Quality of Randomized Controlled Trials Reporting in the Treatment of Adult Patients with High-Grade Gliomas

BACKGROUND

The randomized controlled trial (RCT) is the gold standard to objectively assess the effect of treatments. To help improve the quality of RCTs, experts established a list of recommendations, the CONsolidated Standards of Reporting Trials (CONSORT) Statement. In this study, we evaluated the implementation of the CONSORT Statement in the field of high-grade gliomas in adult patients and looked for criteria associated with higher quality of RCTs.

MATERIALS AND METHODS

We searched all high-grade gliomas RCTs published in PubMed between January 1990 and December 2016. The quality of these RCTs was assessed by completing a modified CONSORT Score (CS).

RESULTS

Ninety-six published RCTs were identified. The median CS was 19.5 on a scale of 0-33. Items were not equally reported. Items regarding the method of randomization or the blinding were reported in less than 25% of RCTs. However, the CS has constantly improved over the years. Before the implementation of the CONSORT Statement in 1996, the median CS was 13, whereas it was 17 for the period 1996-2004 and 22 after 2005. A higher CS was observed when RCTs were published in a journal with an impact factor above 10 (p < .001) or after 2010 (p = .001), when the primary outcome was clearly defined (p < .001) and for RCTs that enrolled more than 200 patients (p = .004).

CONCLUSION

Although there has been a steady improvement in the CS over the years in the field of high-grade gliomas, a major effort must be made in the reporting methods for randomization and blinding.

IMPLICATIONS FOR PRACTICE

This study showed that the quality of reporting of randomized control trials (RCTs) concerning the treatment of high-grade gliomas is poor. Factors associated with a better quality of reports were identified and should be incorporated into the design of future RCTs. When clinicians read the results of RCTs, they should be aware of the possible inadequate reporting from these trials and take it into account for the management of their patients. This study identifies how RCTs can be improved in their reporting but also in their design, in order to advance care for patients with high-grade gliomas in the future.

A French national breast and thyroid cancer screening programme for survivors of childhood, adolescent and young adult (CAYA) cancers - DeNaCaPST programme

Background

Survival of childhood, adolescent and young adult (CAYA) cancers has increased with progress in the management of the treatments and has reached more than 80% at 5 years. Nevertheless, these survivors are at great risk of second cancers and non-malignant co-morbidities in later life. DeNaCaPST is a non-interventional study whose aim is to organize a national screening for thyroid cancer and breast cancer in survivors of CAYA cancers. It will study the compliance with international recommendations, with the aim, regarding a breast screening programme, of offering for every woman living in France, at equal risk, an equal screening.

Method

DeNaCaPST trial is coordinated by the INSERM 1018 unit in cooperation with the LEA (French Childhood Cancer Survivor Study for Leukaemia) study’s coordinators, the long term follow up committee and the paediatric radiation committee of the SFCE (French Society of Childhood Cancers).

A total of 35 centres spread across metropolitan France and la Reunion will participate. FCCSS (French Childhood Cancer Survivor Study), LEA and central registry will be interrogated to identify eligible patients. To participate, centers agreed to perform a complete “long-term follow-up consultations” according to good clinical practice and the guidelines of the SFCE (French Society of Children Cancers).

Discussion

As survival has greatly improved in childhood cancers, detection of therapy-related malignancies has become a priority even if new radiation techniques will lead to better protection for organs at risk. International guidelines have been put in place because of the evidence for increased lifetime risk of breast and thyroid cancer. DeNaCaPST is based on these international recommendations but it is important to recognize that they are based on expert consensus opinion and are supported by neither nonrandomized observational studies nor prospective randomized trials in this specific population. Over-diagnosis is a phenomenon inherent in any screening program and therefore such programs must be evaluated.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3318-1) contains supplementary material, which is available to authorized users.

