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Jean-Jacques Mazeron

Publications and source records attributed to Jean-Jacques Mazeron.

At least 19 recordsLinked to original sources
PubMed2006

Conformity index: a review.

We present a critical analysis of the conformity indices described in the literature and an evaluation of their field of application. Three-dimensional conformal radiotherapy, with or without intensity modulation, is based on medical imaging techniques, three-dimensional dosimetry software, compression accessories, and verification procedures. It consists of delineating target volumes and critical healthy tissues to select the best combination of beams. This approach allows better adaptation of the isodose to the tumor volume, while limiting irradiation of healthy tissues. Tools must be developed to evaluate the quality of proposed treatment plans. Dosimetry software provides the dose distribution in each CT section and dose-volume histograms without really indicating the degree of conformity. The conformity index is a complementary tool that attributes a score to a treatment plan or that can compare several treatment plans for the same patient. The future of conformal index in everyday practice therefore remains unclear.

Algorithms↗
PubMed2005

Successful combination of local CpG-ODN and radiotherapy in malignant glioma.

Oligodeoxynucleotides containing CpG motifs (CpG-ODN) display broad immunostimulating activity and are currently under clinical trial in various malignancies, including recurrent glioblastomas. Combining CpG-ODN with another therapy that could induce antigen release might enhance tumor-specific immune response. We investigated whether radiotherapy (RT) could be associated advantageously to intratumoral injections of CpG-ODN. Fisher rats bearing 9L glioma were treated with various combinations of RT and CpG-28, an oligonucleotide with good immunostimulating activity. RT and CpG-28 induced complete tumor remission in one-third of the animals. When both treatments were combined, complete tumor remission was achieved in two-thirds of the animals (p < 0.001 when compared to non-treated rats, p < 0.03 when compared to CpG-28 alone). Such efficacy was not observed in nude mice, underlying the role of T cells in antitumor effects. The combination of both treatments appeared optimal when the delay between RT and CpG-28 administration was <3 days (from 100% survival for a 3 days delay, to 57% survival for a 21 days delay, p < 0.05). Tumor infiltration by immune cells and expression within tumors of the CpG receptor, TLR9, were not modified by irradiation. These results support an attractive strategy of sequential radiotherapy and immunotherapy by CpG-ODN and have potential implications for future clinical trials with CpG-ODN.

Animals↗
PubMed2005

Functional outcome of patients with benign meningioma treated by 3D conformal irradiation with a combination of photons and protons.

PURPOSE: To evaluate efficacy and tolerance of external fractionated combination of photon and proton radiation therapy (RT) for intracranial benign meningiomas. METHODS AND MATERIALS: Between 1994 and 2002, 51 patients with intracranial meningiomas of the base of the skull were treated with a combination of photon and proton RT. Median total dose was 60.6 cobalt Gy equivalent (54-64). One hundred eight eye-related symptoms were collected; 80 other symptoms were noted and followed up. RESULTS: Mean follow-up was 25.4 months. Acute tolerance was excellent. Out of the 108 eye-related symptoms, 106 (96%) were evaluated. Improvements were reported for 73 (68.8%) of them. Out of the 88 other miscellaneous symptoms, 81 (92%) were evaluated. Improvements were reported in 54 cases (67%). Median time to improvement ranged from 1 to 24 months after completion of the radiotherapy, depending on the symptom. We did not observe any worsening of primary clinical signs. Radiologically, 1 patient relapsed 4 months after the end of irradiation. Pathology revealed a malignant (Grade 3) transformation of the initial Grade 1 meningioma. Four-year local control and overall survival rates were, respectively, 98% and 100%. Stabilization of the tumor was observed in 38 cases (72%), volume reduction in 10 cases (20%), and intratumor necrosis in 3 cases. Two patients complained of Grade 3 side effects: 1 unilateral hearing loss requiring aid and 1 case of complete pituitary deficiency. CONCLUSION: These results stressed the clinical efficacy of fractionated-associated photon-proton RT in the treatment of meningiomas, especially on cranial nerve palsies, without severe toxicity in almost all patients.

Adolescent↗
PubMed2005

Linac stereotactic radiosurgery: an effective and safe treatment for elderly patients with brain metastases.

