Jean-Marc Simon

Effect of dose rate on local control and complications in definitive irradiation of T1-2 squamous cell carcinomas of mobile tongue and floor of mouth with interstitial iridium-192.

From 1971 to 1988, 134 T1 and 145 T2 biopsy-proven squamous cell carcinomas of mobile tongue and floor of mouth were definitively managed by iridium-192. Implantations were performed using either guide gutters or afterloading plastic catheters. The prescribed dose at the reference isodose (85% of the basal dose rate, Paris system) was 60-70 Gy. Total dose was not adjusted to dose rate or tumor volume. Results of the 279 implants have been analysed to look for a possible influence of dose rate on local control and necrosis. Follow-up patients free of local recurrence is 1-180 months with average of 51 months. The 279 tumors were divided in four groups according to dose and dose rate: greater than or equal to 62.5 Gy and greater than or equal to 0.5 Gy/h (n = 130), greater than or equal to 62.5 Gy and less than 0.5 Gy/h (n = 36), less than 62.5 Gy and greater than or equal to 0.5 Gy/h (n = 81), less than 62.5 Gy and less than 0.5 Gy/h (n = 32). The four groups were comparable according to age, sex, tumor diameter and macroscopic aspect. At 5 years, the estimated local control (Kaplan Meier) was 93, 87, 79 and 52%, respectively (dose adjusted to dose rate: p less than 0.001, dose rate adjusted to dose: p less than 0.01, Log-rank); the necrosis rate was 44, 24, 37 and 5%, respectively (dose adjusted to dose rate: p = 0.08, dose rate adjusted to dose: p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Radiosurgery for re-irradiation of brain metastasis: results in 54 patients

PURPOSE To evaluate in terms of probabilities of local-regional control and survival, as well as of treatment-related toxicity, results of radiosurgery for brain metastasis arising in previously irradiated territory. PATIENTS AND METHODS Between January 1994 and March 2000, 54 consecutive patients presenting with 97 metastases relapsing after whole brain radiotherapy (WBRT) were treated with stereotactic radiotherapy. Median interval between the end of WBRT and radiosurgery was 9 months (range 2-70). Median age was 53 years (24-80), and median Karnofski performance status (KPS) 70 (60-100). Forty-seven patients had one radiosurgery, five had two and two had three. Median metastasis diameter and volume were 21 mm (6-59) and 1.2 cc (0.1-95.2), respectively. A Leksell stereotactic head frame (Leksell Model G, Elektra, Instrument, Tucker, GA) was applied under local anesthesia. Irradiation was delivered by a gantry mounted linear accelerator (linacs) (Saturne, General Electric). Median minimal dose delivered to the gross disease was 16.2 Gy (11.8-23), and median maximal dose 21.2 Gy (14- 42). RESULTS Median follow-up was 9 months (1-57). Five metastases recurred. One- and 2-year metastasis local control rates were 91.3 and 84% and 1- and 2-year brain control rates were 65 and 57%, respectively. Six patients died of brain metastasis evolution, and three of leptomeningeal carcinomatosis. One- and 2-year overall survival rates were 31 and 28%, respectively. According to univariate analysis, KPS, RPA class, SIR score and interval between WBRT and radiosurgery were prognostic factors of overall survival and brain free-disease survival. According to multivariate analysis, RPA was an independent factor of overall survival and brain free-disease survival, and the interval between WBRT and radiosurgery longer than 14 months was associated with longer brain free-disease survival. Side effects were minimal, with only two cases of headaches and two of grade 2 alopecia. CONCLUSION Salvage radiosurgery of metastasis recurring after whole brain irradiation is an effective and accurate treatment which could be proposed to patients with a KPS>70 and a primary tumour controlled or indolent. We recommend that a dose not exceeding 14 Gy should be delivered to an isodose representing 70% of the maximal dose since local control observed rate was similar to that previously published in literature with upper dose and side effects were minimal.