Salvage prostate re-irradiation using high-dose-rate brachytherapy or focal stereotactic body radiotherapy for local recurrence after definitive radiation therapy

Background

Optimal management of locally recurrent prostate cancer after definitive radiation therapy is still challenging. With the development of highly accurate radiotherapy devices, prostate salvage re-irradiation might generate lower toxicity rates than classical salvage therapies. We retrospectively evaluated the toxicity and the feasibility of a prostate re-irradiation after definitive radiation therapy failure. Two modalities were investigated: high-dose-rate brachytherapy (HDRB) on whole prostate gland and focal stereotactic radiotherapy (SBRT) using CyberKnife® linac.

Methods

Between 2011 and 2015, 28 patients with imaged and/or biopsy-proven intra-prostatic recurrence of cancer after definitive radiation therapy underwent a salvage re-irradiation using HDRB (n = 10) or focal SBRT (n = 18). The schedule of re-irradiation was 35 Gy in 5 fractions.

Biological response (defined as post-salvage radiation PSA variation) and biochemical no-evidence of disease (bNED) were evaluated in the whole cohort. For patients who had a positive biological response after salvage radiation, biochemical recurrence (BCR) and survival after salvage radiotherapy were evaluated. Post-salvage toxicities were assessed according to the Common Terminology Criteria for Adverse Events (CTCAE) v4.03 and were compared to baseline status.

Results

Within a median follow-up of 22.5 months (IQR = 8–42), 9 (90%) patients experienced a positive biological response after salvage HDRB and 5 (50%) remained bNED at the end of the follow-up. Among patients who initially responded to salvage HDRB, the BCR rate was 44.4% after a median interval of 19.5 months (IQR = 11.5–26). Only one patient experienced a transient grade 3 urinary complication.

In the SBRT group, the median follow-up was 14.5 months (IQR = 7–23) and 10 (55.6%) out of the 18 patients remained bNED. Among the 15 patients who initially responded to salvage SBRT, 5 (33.3%) experienced a BCR. One patient experienced a transient grade 4 urinary complication.

At the end of the follow-up, all evaluated patients had a urinary status grade variation ≤ +1 grade. No grade 3–4 digestive toxicity was observed.

Conclusions

Salvage prostate re-irradiation for locally recurrent cancer is feasible and generate low toxicities rates when using with HDRB or focal SBRT. However, further investigations are necessary to confirm these findings and to determine predictive features for patients who might benefit from such an approach.

The right to be forgotten: a change in access to insurance and loans after childhood cancer?

PURPOSE

Access to insurance for a loan or a mortgage is an important issue for childhood cancer survivors. The aim of this study was to describe difficulties experienced by adult survivors.

METHODS

A total of 1920 survivors treated before the age of 18 in five French cancer centers responded to a questionnaire in 2010. Survivors who had tried to obtain a loan were asked if they had experienced difficulties, which were defined as experiencing rejection, higher premiums, or exclusions. The questionnaire investigated health problems related to the circulatory, respiratory, digestive, urinary, endocrine, hormonal, and nervous systems. Second tumors, diabetes mellitus, cardiac disease, and stroke were ascertained from a physician's report or medical records. Multivariable analyses were conducted to identify the characteristics of survivors reporting difficulties.

RESULTS

Difficulties were experienced by 10.4% of those who had tried to obtain a small loan (n = 787) and by 30.1% of those who had tried to obtain a home loan (n = 909). Disclosure of childhood cancer to the insurer and amputation surgery were negatively associated with insurance accessibility, even when controlling for age, gender, education, health-related unemployment, familial situation, and severe or life-threatening conditions such as cardiovascular diseases, second cancers, or diabetes.

CONCLUSION

This study showed that the financial burden of cancer can extend decades after diagnosis.

IMPLICATIONS FOR CANCER SURVIVORS

Thanks to a 2016 law, French cancer survivors no longer have to disclose their cancer to insurers after a fixed number of years. This law will probably lessen the socioeconomic burden of cancer.

Impact of dose calculation models on radiotherapy outcomes and quality adjusted life years for lung cancer treatment: do we need to measure radiotherapy outcomes to tune the radiobiological parameters of a normal tissue complication probability model?

