Les chordomes de la base du crâne et du rachis cervical haut. À propos d'une série de 100 patients irradiés selon une technique conformationnelle 3D par une association de faisceaux de photons et de protons

Skull base chordomas: clinical outcome in a consecutive series of 45 patients with long-term follow-up and evaluation of clinical and biological prognostic factors

OBJECTIVE

Skull base chordomas (SBCs) are rare dysembryogenetic invasive tumors with a variable tendency for recurrence. According to previous studies, the recurrence rate seems to be affected by both clinical variables and tumor biological features. The authors present the results of treatment of SBCs in a large series of patients and investigate the role of 1p36 chromosomal region loss of heterozygosity (LOH) as a prognostic factor.

METHODS

Between 1990 and 2011, 45 patients were treated for SBCs. The mean follow-up was 76 months (range 1–240 months). An LOH analysis was performed in 27 cases. Survival analysis was performed to determine clinical and biological parameters correlating with clinical outcome.

RESULTS

The 5- and 10-year overall survival rates were 67% and 57%, respectively. Five- and 10-year progression-free survival rates were 58% and 44%, respectively. Multivariate analysis showed that extent of resection, adjuvant radiation therapy, and absence of rhinopharynx invasion were positive independent predictors of overall survival. The latter 2 variables and a younger patient age were positive independent predictors of progression-free survival. Twenty-one patients showed 1p36 LOH. All events of recurrence and death clustered in the group of patients with 1p36 LOH; however, this biological marker was not statistically significant on multivariate analysis.

CONCLUSIONS

Resection is the treatment of choice in primary and recurrent SBC. Patient age, rhinopharynx invasion at diagnosis, extent of tumor removal, and postoperative radiation therapy influence SBC prognosis. Genetic analysis, even while showing interesting results, did not reveal 1p36 LOH as an independent predictor of clinical outcome.

State of the art management in spine oncology: a worldwide perspective on its evolution, current state, and future

STUDY DESIGN

A review of the past and current status of the evolving field of spine oncology.

OBJECTIVE

To provide a framework of reference for developments in the field, particularly the rapidly evolving field of molecular biology, as well as contemporary practice in the management of spine tumors.

METHODS

Literature review of the surgical treatment of spine tumors in the past and present, the emerging radiologic and biologic technologies, as well as the field of targeted therapy in cancer and the economic implications of technological advances.

RESULTS

A vast contemporary literature is currently available that provides a clear rational basis for treatment. Most treatment recommendations are currently based on retrospective data and small Phase II prospective studies. Treatment paradigms continue to evolve without their relative merits being evaluated by randomized controlled trials. The current lack of randomized trials in spine oncology reflect both the rarity of spine tumors and strongly held biases based on retrospective studies and institutional bias.

CONCLUSION

Spine oncology is a rapidly evolving field with contributions in surgery, radiation therapy, and targeted chemotherapy resulting in overall improvement in quality of life and survival in patients with spine tumors. However, the economic consequences of these improvements are substantial and need to be kept in proper perspective.

[An original contention system for hadron therapy]

In hadron therapy centers that have only fixed horizontal beams (i.e. most carbon ions centers and protons centers of first generation), the angulations of the beam remain technically limited, especially for the treatment of children under general anaesthesia with posterior-oblique (40 degrees or so) beams in supine position. We have been developing recently an original positioning system allowing for treatment with posterior-oblique beams, either from right or left directions, by keeping the child in the adequate position.

Cranial base chordoma--long term outcome and review of the literature

BACKGROUND

The purpose of this study is to clarify the latest long-term therapeutic result for cranial base chordomas. We are seeking an improvement of long term therapeutic outcome through a review of cranial base chordomas treated in our institute and of the published literature in the era of multimodality therapy.

MATERIALS AND METHODS

We retrospectively reviewed 13 consecutive patients with cranial base chordoma, including ten males and three females with mean age of 39.5 years (range 5-76 years).

RESULTS

The method of initial treatment included surgery and post-operative conventional local irradiation (IR) in 9 patients, surgery and IR followed by post-operative stereotactic radiosurgery (SRS) in 2 patients, surgery as well as SRS in one patients, and surgery as well as SRS followed by IR in one patient. Subtotal removal (over 95%) was accomplished in eight patients. The mean follow-up period after completion of surgery and initial radiotherapy was 122 months (median 108 months). According to the Kaplan-Meier estimate method, the 5-year survival rate was 82.5%: 11 out of 13 patients survived longer than 5 years and five patients survived longer than 10 years. With a longer follow-up period than the previous reports, our series has provided a 5-year survival rate comparable to that of proton beam therapy. Although our series indicates a favourable outcome, surgical resection followed by IR or SRS failed to control tumour growth in five patients.