Radiosurgery for brain metastasis: impact of CTV on local control

PURPOSE The purpose of the present analysis was to assess whether adding a 1 mm margin to the gross tumour volume (GTV) improves the control rate of brain metastasis treated with radiosurgery (RS). PATIENTS AND METHODS All the patients had one or two brain metastases, 30 mm or less in diameter, and only one isocentre was used for RS. There were 23 females and 38 males. The median age was 54 years (34-76). The median Karnofsky performance status was 80 (60-100). At the time of RS, 23 patients had no evidence of extracranial disease and 38 had a progressive systemic disease. Thirty-eight patients were treated up-front with only RS. Twenty-three patients were treated for relapse or progression more than 2 months after whole brain radiotherapy. From January 1994 to July 1995, clinical target volume (CTV) was equal to GTV without any margin (33 metastases). From August 1995 to August 2000, CTV was defined as GTV plus a 1 mm margin (45 metastases). A dose of 20Gy was prescribed to the isocentre and 14Gy at the margin of CTV. RESULTS The median follow-up was 10.5 months (1-45). The mean minimum dose delivered to GTV was 14.6Gy in the group without a margin and 16.8Gy in the group with a 1 mm margin (P<0.0001). The response of 11 metastases was never assessed because patients died before the first follow-up. Ten metastases recurred, eight in the group treated without a margin and two in the group treated with a 1 mm margin (P=0.01). Two-year local control rates were 50.7+/-12.7% and 89.7+/-7.4% (P=0.008), respectively. Univariate analysis showed that the treatment group (P=0.008) and the tumour volume (P=0.009) were prognostic factors for local control. In multivariate analysis, only the treatment group with a 1 mm margin was an independent prognostic factor for local control (P=0.04, RR: 5.8, 95% CI [1.08-31.13]). There were no significant differences, either in overall survival rate or in early and late side effects, between the two groups. CONCLUSION Adding a 1 mm margin to the GTV in patients treated with RS significantly improves the probability of metastasis control without increasing the side effects.

Treatment of Malignant Gliomas in the Elderly

The benefit of standard treatment of malignant glioma in older patients is debated. In order to assess the effect of a combination of surgery, radiotherapy and chemotherapy on survival of elderly patients with high grade gliomas, 30 consecutive patients older than 70 years with malignant supratentorial gliomas were studied between 9/93 and 9/96. Median age was 73 years (70–79). The mean Karnofsky performance status (KPS) was 66 (30–100). Patients underwent maximum possible surgery, followed by a course of radiotherapy (45 Gy/25 fractions/5 weeks) with 3 or 4 orthogonal beams and a 2 cm margin around the tumor bed. The administration of chemotherapy was left at the discretion of the responsible physician and 12 patients received reduced dose nitrosourea-based chemotherapy. The overall median survival was 36 weeks. The median time to progression was 26 weeks. Three months after surgery, 26 patients were alive, 5 were in complete response, 2 in partial response and 10 were stabilized. Pre-radiotherapy KPS was the only significant prognostic factor with a median survival of 40 weeks in patients with KPS ≥70 and 25 weeks when KPS was >70 (logrank test, p=0.05). In responding and stable patients (57% of the group) the median KPS was 68 and 66 at 1 and 3 months after the completion of radiotherapy. There was no case of radiotherapy-induced dementia with this regimen. Four out of 12 patients who received chemotherapy, experienced WHO grade 3/4 hematotoxicity.This study suggest that some patients older than 70 years with KPS ≥70 may benefit from the treatment of malignant gliomas with surgery followed by reduced dose of limited field radiotherapy. Further studies are needed to define the most appropriate dose of radiotherapy and to evaluate further the risk/benefit ratio of a reduced dose chemotherapy in this population.