BACKGROUND

The equivalent uniform dose (EUD) radiobiological model can be applied for lung cancer treatment plans to estimate the tumor control probability (TCP) and the normal tissue complication probability (NTCP) using different dose calculation models. Then, based on the different calculated doses, the quality adjusted life years (QALY) score can be assessed versus the uncomplicated tumor control probability (UTCP) concept in order to predict the overall outcome of the different treatment plans.

METHODS

Nine lung cancer cases were included in this study. For the each patient, two treatments plans were generated. The doses were calculated respectively from pencil beam model, as pencil beam convolution (PBC) turning on 1D density correction with Modified Batho's (MB) method, and point kernel model as anisotropic analytical algorithm (AAA) using exactly the same prescribed dose, normalized to 100% at isocentre point inside the target and beam arrangements. The radiotherapy outcomes and QALY were compared. The bootstrap method was used to improve the 95% confidence intervals (95% CI) estimation. Wilcoxon paired test was used to calculate P value.

RESULTS

Compared to AAA considered as more realistic, the PBC_MB overestimated the TCP while underestimating NTCP, P<0.05. Thus the UTCP and the QALY score were also overestimated.

CONCLUSIONS

To correlate measured QALY's obtained from the follow-up of the patients with calculated QALY from DVH metrics, the more accurate dose calculation models should be first integrated in clinical use. Second, clinically measured outcomes are necessary to tune the parameters of the NTCP model used to link the treatment outcome with the QALY. Only after these two steps, the comparison and the ranking of different radiotherapy plans would be possible, avoiding over/under estimation of QALY and any other clinic-biological estimates.

Re-irradiation of recurrent pediatric ependymoma: modalities and outcomes: a twenty-year survey

Background

Standard treatment for recurrent ependymomas is not defined. Re- irradiation has been proposed but its modalities and results are still to be explored.

Patients and methods

From June 1994 to December 2013, 32 pediatric patients with ependymoma were re-irradiated for local (n = 15) or metastatic (n = 17) relapses. Files were reviewed retrospectively.

Results

Local relapses were treated with hypofractionated focal radiotherapy (hypoFFRT) (n = 8) or focal fractionated radiotherapy (FFRT) (n = 7). Metastatic relapses were treated with hypoFFRT (n = 3), FFRT (n = 3), spinal radiotherapy (n = 4) and craniospinal irradiation (CSI) (n = 7). Median PFS and OS after re-irradiation were 1.2 and 3.5 years respectively with a median follow-up of 2.1 years (0.2–11.4). For local relapses, median PFS was 2.5 years for patients treated with hypoFFRT versus 1.2 years for patients treated with FFRT (p = 0.2). For metastatic relapses, median PFS was 0.7 years for patients treated with focal radiotherapy (hypoFFRT, FFRT, spinal radiotherapy) versus 6.8 years for patients treated with CSI (p = 0.073). 15 patients achieved greater PFS after second radiotherapy (RT2) than after first radiotherapy (RT1). 27 patients (84 %) had surgery before re-irradiation. PFS was better for patients with GTR before RT2 (14.7 vs 6.7 months) (p = 0.05). 5 patients developed radionecrosis; only one required corticosteroids.

Conclusion

Re-irradiation at relapse is a safe, feasible and potentially curative treatment. Metastatic relapse may require CSI even when isolated and re-operated. For local relapses, considering conflicting results in the literature, a randomized trial is warranted to explore fractionated focal radiotherapy versus hypofractionated focal irradiation.

Cardiac Diseases Following Childhood Cancer Treatment

Background—

Cardiac disease (CD) is one of the major side effects of childhood cancer therapy, but until now little has been known about the relationship between the heart radiation dose (HRD) received during childhood and the risk of CD.