PURPOSE: To evaluate the outcomes of radiosurgery for brain metastases in patients 65 years or older. PATIENTS AND METHODS: Between January 1994 and January 2003, 117 patients (47 women, 70 men), median age 71 years (range, 65-86 years), received radiosurgery for 227 metastases. Sixty-one patients (55%) presented symptoms in relation to the brain metastases. Thirty-eight patients (32%) received whole-brain radiotherapy. Median metastasis diameter and volume were 21 mm (range, 0.5-75 mm) and 1.7 cc (range, 0.02-71 cc), respectively. RESULTS: Median follow-up was 7 months (range, 1-45 months), 9.5 months for alive patients (range, 1-45 months). Median minimum and maximum doses were 14.5 Gy (6.5 Gy, 19.5 Gy), and 20.4 Gy (13.2 Gy, 41.9 Gy), respectively. Median survival was 8 months from the date of radiosurgery. Overall survival rates at 6 and 24 months were 58% +/- 5% and 13% +/- 4%, respectively. According to multivariate analysis, a low Karnofsky performance status was an independent unfavorable prognostic factor for overall survival (p = 0.003; odds ratio [OR] = 0.28; 95% confidence interval [CI], 0.14-0.56). Median brain disease-free survival was 10 months. Brain disease-free survival rates at 6 and 24 months were 67% +/- 6% and 40% +/- 7%, respectively. According to multivariate analysis, a radiosensitive lesion was an independent favorable factor (p = 0.038; OR = 0.42; 95% CI, 0.18-0.95); more than two metastases and a low Karnofsky performance status were independent unfavorable factors for brain disease-free survival (p = 0.046; OR = 2.15; 95% CI, 1.01-4.58 and p = 0.003; OR = 30.4; 95% CI, 3.1-296, respectively). Local control rates were 98% +/- 2% and 91% +/- 8.5% at 6 and 24 months. Out of the 61 patients presenting symptoms before radiosurgery, complete symptomatic response was achieved in 12 patients (20%), partial improvement in 25 (41%), stabilization in 7 (11%), and worsening in 4 (6%) related to a progression of the irradiated metastasis. Seven cases of radionecrosis were described and were related to the margin dose (p = 0.03). CONCLUSION: Radiosurgery for elderly patients was effective and safe. Age alone should not be a criterion for denying radiosurgery to any patient with brain metastases.

Aged↗
PubMed2005

Chordomas of the base of the skull and upper cervical spine. One hundred patients irradiated by a 3D conformal technique combining photon and proton beams.

To define the prognostic factors for local control and overall survival among 100 consecutive patients with chordoma of the base of skull or upper cervical spine treated by fractionated irradiation combining proton and photon beams. Between December 1993 and August 2002, 100 patients (median age: 53 years [8 - 85], M/F sex ratio: 3/2) were treated by a combination of high-energy photons and protons. The proton component was delivered at the Centre de Protonthérapie d'Orsay (CPO) by a 201 MeV beam. The median total dose delivered to the tumor volume was 67 GyECo. With a median follow-up of 31 months [range: 0 - 87], 25 tumours relapsed locally. The 2- and 4-year local control rates were 86.3% (+/-3.9%) and 53.8% (+/-7.5%), respectively. According to multivariate analysis, at least 95% of the tumor volume encompassed by the 95% isodose (p = 0.048; RR: 3.4 95%CI [1.01 - 11.8]) and a minimal dose delivered into the tumor volume <56 GyECo (p = 0.042; RR: 2.3 95%CI [1.03 - 5.2]) were independent prognostic factors of local control. Ten patients died. The 2- and 5-year overall survival rates were 94.3% (+/-2.5%) and 80.5% (+/-7.2%), respectively. According to multivariate analysis, local tumor control (p = 0.005; RR: 21 95%CI [2.2 - 200]) was a prognostic factor of overall survival. For chordomas of the base of the skull and upper cervical spine treated by surgery and irradiation combining photons and protons, the quality of irradiation, reflected by homogeneity of the dose into the tumor volume, is a major factor of local control. Close attention must be paid to minimize the underdosed areas close to critical organs. The role of surgical resection remains paramount, and a trial of dose escalation would have to consider an increase in the dose to critical organs, especially as current results indicate the low toxicity of this treatment.

Adolescent↗
PubMed2005

[Chemoradiotherapy].

Explore the source record for details and available documents.

Antineoplastic Agents↗
PubMed2005

[Combined radiotherapy and hormone therapy in non metastatic adenocarcinoma of prostate].

Non metastatic adenocarcinoma of prostate can be cured in the vast majority of cases with surgery and/or external or interstitial radiotherapy. Failures are much more frequent when tumours are locally advanced. For this reason, new strategies have been designed, among them combined radiotherapy and hormonotherapy, in most cases with a LHRH analog, neoadjuvant and/or concomitant and/or adjuvant. Analysis of results of recent randomised trials comparing this association and exclusive radiotherapy allows for validating concept of combined radiotherapy and hormono therapy in locally advanced adenocarcinoma of prostate, while many questions should be more clearly answered.

Androgen Antagonists↗
PubMed2004

Clinical complementarities between proton and carbon therapies.