Three irradiation treatment options including radiosurgery for brain metastases from primary lung cancer

PURPOSE To determine local control and survival rates in 92 patients with 145 brain metastases treated with three options of radiotherapy including stereotactic radiosurgery (SR). METHODS Between July 1994 and August 2002, 92 consecutive patients with 145 metastases were treated with a SR, 34 with initially SR alone, 22 initially with an association of whole-brain radiotherapy (WBRT) and 36 with SR alone for recurrent new brain metastasis after WBRT. At time of treatment, extracranial disease was controlled in 46 (50%) and uncontrolled in 46 (50%). Pathologies were adenocarcinoma in 54 cases (59%), squamous cell carcinoma in 14 cases (15%), small cell carcinoma in 10 cases (11%) and miscellaneous in 14 cases (15%). All patients underwent only one treatment fraction for 1 or 2 metastases in 73 cases (83%) and for more than 2 metastases for the others. RESULTS The characteristics of patients and metastases in the group treated initially with SR alone and in the group treated initially with WBRT+SR were comparable. Median follow-up was 29 months (18-36). Overall, the median and the 1- and 2-year rates of overall survival were, respectively, 9 months, 37 and 20%. A controlled extracranial disease, a high Karnofsky index and a low number of metastasis were independent prognostic factor of overall survival, respectively, HR 0.53 (95% CI 0.31-0.90, P=0.01), HR 0.95 (95% CI 0.92-0.97, P=0.0002), and HR 0.48 (95% CI 0.25-0.90, P=0.02). Thirteen metastases were not controlled (9%). Six-month and 1-year local control rate were, respectively, 93 and 86%. High delivered dose was an independent prognostic factor of local control, HR 0.41 (95% CI 0.18-0.95, P=0.03). A controlled extracranial disease was favourable independent prognostic factor of brain free-disease free survival, HR 0.47 (95% CI 0.2-0.98, P=0.04). Although there was a trend of a better local control, overall and brain disease free survivals rates in the WBRT+SR group compared to SR alone one, the difference were not statistically different. CONCLUSION Local control and survival rates are acceptable for a palliative treatment for the three option of treatment. In this series, the number of patients is not enough great to conclude to the necessity of the association of WBRT to SR. Re-irradiation is a safe treatment after new metastases appeared in previously irradiated area.

Calculating thermodynamic properties from fluctuations at small scales.

We show how density and energy fluctuations of small nonperiodic systems embedded in a reservoir can be used to determine macroscopic thermodynamic properties like the enthalpy density and the thermodynamic correction factor. For mixtures, the same formalism leads to a very convenient method to obtain so-called total correlation function integrals, also often referred to as Kirkwood-Buff integrals. Using finite size scaling, the properties obtained for small systems can be extrapolated to the macroscopic system limit provided that the system is sufficiently far from the critical point. As derived in our previous work (Chem. Phys. Lett. 2011, 504, 199-201), the finite size scaling is significant and depends on 1/L, where L is the length of the small system in one dimension. By considering a reservoir with an ensemble of embedded small systems, we can use the scaling arising from surface effects to determine properties for macroscopic systems by extrapolation. We demonstrate this method for the WCA and LJ fluids, as well a for a heterogeneous system, i.e., argon adsorbed in silicalite-1 zeolite.