Methods and Results—

The cohort comprised 3162 5-year survivors of childhood cancer. Chemotherapy information was collected and HRD was estimated. There were 347 CDs in 234 patients, 156 of them were rated grade ≥3. Cox and Poisson regression models were used. The cumulative incidence of any type of CD at 40 years of age was 11.0% (95% confidence interval [CI], 9.5–12.7) and 7·4% (95% CI, 6.2–8.9) when only the CDs of grade ≥3 were considered. In comparison with patients who received no anthracycline and either no radiotherapy or an HRD<0·1Gy, the risk was multiplied by 18·4 (95% CI, 7.1–48.0) in patients who had received anthracycline and no radiotherapy or a HRD <0.1Gy, by 60.4 (95% CI, 22.4–163.0) in those who had received no anthracycline and an HRD≥30Gy, and 61.5 (95% CI, 19.6–192.8) in those who had received both anthracycline and an HRD≥30Gy.

Conclusions—

Survivors of childhood cancers treated with radiotherapy and anthracycline run a high dose-dependent risk of developing CD. CDs develop earlier in patients treated with anthracycline than in those treated without it.

Thyroid Radiation Dose and Other Risk Factors of Thyroid Carcinoma Following Childhood Cancer

CONTEXT

Thyroid carcinoma is a frequent complication of childhood cancer radiotherapy. The dose response to thyroid radiation dose is now well established, but the potential modifier effect of other factors requires additional investigation.

OBJECTIVE

This study aimed to investigate the role of potential modifiers of the dose response.

DESIGN

We followed a cohort of 4338 5-year survivors of solid childhood cancer treated before 1986 over an average of 27 years. The dose received by the thyroid gland and some other anatomical sites during radiotherapy was estimated after reconstruction of the actual conditions in which irradiation was delivered.

RESULTS

Fifty-five patients developed thyroid carcinoma. The risk of thyroid carcinoma increased with a radiation dose to the thyroid of up to two tenths of Gy, then leveled off for higher doses. When taking into account the thyroid radiation dose, a surgical or radiological splenectomy (>20 Gy to the spleen) increased thyroid cancer risk (relative risk [RR] = 2.3; 95% confidence interval [CI], 1.3-4.0), high radiation doses (>5 Gy) to pituitary gland lowered this risk (RR = 0.2; 95% CI, 0.1-0.6). Patients who received nitrosourea chemotherapy had a 6.6-fold (95% CI, 2.5-15.7) higher risk than those who did not. The excess RR per Gy of radiation to the thyroid was 4.7 (95% CI, 1.7-22.6). It was 7.6 (95% CI, 1.6-33.3) if body mass index at time of interview was equal or higher than 25 kg/m(2), and 4.1 (95% CI, 0.9-17.7) if not (P for interaction = .1).

CONCLUSION

Predicting thyroid cancer risk following childhood cancer radiation therapy probably requires the assessment of more than just the radiation dose to the thyroid. Chemotherapy, splenectomy, radiation dose to pituitary gland, and obesity also play a role.

Risk of second bone sarcoma following childhood cancer: role of radiation therapy treatment

Bone sarcoma as a second malignancy is rare but highly fatal. The present knowledge about radiation-absorbed organ dose-response is insufficient to predict the risks induced by radiation therapy techniques. The objective of the present study was to assess the treatment-induced risk for bone sarcoma following a childhood cancer and particularly the related risk of radiotherapy. Therefore, a retrospective cohort of 4,171 survivors of a solid childhood cancer treated between 1942 and 1986 in France and Britain has been followed prospectively. We collected detailed information on treatments received during childhood cancer. Additionally, an innovative methodology has been developed to evaluate the dose-response relationship between bone sarcoma and radiation dose throughout this cohort. The median follow-up was 26 years, and 39 patients had developed bone sarcoma. It was found that the overall incidence was 45-fold higher [standardized incidence ratio 44.8, 95 % confidence interval (CI) 31.0-59.8] than expected from the general population, and the absolute excess risk was 35.1 per 100,000 person-years (95 % CI 24.0-47.1). The risk of bone sarcoma increased slowly up to a cumulative radiation organ absorbed dose of 15 Gy [hazard ratio (HR) = 8.2, 95 % CI 1.6-42.9] and then strongly increased for higher radiation doses (HR for 30 Gy or more 117.9, 95 % CI 36.5-380.6), compared with patients not treated with radiotherapy. A linear model with an excess relative risk per Gy of 1.77 (95 % CI 0.6213-5.935) provided a close fit to the data. These findings have important therapeutic implications: Lowering the radiation dose to the bones should reduce the incidence of secondary bone sarcomas. Other therapeutic solutions should be preferred to radiotherapy in bone sarcoma-sensitive areas.

