

Adult↗
PubMed1997

[Iris metastases. Apropos of 4 cases].

Metastatic tumors of the iris are rare. They most commonly arise from a primary breast or lung neoplasm and are associated with widespread carcinomatosis. They appear as white pink masses; anterior uveitis and hypertony can be seen. They are most often associated with short life expectancy. We report four cases and we show the interest of radiotherapy.

Adult↗
PubMed1997

Study of the effects of thermotherapy in benign prostatic hypertrophy.

UNLABELLED: Prostatic transurethral thermotherapy was evaluated clinically using the Prostcare microwave system of the Bruker Company, which uses a microwave radiometer to measure and control intraprostatic temperature. OBJECTIVES: The aim of our study was to evaluate the immediate histological lesions induced in the prostatic tissue depending on the temperatures delivered to the prostate; the histological changes when adenectomy is carried out after thermotherapy, and the endoscopic appearance of the prostatic fossa 48 h, and 1, 2, 3 and 6 months after thermotherapy. METHODS: Our study was divided into three stages: in the first stage, we conducted thermotherapy in 10 patients in whom suprapubic adenectomy was indicated. During thermotherapy, a multipoint fiber-optic receptor and two thermocouples were implanted into the prostage gland at a distance of 5-15 mm from the urethra. Adenectomy was carried out 10 min after thermotherapy; the second stage of our study concerned the changes seen over time. We heated adenomas using the same protocol and carried out adenectomy 24, 48, 72 h, and 1 week, 6 weeks and 3 months after thermotherapy, and lastly, we studied the endoscopic appearance after a single heating-session of 30 min by endoscopic controls at different times after thermotherapy (48 h, 1, 2, 3 and 6 months after thermotherapy). RESULTS: Macroscopic appearance: necrotic lesions measured 30 mm in length on average. Necrosis was roughly circumferential. Immediate histological aspect: in all cases, histological examination showed coagulation necrosis with periurethral thromboses. Histological changes: at 8 days, necrosis intensity was maximal and histological structures were difficult to identify. Endoscopic appearance: 3 months after thermotherapy, the typical endoscopic appearance was a large periurethral cavity. There was a sharp demarcation between untreated areas and cicatricial tissue. CONCLUSION: The efficacy of thermotherapy depends on the radiometric temperature, which should reach 47 degrees C (i.e. a temperature of 55-65 degrees C delivered to the prostate), and a rapid increase in temperature, i.e. in the power applied, which should reach the thermal radiometric level of 47 degrees C in 5 min. As soon as necrosis is obtained, the power is automatically reduced. Using this protocol, heating proves effective in 30 min.

Humans↗
PubMed1996

[Results of postoperative cervical node irradiation in carcinoma of the pharyngo-larynx. A study of the cooperative group of radiotherapists].

From 1981 to 1985, 428 patients presenting with an epidermoid carcinoma of the hypopharynx and/or larynx were treated with a curative intent by surgical resection and postoperative irradiation. Two-thirds of the tumours were T3 and 60% of patients presented with a clinical node involvement. The rates of local failure were 8%, 18% and 13%, respectively, for cancers of the larynx, of the piriform sinus and of the posterior wall; the rates of regional failure were 8%, 23% and 13%, respectively. There is no head and neck site with either a high or low risk of recurrence after resection, but the capsular rupture remains a factor of poor prognosis. The survival rate at 5 years of the whole series is 38%, for laryngeal localisation it reaches 62%. The risk of metastases is related to the node involvement and the interval between surgery and irradiation.

Actuarial Analysis↗
PubMed1995

[Postoperative radiotherapy in carcinoma of the pyriform sinus. Work of the "Groupe radiothérapie de la Féderation national des centres de lutte le cancer"].

Between January 1980 to December 1985, 248 patients with advanced squamous cell carcinoma of the pyriform sinus were retrospectively analysed. Criteria for inclusion in the study were the following: no previous treatment and treatment combining total pharyngolaryngectomy and postoperative radiotherapy. Mean follow up was 5 years with a minimum of 3 years. Seventy-one patients had a local regional recurrence (27.4%). Clinical staging at presentation and residual tumor at the primary site after surgery were factors significantly associated with higher local failure rates. The 5 year survival rate was 33% and the median survival time was 32 months (plateau was reached after the 6th year). The most frequent severe complication observed was pharyngeal stenosis occurring in 6% of the cases. This study confirms the poor prognosis of squamous cell carcinoma of the pyriform sinus, in spite of the combination of radical surgery and high dose postoperative radiotherapy.

Carcinoma, Squamous Cell↗
PubMed1994

Management of early oral cavity cancer. Experience of Centre Oscar Lambret.