LINAC radiosurgery for brain metastasis of renal cell carcinoma

The purpose of the study was to evaluate the efficacy and toxicity of stereotactic radiotherapy in the treatment of the brain metastasis of renal cell carcinoma. From 1994 to 2001, 28 patients presenting with 65 metastases of renal cell cancer were treated by radiosurgery. Median age was 55 years (35-75), and median Karnofski performance status ranges between 50 and 100. Seven patients had received whole brain radiotherapy (WBRT) before radiosurgery. Twelve patients were treated by radiosurgery for 1 metastasis, 5 patients for two metastases and 6 for three, and 5 for more than three metastases. One procedure was performed in 22 patients and, 2 or 3 procedures for 6 patients. Median metastasis diameter was 19 mm (5-55 mm). Median metastasis volume was 1.28 cc (0.02-28 cc). Irradiation was delivered by linear accelerator. Median minimal dose (on the 70% isodose) was 14.7 Gy (10.8 Gy, 19.5 Gy), median maximal dose (at the isocenter) 20.5 Gy (14.3 Gy, 39.6 Gy). Median follow-up was 14 months (1-33). Two metastases progressed (3%), 2 and 12 months after radiosurgery. Overall, crude local control rate was 97% and 3-, 6- and 12-month local control rates were 98% +/- 2%, 98% +/- 2%, and 93% +/- 5%, respectively. In univariate analysis, no prognostic factor of local control was retrieved. Median brain disease-free survival was 25 months after RS. the 3-, 6- and 12-month distant brain control rates were 91% +/- 4%, 91% +/- 4%, and 70% +/- 12%, respectively. Median survival duration was 11 months. The 3-, 6-, 12- and 24-month overall survival rates were 82% +/- 7%, 67% +/- 9%, 48% +/- 10%, and 33% +/- 10%, respectively. According to univariate analysis, only site of metastasis was overall survival prognostic factor. Radiosurgery for brain metastasis of renal cell carcinoma is an effective and accurate treatment. The use of radiosurgery alone is an appropriate management strategy for many patients with brain metastasis of renal cell carcinoma. Radiosurgery is efficient even after development of new metastasis appearing after WBRT.

Monte Carlo versus molecular dynamics simulations in heterogeneous systems: an application to the n-pentane liquid-vapor interface.

The Monte Carlo (MC) and molecular dynamics (MD) methodologies are now well established for computing equilibrium properties in homogeneous fluids. This is not yet the case for the direct simulation of two-phase systems, which exhibit nonuniformity of the density distribution across the interface. We have performed direct MC and MD simulations of the liquid-gas interface of n-pentane using a standard force-field model. We obtained density and pressure components profiles along the direction normal to the interface that can be very different, depending on the truncation and long range correction strategies. We discuss the influence on predicted properties of different potential truncation schemes implemented in both MC and MD simulations. We show that the MD and MC profiles can be made in agreement by using a Lennard-Jones potential truncated via a polynomial function that makes the first and second derivatives of the potential continuous at the cutoff distance. In this case however, the predicted thermodynamic properties (phase envelope, surface tension) deviate from experiments, because of the changes made in the potential. A further readjustment of the potential parameters is needed if one wants to use this method. We conclude that a straightforward use of bulk phase force fields in MD simulations may lead to some physical inconsistencies when computing interfacial properties.

Influence of dose rate on local control of breast carcinoma treated by external beam irradiation plus iridium 192 implant.

From 1971 to 1983, 20 T1, 267 T2, and 53 T3 biopsy-proven adenocarcinomas of breast were definitively managed by radiotherapy. The breast and regional nodes received 45 Gy of 60Co irradiation in 25 fractions over 5 weeks (45 Gy/25/5 wks). Electrons were used to deliver a further 15 Gy/7/1.5 weeks to the internal mammary chain and 25 Gy/11/2.5 weeks to the lower axilla. The primary tumor was boosted by Iridium 192 implant for a further 37 Gy prescribed at 85% of the basal dose rate (Paris system). Rigid needles were secured by templates in single plane (58/398) or double plane (340/398) geometry. Results of the 340 two-plane implants have been analyzed to look for a possible influence of dose rate on local control. Follow-up for patients free of local recurrence is 4-204 months (median: 92 months). The 340 tumors were divided into three groups according to dose rate: 0.32-0.49 Gy/hr (n = 95), 0.50-0.59 Gy/hr (n = 120), and 0.60-0.90 Gy/hr (n = 125). The three groups are statistically comparable according to age, tumor size, mean 60Co dose, mean Iridium dose, overall treatment time, and follow-up. The local failure rate in the three groups is 27% (26/95), 20% (24/120), and 13% (16/125) (p less than 0.03, Chi square). At 15 years the estimated local control (Kaplan Meier) is 60%, 72%, and 84% (p less than 0.02, Logrank), respectively. This analysis indicates that there is a significant effect of dose rate on local control for carcinoma of the breast treated by combined external beam (45 Gy) plus Iridium 192 implantation (37 Gy). To maximize local control the authors recommend an implant dose rate of greater than or equal to 0.6 Gy/hr.