Multi institutional phase II study of concomitant stereotactic reirradiation and cetuximab for recurrent head and neck cancer

PURPOSE

Recurrent head and neck cancer is associated to a poor survival prognosis. A high toxicity rate is demonstrated when surgery and/or radiotherapy and/or chemotherapy are combined. Furthermore, the duration of treatment is often not ethically compatible with the expected survival (median survival<1year). Normal tissues tolerance limits the use of reirradiation and stereotactic body radiotherapy (SBRT) could offer precise irradiation while sparing healthy tissues. After completion of a feasibility study, results of a multicentric study (Lille, Nancy & Nice) using SBRT with cetuximab are reported. The aim of the study was to deliver non toxic short course SBRT (2weeks) in order to get the same local control as the one demonstrated with longer protocols.

METHODS AND MATERIALS

Patients with inoperable recurrent, or new primary tumor in a previously irradiated area, were included (WHO<3). Reirradiation (RT) dose was 36Gy in six fractions of 6Gy to the 85% isodose line covering 95% of the PTV with 5 injections of concomitant cetuximab (CT). All patients had previous radiotherapy, 85% had previous surgery and 48% previous chemotherapy.

RESULTS

Between 11/2007 and 08/2010, 60 were included (46 men and 14 women), 56 received CT+RT, 3 were not treated and 1 received only CT. Median age was 60 (42-87)) and all 56 patients had squamous carcinoma and received concomitant cetuximab. Mean time between previous radiotherapy and the start of SBRT was 38months. Cutaneous toxicity was observed for 41 patients. There was one toxic death from hemorrhage and denutrition. Median follow-up was 11.4months. At 3months, response rate was 58.4% (95% CI: 43.2-72.4%) and disease control rate was 91.7% (95% CI: 80.0-97.7%). The one-year OS rate was 47.5% (95% CI: 30.8-62.4).

CONCLUSION

These results suggest that short SBRT with cetuximab is an effective salvage treatment with good response rate in this poor prognosis population with previously irradiated HNC. Treatment is feasible and, with appropriate care to limiting critical structure, acute toxicities are acceptable. This combination may be the reference treatment is this population.

Cisplatin-docetaxel induction plus concurrent 3-D conformal radiotherapy and weekly chemotherapy for locally advanced non-small cell lung cancer patients: a phase II trial

Concurrent chemoradiotherapy (CHRT) is the standard of care for unresectable locally advanced stage III non-small cell lung cancer. However, the optimal combination remains unclear. The aim of this study was to evaluate the efficacy of 2 induction chemotherapy cycles (days 1 and 22) with docetaxel 75 mg/m(2) and cisplatin 75 mg/m(2) followed by concurrent chemotherapy (weekly docetaxel-cisplatin, 20 mg/m(2)) and 3-D conformal radiotherapy for 6 weeks (66 Gy/5 fractions per week/2 Gy per fraction). The primary endpoint was the response rate. Secondary objectives were toxicity, time to progression, and overall survival. Forty-four patients were included and 40 were eligible. The mean age was 60.5 years (range 40.7-72.1), and 75% had stage IIIB disease. Six patients underwent complete R0 resection including 2 pathologic complete responses after a planned intermediate evaluation. Thirty-three patients completed CHRT. The objective response rate was 65% (95% CI 50.2-79.8). Grade 3-4 hematologic and digestive toxicities were observed mainly during the induction phase. Grade 3 esophagitis (5%) was experienced during CHRT. With a median follow-up of 38.7 months, the median progression-free survival was 28.3 months (95% CI 11.0-35.0) and the median survival rate was 31.4 months. Cisplatin-docetaxel induction followed by concurrent 3-D conformal radiotherapy and weekly chemotherapy is a feasible protocol associated with a promising response rate and acceptable toxicity.