From 1974 to 1983, 579 patients presenting with early oral cancer (excluding lip tumours) were treated at Centre Oscar Lambret. Of these, 429 were treated locally by brachytherapy with local control achieved in 82% of the cases (90% after salvage surgery). Treatment-related complications occurred in 19% of the cases, requiring surgical management in 13 patients. In contrast, only 51% of the 35 patients treated by external radiotherapy and brachytherapy were controlled, resulting in a poor 5-year survival (14%). Results for the 24 patients treated surgically were similar to those of brachytherapy alone. Finally, for T1 T2 N0 patients, the advantages of an elective neck dissection are not clear and could be clarified by a randomised trial. Indeed, this retrospective study failed to find a significant difference in the incidence of death due to an uncontrolled neck evolution whatever the neck management.

Adult↗
PubMed1993

Composite resection with mandibulectomy in the treatment of posterolateral oral cavity and lateral oropharynx squamous cell carcinoma.

From 1972 to 1987, 403 patients underwent a composite resection consisting of segmental mandibulectomy and neck dissection for the treatment of bucco-pharynx squamous cell carcinoma (303 patients had postoperative radiotherapy [XRT], 29 patients had preoperative XRT, and 100 patients had tissue salvage performed after XRT). Of the 303 patients who received preoperative XRT, 32 were clinically staged T2, 149 were staged T3, and 122 were staged T4; 194 of the 303 patients were staged N0. In the 100 patients who experienced relapse and who required "salvage surgery," the restaging found 20 patients staged T2, 39 staged T3, and 41 staged T4; 73 of the 100 patients were staged N0. The patients' mean postoperative stay was 15 days for those who had prior surgery and 21 days for those who had salvage surgery. With a minimum follow-up of 5 years, locoregional recurrences and postoperative death occurred in 86 of 274 patients (31%) in whom surgery and postoperative XRT were performed; in 17 of 29 patients (59%) who had preoperative XRT performed; and in 61 of 100 patients (61%) who had salvage surgery performed. In addition, in terms of functional results, only 61% of patients (206) were able to maintain normal speech function, and only 23% (91) were able to maintain normal oral feeding. Of the 403 patients, the 5-year survival rates were 33% for the overall population, 42% for patients with postoperative XRT, 16% for patients in whom operation was performed after preoperative XRT, and 17% for patients who underwent salvage surgery.

Adult↗
PubMed1992

Results of postoperative radiation therapy in medullary carcinoma of the thyroid: a retrospective study by the French Federation of Cancer Institutes--the Radiotherapy Cooperative Group.

Between 1971 and 1989, 59 patients received external radiation therapy with a curative intent. There were 25 females and 34 males, ranging in age from 19 to 87. No patients had distant metastasis at the onset of treatment. The majority of patients had a total thyroidectomy (55/59), generally combined with neck dissection. Residual tumour was left in 11 cases, and 44 patients had positive cervical nodes. Using megavoltage radiotherapy, the whole neck and the upper mediastinum area were most often irradiated through a large anterior Y-shaped field without laryngeal shielding. The mean dose to the tumoral bed was 54 Gy. Dysphagia was observed in 32 patients (11, 17 and 5 scores were grade 1, 2 and 3, respectively). Dyspnea occurred in five cases and in two of these cases, it was considered to be severe. Local recurrences were noted in 18 (30%) patients, most of them occurring within the fields of irradiation. Parameters such as age, sex, total dose, irradiated volumes or cervical node enlargement did not modify the local control rate. The same conclusions can be drawn for distant failures. Thirty five patients are still alive and among them, 24 have no evidence of disease. The average length of survival is 70.5 months and is shortened by the occurrence of distant failures except in patients with bone metastases.

Adult↗
PubMed1989

[Cancer of the upper aerodigestive tract. Global study of 2418 cases].

The authors present the general results of a retrospective study on 2418 patients treated between 1976 and 1980. Primaries were located on buccopharynx in 51% of cases, pharyngolarynx in 45% and nasopharynx or nasal and paranasal cavities in 4%. Two out of 3 tumours were classified T3 T4 (UICC 1979) and 1 out of 2 patients presented with palpable cervical lymph nodes. Taking into account persistent diseases and recurrences, failure at primary sites occurred in 40% of patients, in the neck in 20%, distant metastases in 10%. Synchronous and/or metachronous cancers were observed in 1 out of 3 patients. Actuarial survival rates were 2/3 at 1 year, 1/3 at 3 years, 1/4 at 5 years and 1/7 at 8 years. Endolaryngeal tumours had the best prognosis while hypopharyngeal tumours had the worst prognosis.

Adult↗
PubMedDate not supplied

Interstitial brachytherapy and early tongue squamous cell carcinoma management.