CONCLUSIONS

IR and/or SRS provided results comparable with proton beam or heavy particle therapy in our series of cranial base chordomas probably because the radiation field must have covered the target of the tumour volume sufficiently, and reduction of gross tumour volume reduced the target size for radiotherapy. Pursuit of further effective combinations of IR and stereotactic radiotherapy (SRS, proton beam, heavy particle) after tangible resection, especially for residual and recurrent lesions, will be an acceptable framework to achieve a better therapeutic outcome for cranial base chordomas than at present.

Is proton beam therapy cost effective in the treatment of adenocarcinoma of the prostate?

PURPOSE

New treatments are introduced routinely into clinical practice without rigorous economic analysis. The specific aim of this study was to examine the cost effectiveness of proton beam radiation compared with current state-of-the art therapy in the treatment of patients with prostate cancer.

MATERIALS AND METHODS

A Markov model was informed with cost, freedom from biochemical failure (FFBF), and utility data obtained from the literature and from patient interviews to compare the cost effectiveness of 91.8 cobalt gray equivalent (CGE) delivered with proton beam versus 81 CGE delivered with intensity-modulated radiation therapy (IMRT). The length of how many years the model was run, patient's age, probability of FFBF after treatment with proton beam therapy and IMRT, utility of patients treated with salvage hormone therapy, and treatment cost were tested in sensitivity analyses.

RESULTS

Analysis at 15 years resulted in an expected mean cost of proton beam therapy and IMRT of $63,511 and $36,808, and $64,989 and $39,355 for a 70-year-old and 60-year-old man respectively, with quality-adjusted survival of 8.54 and 8.12 and 9.91 and 9.45 quality-adjusted life-years (QALY), respectively. The incremental cost effectiveness ratio was calculated to be $63,578/QALY for a 70-year-old man and $55,726/QALY for a 60-year-old man.

CONCLUSION

Even when based on the unproven assumption that protons will permit a 10-Gy escalation of prostate dose compared with IMRT photons, proton beam therapy is not cost effective for most patients with prostate cancer using the commonly accepted standard of $50,000/QALY. Consideration should be given to limiting the number of proton facilities to allow comprehensive evaluation of this modality.

Radiation tolerance of the rat spinal cord after 6 and 18 fractions of photons and carbon ions: Experimental results and clinical implications

PURPOSE

The tolerance of the rat spinal cord to photon and carbon ion irradiations was investigated to determine the relative biologic effectiveness (RBE) of carbon ions ((12)C) in the plateau region and in a 1 cm spread-out Bragg-peak.

METHODS AND MATERIALS

The cranial part of the cervical and thoracic spinal cord of 336 rats was irradiated with 6 or 18 fractions (Fx) of photons or (12)C-ions, respectively. Animals were followed up for 300 days for the onset of paresis grade II and dose-response curves were calculated.

RESULTS

The D(50)-values (dose at 50% complication probability) were 42.9 +/- 0.5 Gy, 62.2 +/- 0.9 Gy (6 and 18 Fx, (12)C-plateau) and 19.2 +/- 0.2 Gy, 17.6 +/- 0.2 Gy (6 and 18 Fx (12)C-peak), respectively. For photons, the D(50)-values were 57.0 +/- 0.7 Gy for 6 and 88.6 +/- 0.7 Gy for 18 Fx. The corresponding RBE-values were 1.33 +/- 0.02, 1.42 +/- 0.02 (6 and 18 Fx, (12)C-plateau) and 2.97 +/- 0.05, 5.04 +/- 0.08 (6 and 18 Fx (12)C-peak), respectively. Including data of a previously performed experiment for 1 and 2 Fx (1) the parameter alpha/beta of the LQ-model was found to be 2.8 +/- 0.4 Gy, 2.1 +/- 0.4 Gy and 37.0 +/- 5.3 Gy for photon-, (12)C-plateau- and (12)C-peak irradiations, respectively.

CONCLUSIONS

Carbon ion irradiations of the spinal cord are significantly more effective in the peak than in the plateau region. The alpha/beta-values indicate a significant fractionation effect only for the plateau irradiations. In the Bragg-peak, the applied RBE-model correctly describes the main features although it generally underestimates the RBE by 25%. In the plateau region, maximum deviations of up to 20% were found. The acquired data contribute significantly to the validation of the applied RBE-model.