Cyberknife radiosurgery for focal paravertebral recurrence after radical pleurectomy/decortication in malignant pleural mesothelioma

We present a case of malignant pleural mesothelioma with focal relapse in the Azygos arch region after radical pleurectomy/decortication and adjuvant chemotherapy. Tumour recurrence was successfully treated by Cyberknife radiosurgery (70 Gy in five fractions). Patient remains disease-free at 40 months without any other treatment.

Extrapolating glioma invasion margin in brain magnetic resonance images: suggesting new irradiation margins

Radiotherapy for brain glioma treatment relies on magnetic resonance (MR) and computed tomography (CT) images. These images provide information on the spatial extent of the tumor, but can only visualize parts of the tumor where cancerous cells are dense enough, masking the low density infiltration. In radiotherapy, a 2 m constant margin around the tumor is taken to account for this uncertainty. This approach however, does not consider the growth dynamics of gliomas, particularly the differential motility of tumor cells in the white and in the gray matter. In this article, we propose a novel method for estimating the full extent of the tumor infiltration starting from its visible mass in the patients' MR images. This estimation problem is a time independent problem where we do not have information about the temporal evolution of the pathology nor its initial conditions. Based on the reaction-diffusion models widely used in the literature, we derive a method to solve this extrapolation problem. Later, we use this formulation to tailor new tumor specific variable irradiation margins. We perform geometrical comparisons between the conventional constant and the proposed variable margins through determining the amount of targeted tumor cells and healthy tissue in the case of synthetic tumors. Results of these experiments suggest that the variable margin could be more effective at targeting cancerous cells and preserving healthy tissue.

Diplopia as the first symptom of an aggressive metastatic rectal stromal tumor

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms, and metastatic disease is present at diagnosis in about 50%. Most common metastatic sites are the liver, the lungs, and the peritoneum. Bony metastases are uncommon and of unknown prognosis.

CASE REPORT

A 57-year-old man presented with diplopia due to a clival metastastic lesion from an asymptomatic rectal stromal tumor. This patient also had liver and vertebral metastases. Treatment with imatinib, a tyrosine kinase inhibitor, led to a partial response of the primary tumor and hepatic metastasis, but the patient developed aggressive bone metastases that proved refractory to 3 different tyrosine kinase inhibitors.

CONCLUSION

Different drug distribution or different mutation patterns of key prognostic receptors (e.g. cKIT receptor) in bone and soft tissues may explain the unusually aggressive pattern of these bony metastases of a GIST. Pharmacodynamic and molecular investigations are warranted to check these hypotheses.

Robotic stereotactic radioablation concomitant with neo-adjuvant chemotherapy for breast tumors

PURPOSE

Robotic stereotactic radioablation (RSR) allows stereotactic irradiation of thoracic tumors; however, it has never been used for breast tumors and may have a real potential. We conducted a Phase I study, including neoadjuvant chemotherapy (NACT), a two-level dose-escalation study (6.5 Gy x 3 fractions and 7.5 Gy x 3 fractions) using RSR and breast-conserving surgery followed by conventional radiotherapy.

MATERIALS AND METHODS

To define toxicity, we performed a dermatologic exam (DE) including clinical examination by two independent observers and technical examination by colorimetry, dermoscopy, and skin ultrasound. DE was performed before NACT (DE0), at 36 days (DE1), at 56 days (DE2), after the NACT treatment onset, and before surgery (DE3). Surgery was performed 4-8 weeks after the last chemotherapy session. A pathologic examination was also performed.

RESULTS

There were two clinical complete responses and four clinical partial responses at D56 and D85. Maximum tolerable dose was not reached. All patients tolerated RSR with no fatigue; 2 patients presented with mild pain after the third fraction of the treatment. There was no significant toxicity measured with ultrasound and dermoscopy tests. Postoperative irradiation (50 Gy) has been delivered without toxicity.