The results of treatment of 341 previously untreated patients with early squamous cell carcinoma (SCC) of the anterior two thirds of the tongue using iridium 192 implants (January 1974-December 1983) are presented. Furthermore, 265 patients underwent neck dissection, followed, in 102 cases, by radiotherapy. Incidence of local treatment complications was 19% (66 patients; however, only 3% (11 patients) needed more than a single medical treatment. Two months after completion of overall treatment, 326 patients (96%) were free of disease. Local failures occurred in 18% of cases; however, after successful salvage surgery this rate was reduced to 11%. Neck failures occurred in 18% of cases, but after successful salvage were reduced to 12%. Distant metastases were rare (1.5%), whereas metachronous cancers were frequent (102 patients). Survival rates were 61% (56% to 66%) at 3 years, 46% (41% to 51%) at 5 years, and 26% (23% to 34%) at 10 years. Deaths due to tongue cancer evolution (20%) equalled those due to metachronous cancers (18.5%) and intercurrent diseases (21%).

Adult↗
PubMedDate not supplied

Epilarynx: pharynx or larynx?

BACKGROUND: As a general rule, epilarynx is studied as a part of supraglottis. On the contrary, in France, due to its particular natural history, it is often studied separately. METHODS: To assess the value of this French classification, we compared from an epidemiologic point of view, in one study, 86 cases of epilarynx squamous cell carcinoma (SCC) with 431 oropharynx, 339 hypopharynx, and 89 vestibule SCC. In another study, we compared, from a clinical point of view, 232 epilarynx SCC with 1351 oropharynx, 652 hypopharynx, and 372 vestibule SCC. RESULTS: Epilarynx patients appeared to be much heavier drinkers than larynx patients and similar to pharynx patients but tobacco consumption did not differ. The patterns of nodal involvement were similar for pharynx and epilarynx SCC. For stages I and II, patterns of failures were similar, but for stages III and IV, there were fewer locoregional failures in vestibule patients; distant metastases were equally frequent for these tumors. From the standpoint of multiple primaries, epilarynx SCC appeared to be more akin to pharynx than to larynx SCC with a much lower incidence of lung cancers. Finally, the outcome after treatment was different for vestibule, epilarynx, and pharynx SCC, with a 5-year survival of 43%, 27%, and 13%, respectively. CONCLUSIONS: These data support the identification of epilarynx as a real entity that should be taken into account for stratification in clinical trials.

Actuarial Analysis↗
PubMedDate not supplied

Pronostic factors of synchronous brain metastases from lung cancer.

BACKGROUND: The prognosis of brain metastases (BM) from lung cancer is poor. The management of lung cancer with BM is not clear. This retrospective study attempts to determine their prognostic factors, and to better define the role of different treatments. METHODS: We reviewed the clinical characteristics of 271 consecutive patients with synchronous brain metastases (SBM) from lung cancer (small-cell lung cancers and non-small-cell lung cancers), collected between January 1985 and May 1993. Data were available for all patients as well as follow-up information on all patients through to death. Patients had all undergone heterogeneous treatments. Each physician had chosen the appropriate treatment after collegiate discussion. Survival curves were compared using the log-rank test in univariate analysis, and Cox's Regression model in multivariate analysis. Statistical significance was defined as P<0.05. RESULTS: 249 patients were assessable. Treatments included: neurosurgical resection in 56 cases, brain irradiation in 87 cases, and chemotherapy in 126 cases. Median overall survival time from the date of histological diagnosis of SBM was 103 days (range, 1-1699). In multivariate analysis, prognostic factors for longer overall survival times were: absence of adrenal metastases (P=0.007), neurosurgical resection (P=0.028), chemotherapy (P=0.032) and brain irradiation (P=0.008). Moreover, risk factors of intracranial hypertension as cause of death were number of SBM and absence of neurosurgical resection. CONCLUSIONS: These results and others suggest that patients with SBM from lung cancer be considered for carcinologic treatment, and not only for best supportive care. However, further studies are necessary to evaluate quality of life with or without carcinologic treatment.

Adult↗
PubMedDate not supplied

New 434 MHz interstitial hyperthermia system monitored by microwave radiometry: theoretical and experimental results.

A new complete microwave interstitial hyperthermia system monitored automatically by microwave radiometry and working at 434 MHz is described in this paper. This system, which includes a new radiometer with two internal temperature references, is detailed. All its characteristics for microwave heating and radiometry are presented. The new possibilities are shown through numerous experiments on acrylamide phantom and excised tissues, which have been carried out for different antennae implantation corresponding to the clinical situation. The clinic protocol, associate to the brachytherapy, imposes the use of semi-loop catheters. Coaxial antennae, inserted in these catheters, are not, therefore, positioned in a rectilinear manner but undergo a curve. So, models based on the FDTD formalism are developed to determine the theoretical power deposition. Owing to these models, the effects of this physical motive on radiation diagrams can be taken into account. The results of the power deposition are presented for two antennae. Thermal patterns can then be determined by the solution of the bioheat-transfer equation in the steady state. Also, the comparison of the results given by the new interstitial hyperthermia system with those obtained with the previous 915 MHz one shows an improvement of the thermal performances.

Electromagnetic Fields↗