Protons are characterised by low LET, but compared with photons and electrons have an improved physical depth dose distribution. Some indications for protons, i.e., ocular melanoma, chordoma and chondrosarcoma of the base of skull or cervical spine, are now accepted by the radiation oncology community as the treatment of choice. Others are still under evaluation, e.g. meningioma, locally advanced nasopharynx tumours, paediatric tumours. Neutrons have the biological advantage of a high LET, but their distribution of dose is in most cases suboptimal. Despite this, there are radiobiological arguments leading to expect that neutrons might be of some benefit in patients with tumours that are resistant to photons, slowly growing or containing a high proportion of hypoxic cells. There is some clinical evidence or rationale for a potential high LET advantage for locally extensive (I think that the current (jargon) word is extended in English..) salivary gland tumours, locally extensive(extended) prostate carcinoma, slowly growing inoperable soft tissue sarcoma, adenocarcinoma, adenoid cystic carcinoma of the paranasal sinuses, melanoma and rectal carcinoma. Light ions combine the high LET advantage of neutrons and the improved physical depth dose distribution of protons. The opportunity offered by an optimised distribution of dose should open a new era for high-LET particles, especially in deeply situated x-ray resistant tumours, where the use of neutron beams was restricted by the low quality of their depth-dose profiles. Preliminary results are encouraging.

Carbon↗
PubMed2004

Chondrosarcomas of the base of the skull in Ollier's disease or Maffucci's syndrome--three case reports and review of the literature.

Ollier's disease is a rare disease characterized by constitutional bone dysplasia with multiple enchondromas. The combination of haemangioma and chondromatoses is known as Maffucci's syndrome. Malignant degeneration of bone dysplasia into chondrosarcoma is a well-known complication, but a lesion of the base of the skull is exceptional. It is a slowly growing low-grade malignant tumour. Three new cases of chondrosarcoma of the base of the skull occurring in one patient with Marfucci's syndrome and two patients with Ollier's disease are reported and these cases are discussed in the light of the literature. A multidisciplinary approach, comprising surgery and radiotherapy, achieved good results.

Adult↗
PubMed2004

Radiotherapeutic factors in the management of cervical-basal chordomas and chondrosarcomas.

OBJECTIVE: To define prognostic factors for local control and survival in 90 consecutive patients treated by fractionated photon and proton radiation for chordoma or chondrosarcoma of the cranial base and upper cervical spine. METHODS: Between December 1995 and December 2000, 90 patients (median age, 51.3 yr; range, 10-85 yr; male/female ratio, 3:2) were treated by a combination of high-energy photons and protons. Sixty-four patients had a chordoma, and 26 had a chondrosarcoma. The proton component was delivered by the 201-MeV proton beam of the Centre de Protontherapie d'Orsay. The median total dose delivered to the gross tumor volume (GTV) was 67 cobalt Gray equivalents (range, 22-70 cobalt Gray equivalents). RESULTS: With a median follow-up of 34 months (range, 3-74 mo), treatment of 25 tumors failed locally. The 3-year local control rates were 69.2% (+/-6.0%) and 91.6% (+/-8.4%) for chordomas and chondrosarcomas, respectively. According to multivariate analysis, a small tumor volume excluded from the 95% isodose line (P = 0.032; relative risk [RR], 0.098; 95% confidence interval [CI], 0.01-0.81) and a controlled tumor (P = 0.049; RR, 0.19; 95% CI, 0.04-0.99) were independent favorable prognostic factors for overall survival. On multivariate analysis, a high minimum dose (P = 0.02; RR, 2.8; 95% CI, 1.2-6.6), a high tumor control probability (P = 0.02; RR, 3.8; 95% CI, 1.2-12.5), a high dose delivered to 95% of the GTV (P = 0.03; RR, 3.4; 95% CI, 1.15-10.2), a high GTV encompassed by the 90% isodose line (P = 0.01; RR, 3.29; 95% CI, 1.29-8.44), and a small GTV excluded from the 90% isodose line (P = 0.036; RR, 0.4; 95% CI, 0.1-0.9) were independent favorable prognostic factors for local control. CONCLUSION: In chordomas and chondrosarcomas of the cranial base and cervical spine treated by surgical resection and then by high-dose photon and proton irradiation, local control is mainly dependent on the quality of radiation, especially dose uniformity within the GTV. Special attention must be paid to minimize underdosed areas because of the close proximity of critical structures and to redefine and possibly escalate dose constraints to tumor targets in future studies in view of the low toxicity observed to date.

Adolescent↗
PubMed2004

[Radiosurgery of brain metastasis: reflexions, controversies and unanswered questions in 2004].

The quantity of results published since the development of the radiochirurgie does not always lead to consider overall the consequences of the introduction of this treatment into the therapeutic arsenal of the clinician. The role of this treatment in front of the surgery, its association with the whole brain radiation therapy, the impact on the survival of this treatment and the incorporation of the various prognostic factors to the therapeutic decision are some one of the unresolved question. Best indications of radiosurgery concern probably patient with a good performance status, without extra-cranial disease and presenting no more than 4 metastasis. However, in an obviously palliative context, any dogmatism must be avoided. Development of prospective trials is the best solution to well specify the indication of the technique.

Brain Neoplasms↗