CONCLUSION

The study showed the feasibility of irradiation with RSR combined with chemotherapy and surgery for breast tumors. There was no skin toxicity at a dose of 19.5 Gy or 22.5 Gy delivered in three fractions combined with chemotherapy. Lack of toxicity suggested that the dose could be increased further. Pathologic response was acceptable.

CYBERKNIFE STEREOTACTIC RADIOTHERAPY FOR SPINAL TUMORS

OBJECTIVE

For para- and intraspinal tumors, precise spinal cord delineation is critical for CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiotherapy. We evaluated whether computed tomographic (CT) myelography is superior to magnetic resonance imaging (MRI) for accurate spinal cord delineation. Treatment parameters and short-term outcome and toxicity are also presented.

METHODS

The planning CT scan, the gadolinium-enhanced, T1-weighted, 3-dimensional (3D) fast imaging employing steady-state acquisition MRI scan, and the CT myelogram were fused before volume-of-interest delineation. The planning target volume margin was less than 1 mm using the Xsight Spine tracking system (Accuray). We present data from 11 heavily pretreated patients who underwent CyberKnife stereotactic radiosurgery between November 2006 and January 2008.

RESULTS

Spatial resolution was 0.46 and 0.93 mm/pixel for CT myelography and 3D-fast imaging employing steady-state acquisition MRI, respectively. The contrast between cerebrospinal fluid and spinal cord was excellent with CT myelography. A transient postmyelography headache occurred in 1 patient. The mean gross tumor volume was 51.1 mL. The mean prescribed dose was 34 Gy in 4 fractions (range, 2–7 fractions) with 147 beams (range, 79–232 beams) to the 75% reference isodose line (range, 68–80%), covering 95% (range, 86–99%) of the gross tumor volume with a mean conformity index of 1.4 (range, 1.1–1.8). No short-term toxicity on the spinal cord was noted at 1- to 6-months of follow-up.

CONCLUSION

CT myelography was more accurate for spinal cord delineation than 3D-fast imaging employing steady-state acquisition MRI (used for its myelographic effect), particularly in the presence of ferromagnetic artifacts in heavily pretreated patients or in patients with severe spinal compression. Because other MRI sequences (T2 and gadolinium-enhanced T1) provide excellent tumor characterization, we suggest trimodality imaging for spinal tumor treatment to yield submillimetric delineation accuracy. Combined with CyberKnife technology, CT myelography can improve the feasibility of dose escalation or reirradiation of spinal tumors in selected patients, thereby increasing local control while avoiding myelopathy. Further follow-up and prospective studies are warranted.

Biocomputing: numerical simulation of glioblastoma growth using diffusion tensor imaging

Glioblastoma multiforma (GBM) is one of the most aggressive tumors of the central nervous system. It can be represented by two components: a proliferative component with a mass effect on brain structures and an invasive component. GBM has a distinct pattern of spread showing a preferential growth in the white fiber direction for the invasive component. By using the architecture of white matter fibers, we propose a new model to simulate the growth of GBM. This architecture is estimated by diffusion tensor imaging in order to determine the preferred direction for the diffusion component. It is then coupled with a mechanical component. To set up our growth model, we make a brain atlas including brain structures with a distinct response to tumor aggressiveness, white fiber diffusion tensor information and elasticity. In this atlas, we introduce a virtual GBM with a mechanical component coupled with a diffusion component. These two components are complementary, and can be tuned independently. Then, we tune the parameter set of our model with an MRI patient. We have compared simulated growth (initialized with the MRI patient) with observed growth six months later. The average and the odd ratio of image difference between observed and simulated images are computed. Displacements of reference points are compared to those simulated by the model. The results of our simulation have shown a good correlation with tumor growth, as observed on an MRI patient. Different tumor aggressiveness can also be simulated by tuning additional parameters. This work has demonstrated that modeling the complex behavior of brain tumors is feasible and will account for further validation of this new conceptual approach.